Myocardial ischemia, infarction, heart failure and arrhythmias are the manifestations of coronary artery disease. Reduction of ischemic damage is a major concern of cardiovascular biology research. As per recent studies, the mitochondrial ATP-sensitive potassium channel (mitoKATP) opening is believed to play key role in the physiology of cardioprotection, protection against ischemia-reperfusion injury or apoptosis. However, the structural information of mitoKATP is not precisely known. Elucidating the structural integrity and functioning of the mitoKATP is therefore a major goal of cardiovascular biology research. The known structure and function of the cell ATP-sensitive potassium channel (cellKATP) is functional in interpreting the structural and functional properties of mitoKATP. The primary goal of my research was to characterize the activity of mitoKATP in the isolated mitochondria from the control mouse heart. The mitoKATP activity, if preliminarily characterized in the control strains through the light scattering technique, then the structure of the channel could possibly be established and analyzed by means of the transgenic model and with the help of immunological techniques such as western blotting and immunoflorescence. With this experimental model it was possible to demonstrate that the mitoKATP activity in control mouse heart mitochondria is activated by potassium channel openers (KCOs) such as diazoxide and cromakalim and activators of mitoKATP such as PMA (phorbol12 myristate-13-acetate), and inhibited by KATP inhibitors such as glibenc1amide and 5-hydroxydecanoate (5 HD). It was evident that the KATP activity in mouse heart mitochondria was comparable to that exhibited by the rat heart mitochondria. The various selective and non-selective activators and inhibitors of the channel elicited their activity at a similar concentration used for the rat heart mitochondria. The results were reproducible in five independent experiments for each combination, further reinforcing the significance of existing channel activity in the mouse heart mitochondria.

D.Phil. (Biokinetics) / Please refer to full text to view abstract

Thesis (MScMed)--Stellenbosch University, 2008. / ENGLISH ABSTRACT: It has recently been observed that the application of multiple short cycles of reperfusion and ischaemia, at the onset of reperfusion, elicits cardioprotection against injury due to prior sustained ischaemia. This phenomenon has been termed “postconditioning” (postC) and is of special interest due to its clinical applicability. Although much work has been done to delineate the mechanism of protection, there is still controversy regarding the precise algorithm of postC, the importance of the reperfusion injury salvage kinases (RISK), as well as uncertainty about the possible role of p38 MAPK and the protein phosphatases in postC cardioprotection. The aims of this study were therefore: I. To develop and characterise a cardioprotective postC protocol in the ex vivo rat heart, using both the retrogradely perfused and working heart models. II. To characterise the profiles of PKB/Akt, ERK p42/p44 and p38 MAPK associated with the postC intervention. III. To investigate the possible role of the serine/threonine protein phosphatases type 1 and type 2A (PP1 and PP2A) in the mechanism of postC. Hearts from male Wistar rats were perfused in both the retrograde Langendorff (at a perfusion pressure of 100 cmH2O and diastolic pressure set between 1 and 10 mmHg) and working heart models (preload: 15 cmH20 and afterload: 100 cmH20). Several different postC protocols were tested for their cardioprotective effect, as analysed by infarct size (IFS; determined by triphenyltetrazolium chloride (TTC) staining) and functional recovery. Experimental parameters tested were the number of cycles (3,4 or 6), the duration of the cycles (10, 15, 20 or 30 seconds), the method of application (regional or global) and temperature during the intervention (36.5 or 37 °C). Different sustained ischaemic insults were also utilised: 35 minutes regional (RI) or 20, 25, 30 and 35 minutes global ischaemia (GI). Hearts treated with a cardioprotective postC intervention or standard reperfusion after sustained ischaemia, were freeze-clamped at 10 and 30 minutes reperfusion in both perfusion models. Tissue samples were then analyzed using Western blotting, probing for total and phosphorylated PKB/Akt, ERK p42/p44 and p38 MAPK. The contribution of PKB/Akt and ERK p42/p44 activation to cardioprotection was also investigated by administration of inhibitors (A6730 and PD098059 respectively) in the final 5 minutes of ischaemia and the first 10 minutes of reperfusion, in the presence and absence of the postC intervention. The effect of these inhibitors were analyzed in terms of IFS and kinase profiles. The possible role of the phosphatases in postC was investigated by observing the effect of cantharidin (a PP1 and PP2A inhibitor) treatment directly before sustained ischaemia (PreCanth) or in reperfusion (PostCanth), in the presence and absence of postC, on IFS and kinase profiles. A postC protocol of 6x10 seconds global reperfusion / ischaemia, at 37°C, was found to give the best and most consistent reduction in infarct size in both the Langendorff (IFS in NonPostC: 47.99±3.31% vs postC: 27.81±2.49%; p<0.0001) and working heart (IFS in NonPostC: 35.81±3.67% vs postC: 17.74±2.73%, p<0.001) models. It could however only improve functional recovery in the Langendorff model (after 30 minutes GI: rate pressure product (RPP) recovery: NonPostC = 12.27±2.63% vs postC = 24.61±2.53%, p<0.05; and after 35 minutes GI: left ventricular developed pressure (LVDP) recovery: NonPostC = 28.40±7.02% vs postC = 48.49±3.14%, p<0.05). This protection was associated with increased PKB/Akt (NonPostC: 0.88±0.26 AU (arbitrary unit) vs postC: 1.65±0.06 AU; p<0.05) and ERK p42 (NonPostC: 2.03±0.2 AU vs postC: 3.13±0.19 AU; p<0.05) phosphorylation. Inhibition of PKB/Akt activation with A6730 (2.5 μM) abrogated the infarct sparing effect of postC. Administration of cantharidin, either before of after ischaemia, in the absence of postC, conferred an infarct sparing effect (IFS in PreCanth: 15.42±1.80%, PostCanth: 21.60±2.79%; p<0.05) associated with an increase in the phosphorylation of MAPK p38 (administration before ischaemia: NonCanth: 1.52±0.26 AU vs PreCanth: 2.49±0.17 AU, p<0.05; and administration after ischaemia: NonCanth: 5.64±1.17 AU vs PostCanth: 10.69±1.29 AU, p<0.05) and ERK p42 (when administered in reperfusion; NonCanth: 2.24±0.21 AU vs PostCanth: 3.34±0.37 AU; p<0.05). Cantharidin treatment combined with the postC intervention did not elicit an additive infarct sparing effect (postC: 17.74±2.72%, PreCanth-postC: 13.30±3.46% and PostCanth-postC: 15.39±2.67%). In conclusion: a postC protocol of 6x10 seconds global ischaemia / reperfusion, at 37°C, confers the best infarct sparing effect in both the Langendorff and working rat heart models. This protection is associated with ERK p42 and PKB/Akt phosphorylation, although only PKB/Akt is necessary for cardioprotection. We could not find evidence for PP1 and PP2A involvement in postC, although inhibition of these phosphatases per se does elicit an infarct sparing effect. The latter observation suggests that phosphatase activation during ischaemia / reperfusion is potentially harmful. / AFRIKAANSE OPSOMMING: Dit is onlangs waargeneem dat toediening van meervoudige siklusse herperfusie / iskemie, met die aanvang van herperfusie, die hart teen iskemie / herperfusie beskadiging beskerm. Hierdie verskynsel, bekend as postkondisionering (postC), geniet tans baie aandag vanweë die kliniese toepaslikheid van die ingreep. Ten spyte van intensiewe navorsing om die betrokke meganisme van beskerming vas te stel, is daar steeds kontroversie oor die presiese algoritme van die ingreep, asook die betrokkenheid van die sogenaamde iskemie herperfusie oorlewings kinases (RISK). Daar bestaan ook onsekerheid oor die rol van die stres-kinase, p38 MAPK, asook die proteïen fosfatases in die meganisme van beskerming teen iskemiese besering. Hierdie studie het dus drie doelstellings gehad: I. Ontwikkeling van ‘n postC protokol wat beskerming ontlok in die rothart ex vivo, deur gebruik te maak van beide die retrograad geperfuseerde ballon model, asook die werkhart model. II. Analiese van die profiele van die kinases PKB/Akt, ERK p42/p44 en p38 MAPK tydens herperfusie van postC en kontrole (NonPostC) harte. III. Ondersoek na die moontlike rol van die serien / treonien proteïen fosfatases tipe 1 en tipe 2A (PP1 en PP2A) in die meganisme van postC beskerming. Harte van manlike Wistar rotte is geperfuseer in beide die retrograad geperfuseerde ballon (d.i. die Langendorff) model (teen ‘n konstante perfusie druk van 100 cmH20 en ‘n diastoliese druk gestel tussen 1 en 10 mmHg), asook die werkhart model (teen ‘n voorbelading van 15 cmH20 en ‘n nabelading van 100 cmH20). Verskeie moontlike postC protokolle is getoets vir hul vermoë om kardiobeskerming te ontlok, in terme van funksionele herstel en infarktgrootte (IFS), soos bepaal deur trifenieltetrazolium chloried (TTC) kleuring. Die eksperimentele veranderlikes tydens die postC protokol wat ondersoek is, sluit in: die aantal siklusse (3, 4 of 6), die duur van die siklusse (10, 15, 20 of 30 sekondes), die wyse van postC toediening (streeks of globaal) en laastens die temperatuur tydens die ingreep (36.5 of 37 °C). Daar is ook gebruik gemaak van verskillende periodes iskemie: 35 minute streeks iskemie (RI), asook 20, 25, 30 en 35 minute globale iskemie (GI). Na 10 of 30 minute herperfusie is harte wat blootgestel is aan ‘n kardiobeskermende postC ingreep of gewone standaard herperfusie na iskemie, in beide perfusie modelle, gevriesklamp. Die weefsel proteïen-inhoud is verder geanaliseer deur van die Western blot tegniek gebruik te maak vir bepaling van die totale en fosforileerde vlakke van PKB/Akt, ERK p42/p44 en p38 MAPK. Die funksionele belang van PKB/Akt en ERK p42/p44 is verder ondersoek deur die effek van ‘n geskikte inhibitor (onderskeidelik A6730 en PD098059, toegedien tydens die laaste 5 minute van iskemie en die eerste 10 minute van herperfusie), in die teenwoordigheid en afwesigheid van die postC ingreep, op infarktgrootte en kinase aktiwiteit te monitor. Die moontlike rol van proteïen fosfatases in postC is ondersoek deur die effek van cantharidin (‘n PP1 en PP2A inhibitor) op infarktgrootte en kinase profiele te ondersoek. Cantharidin is óf onmiddelik voor iskemie óf tydens herperfusie toegedien, in die aan – en afwesigheid van die postC ingreep. Daar is bevind dat ‘n postC protokol van 6x10 sekondes globale iskemie / herperfusie, teen 37°C, die mees effektiewe en konstante verlaging in infarktgrootte teweeg gebring het in beide die ballon model (IFS in NonPostC: 47.99±3.31% vs postC: 27.81±2.49%; p<0.0001), asook die werkhart (IFS in NonPostC: 35.81±3.67% vs postC: 17.74±2.73%, p<0.001). Funksionele herstel kon egter slegs ontlok word in die ballon model (na 30 minute GI: tempo druk produk (RPP) herstel: NonPostC = 12.27±2.63% vs postC = 24.61±2.53%, p<0.05; en na 35 minute GI: linker ventrikulêre ontwikkelde druk (LVDP) herstel: NonPostC = 28.40±7.02% vs postC = 48.49±3.14%, p<0.05). Die infarkt-besparende effek van postC was geassosieer met ‘n toename in die fosforilasie van beide PKB/Akt (NonPostC: 0.88±0.26 AU (arbitrêre eenhede) vs postC: 1.65±0.06 AU; p<0.05) en ERK p42 (NonPostC: 2.03±0.2 AU vs postC: 3.13±0.19 AU; p<0.05). Inhibisie van PKB/Akt met A6730 (2.5 μM) het die infarkt-besparende effek van postC opgehef. Inhibisie van PP1 en PP2A opsigself, deur toediening van cantharidin óf voor óf na iskemie (in die afwesigheid van postC), het ‘n infarkt-besparende effek ontlok (IFS in PreCanth: 15.42±1.80%, PostCanth: 21.60±2.79%; p<0.05). Hierdie kardiobeskerming was geassosieer met ‘n toename in die fosforilasie van beide p38 MAPK (met toediening voor iskemie: NonCanth: 1.52±0.26 AU vs PreCanth: 2.49±0.17 AU, p<0.05; en toediening na iskemie: NonCanth: 5.64±1.17 AU vs PostCanth: 10.69±1.29 AU, p<0.05), asook ERK p42, indien cantharidin toegedien is tydens herperfusie (NonCanth: 2.24±0.21 AU vs PostCanth: 3.34±0.37 AU; p<0.05). Kombinasie van cantharidin behandeling met postC toediening kon egter nie ‘n kumulatiewe infarkt-besparende effek uitlok nie (postC: 17.74±2.72%, PreCanth-postC: 13.30±3.46% en PostCanth-postC: 15.39±2.67%). In samevatting: ‘n PostC protokol van 6x10 sekondes globale iskemie / herperfusie, teen 37°C, ontlok die mees effektiewe infarkt-besparende effek in beide die ballon, sowel as die werkhart modelle. Alhoewel hierdie beskerming geassosieer is met ‘n toename in die fosforilasie van beide PKB/Akt en ERK p42/p44 tydens herperfusie, is dit slegs PKB/Akt wat van funksionele belang is in die meganisme van kardiobeskerming. Ons kon geen bewyse vind vir die betrokkenheid van PP1 en PP2A in postC beskerming nie, alhoewel inhibisie van hierdie fosfatases opsigself infarkt-besparend is. Laasgenoemde waarneming toon dat fosfatase aktivering tydens iskemie / herperfusie skadelike gevolge mag hê.

心臟病目前仍然是最普遍的威脅人類生命安全的三大病因之一。同西藥相比, 傳統中醫藥具有多靶點，協同作用及小副作用等特性。在中藥歷史中， 丹參和葛根這兩種草藥經常出現在中藥方劑用於治療心血管相關的疾病，已有幾千年的歷史。 我們實驗室發現了一個丹參葛根湯劑具有保護動脈粥樣硬化病人心臟功能的作用，並且可以使收縮的大鼠大動脈舒張的作用。 本研究主要通過舒張豬冠狀動脈，提高大鼠對抗過氧化和離子擾動能力以及提高血管增生四個方面探討丹參葛根複方水提物 (質量比7:3) (DG配方)對血管的作用以提供其治療心血管疾病的藥理基礎。 / 在本研究的第一部， 我們主要探討了DG配方對缺血再灌注損傷的心臟及其心肌細胞的保護作用。我們發現DG配方明顯抑制了心臟損傷相關的肌酸激酶和乳酸脫氫的釋放。同時DG配方顯著促進了再灌注後冠狀動脈內血流量速度和收縮力度的恢復。這些結果說明DG配方可以保護缺血再灌注心臟並且有效促進其功能恢復。我們還觀察了長期給大鼠用DG配方14天後其心臟在缺血再灌注中的表現。類似於再灌注時給藥的結果，DG配方同樣抑制了損傷酶的釋放並且有效促進了冠狀動脈內血流量速度和收縮力度的恢復。 / 同時，在缺氧再灌注離體細胞模型中，我們發現DG配方明顯抑制了缺氧再灌注損傷帶來的細胞死亡。流式細胞儀分析結果表明，藥物處理組中的凋亡類的細胞明顯比對照組中少主要通過抑制促凋亡的caspase3表達明以及促進抗凋亡的Bcl2表達升高。DG配方減少了心肌細胞內細胞色素c從線粒體中釋放明顯以及抑制了線粒體去極化。這說明DG配方也保護了線粒體的膜的完整性，從而確保線粒體功能進而保證細胞的能量系統穩定。最有意思的是DG配方可以直接抑制缺氧再灌注相關的兩條通路, 它不僅抑制活性氧化物質的釋放, 同時也抑制了再灌注後鈣離子的累積。總之，DG配方以抗氧化和抗離子擾動的方式保護了在缺血缺氧再灌注損傷中心臟和心肌細胞的結構和功能。 / 第二部分的研究是關於DG配方對從豬心臟上分離的左冠狀動脈前室間支 (左前降支) 血管的作用及其內在的機制，我們的結果表明對由U46619引起的冠狀動脈血管收縮DG配方表現了濃度依賴的舒血管作用。而該作用並非依賴于內皮細胞及其釋放的舒張血管因數一氧化氮和前列腺素類似物環素和大部分的鉀離子通道。其中只有內向整合鉀離子通道部分參與了舒血管的過程。肌球蛋白輕鏈的磷酸化明顯被DG配方抑制，但是RhoA 的活性並沒有受其影響。鈣離子引發的血管收縮則被DG配方濃度依賴性的受到抑制。這部分的研究證明瞭DG配方主要通過類似鈣離子通道拮抗劑作用抑制鈣離子進入到血管平滑肌細胞減少肌球蛋白磷酸化達到舒張血管的作用。結果說明DG配方可以作為一種安全的藥物用於治療心血管疾病特別是高血壓和心絞痛。 / 本研究的第三部分是關於DG配方的促血管增生的作用。我們發現DG配方可以明顯促進斑馬魚的腸下動脈的出芽並且促進血管增生相關基因的表達，血管內皮細胞生長因數及其受體的mRNA表達。內皮細胞是血管增生的基礎。所以我們利用人源微血管內皮細胞檢測了DG配方在細胞的增生，遷移，分化和形成血管方面的影響以解釋它在斑馬魚中促進血管增生的作用機理。結果發現，DG配方明顯促進了該種內皮細胞的增殖，遷移和形成管狀結構。 / 綜上所述，DG配方可以通過舒張血管，抗氧化，抗離子紊亂和促進血管增生提供心血管保護功能。DG配方通過螯合活性氧化物質和抑制鈣離子的累積保護了因缺血再灌注引起的心臟損傷，說明DG配方可以作為手術的輔助藥物減少心臟病人在缺血再灌注過程中受到的損傷。它以拮抗L型鈣離子通道方式減少鈣離子進入到血管平滑肌細胞來舒張收縮的冠狀動脈血管。說明DG配方可以用於治療高血壓和心絞痛等心臟病。另外DG配方也可以促進血管增生，可用于心肌梗死病人促進其心臟血管系統重建，本研究對於未來臨床實驗具有重要的參考價值。 / Coronary heart diseases (CHD) are one of the most prevalent causes of premature death all over the world. In contrast to western medicine, traditional Chinese medicine (TCM) has shown the benefit of multi-targeting and synergism to treat CHD. Two kinds of Chinese herbs, Danshen (Radix Salviae Miltiorrhiza) (D) and Gegen (Radix Puerariae Lobatae) (G) always present on the TCM formula for treating heart disease. We found a useful formula of Danshen and Gegen decoction with weight ratio of 7:3 (DG) exerting properties of improving the heart function in patient with atheroslcerosis and providing vasodiation and antioxidant protection on the rat cardiovascular system. The present study was designed to evaluate the effects of DG on the vascular activity by its properties on antioxidant and anti-ion stunning to inhibiting the ischemia and reperfusion injury, vasodilation effect on pig coronary artery and angiogenesis effect on zebrafish model. / In the first part of the study, we explored protective effect of DG on rat hearts and cardiomyocytes after ischemia-reperfusion and hypoxia-reoxygenation injury. Comparing to control group, the release of creatine kinase (CK) and lactate dehydrogenase (LDH) significantly decreased in the DG treated groups in a dose-dependent manner. The recovery percentage of coronary flow and contractile force in the DG was higher than that in the control group. These results suggested that DG dose-dependently improved the heart function after ischemia and reperfusion injury in a dose-dependent manner. We also examined chronic effect of DG (14 days pretreatment) on rat heart with ischemia and reperfusion injury. DG induced rat heart with high potential to deal with I/R injury, less damaged enzymes release and high recovery percentage of heart function recovery. / In the cell hypoxia and reoxygenation model, DG significantly inhibited the cell death after H/R treatment with bcl2 expression increase and caspase3 expression decrease. DG also reversed the H/R-induced mitochondrial depolarization and inhibited cytochrome c diffusing out of mitochondria, which confirmed DG anti-apoptosis activity. DG also was found to significantly decrease the intracellular calcium accumulation and reactive oxygen species release within H9c2. / In the second part of present study, results revealed that DG elicited a concentration-dependent relaxation of U46619-preconstricted porcine coronary artery. DG-induced relaxation responses were not altered by the presence of endothelium-related dilator inhibitors, most potassium channel blockers, GMP and AMP pathway inhibitors and endothelium removal. Ba²⁺ (an inward rectifier K⁺ channel blocker) slightly attenuated DG-induced relaxation. The protein expression of phosphorylated myosin light chain (MLC) was inhibited by DG in a concentration-dependent manner whereas the activity of RhoA was not modified. Ca²⁺-induced contraction of coronary artery was inhibited by DG in a concentration-dependent fashion. DG acted as an antagonist of calcium channel inducing the porcine artery dilation. / The third part of the present study is about the pro-angiogenic effect of DG. We found that DG dose-dependently induced zebrafish sub-intestinal vessel sprouting and increased the mRNA expression of vascular endothelial growth factor (VEGF) and its receptors. To explore the underlying mechanism, we also examined the proangiogenic effect of DG on the angiogenesis of endothelial cells. The results showed that DG induced the HMEC-1 proliferation, migration and forming tube. / In conclusion, we found that DG could provide cardiac and cardiovascular protection by its multiple targets. It prevented heart injuries after ischemia or hypoxia and reperfusion through scavenging ROS and inhibiting calcium accumulation. Moreover, it mainly acts as an antagonist of L-type calcium channel to relax the contracted LAD vessel. It also exerted property of inducing angiogenesis in vivo and in vitro. Therefore, DG would be useful for treating coronary artery disease depending on its multiple targets. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Hu, Fan. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 170-215). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / Chapter 1 --- Intorduction --- p.1 / Chapter 1.1 --- Cardiovascular system and coronary artery diseases --- p.1 / Chapter 1.1.1 --- The cardiovascular system --- p.1 / Chapter 1.1.2 --- Contraction and relaxation of the vascular myocyte in arteries --- p.4 / Chapter 1.1.2.1 --- Ultrastructure of the vascular myocyte --- p.4 / Chapter 1.1.2.2 --- Contraction mechanisms of vascular myocyte --- p.5 / Chapter 1.1.2.3 --- Relaxation mechanisms of vascular myocyte --- p.7 / Chapter 1.1.3 --- Chronic coronary heart disease --- p.9 / Chapter 1.2 --- The way to treat chronic CAD --- p.11 / Chapter 1.2.1 --- Angiogenesis --- p.11 / Chapter 1.2.2 --- Clinical surgery for treating CAD --- p.13 / Chapter 1.2.2.1 --- Three common surgeries for treating CAD --- p.13 / Chapter 1.2.2.2 --- Ischemia and reperfusion (I/R) injury in surgeries --- p.15 / Chapter 1.2.3 --- Drugs for treating CAD --- p.19 / Chapter 1.2.3.1 --- Western medicine therapy in CAD --- p.19 / Chapter 1.2.3.2 --- Traditional Chinese Medicine treatment in CAD --- p.20 / Chapter 1.3 --- Aims of studies --- p.28 / Chapter 2 --- Materials and Methods --- p.29 / Chapter 2.1 --- Solutions and Materials --- p.29 / Chapter 2.1.1 --- Solutions --- p.29 / Chapter 2.1.2 --- Chemicals and enzymes --- p.36 / Chapter 2.2 --- Methods --- p.38 / Chapter 2.2.1 --- Herbal preparation --- p.38 / Chapter 2.2.2 --- Identification and quantification of chemical markers in Danshen and Gegen decoction (DG) --- p.38 / Chapter 2.2.3 --- Assay development for the determination of the DG marker compounds in rat plasma --- p.40 / Chapter 2.2.4 --- Isolation of pig left anterior descending coronary artery --- p.44 / Chapter 2.2.5 --- Isometric tension measurement --- p.45 / Chapter 2.2.6 --- Langendorff related experiment --- p.50 / Chapter 2.2.7 --- Cell culture of H9c2 cells --- p.54 / Chapter 2.2.8 --- Cell viability assay (MTT assay) --- p.56 / Chapter 2.2.9 --- Cell proliferation measurement --- p.57 / Chapter 2.2.10 --- Hypoxia and reperfusion cell model (H9c2) --- p.58 / Chapter 2.2.11 --- Determination of cell apoptosis with Annexin VFITC and PI double staining --- p.59 / Chapter 2.2.12 --- Measurement of mitochondria depolarization --- p.61 / Chapter 2.2.13 --- Measurement of ROS release --- p.63 / Chapter 2.2.14 --- Measurement of calcium localization in H9c2 cells by fluo4 dye and confocal microscopy --- p.64 / Chapter 2.2.15 --- Extraction of proteins from tissue, cell and subcellular fractions --- p.65 / Chapter 2.2.16 --- Western blot assay --- p.67 / Chapter 2.2.17 --- Human microvascular endothelial cells (HMEC1) cell culture --- p.68 / Chapter 2.2.18 --- Cell cycle analysis by PI staining --- p.69 / Chapter 2.2.19 --- Scratch assay for HMEC1cells migration --- p.70 / Chapter 2.2.20 --- Tube formation assay --- p.71 / Chapter 2.2.21 --- Vessel sprouting of Zebrafish --- p.72 / Chapter 2.2.22 --- Real time PCR --- p.74 / Chapter 2.2.23 --- Statistical analysis --- p.76 / Chapter 3 --- Chapter 3 Cardiac protection of Danshen and Gegen decoction in hypoxia/ischemia and reperfusion induced injury --- p.77 / Chapter 3.1 --- Introduction --- p.77 / Chapter 3.2 --- Results --- p.81 / Chapter 3.2.1 --- Cytotoxicity of DG --- p.81 / Chapter 3.2.2 --- The morphology alteration of H9c2 after H/R treatment --- p.83 / Chapter 3.2.3 --- Effect on H H9c2 cell survival after H/R treatment --- p.84 / Chapter 3.2.4 --- Effect on membrane skeleton of H9c2 cells with H/R injury --- p.86 / Chapter 3.2.5 --- Effect on the apoptosis in H9c2 cells induced by H/R injury --- p.88 / Chapter 3.2.6 --- Effect on cytochrome c release from mitochondria of damaged H9c2 cells --- p.92 / Chapter 3.2.7 --- Effect on mitochondria depolarization of H9c2 after H/R treatment --- p.94 / Chapter 3.2.8 --- Effect on reactive oxidant species (ROS) release --- p.96 / Chapter 3.2.9 --- Effect on calcium accumulation within H9c2 in the reperfusion phase --- p.98 / Chapter 3.2.10 --- Effect on heart functions of rat hearts with I/R injury (acute effect) --- p.101 / Chapter 3.2.11 --- Effect on heart function in rats with I/R injury (chronic effect) --- p.107 / Chapter 3.3 --- Discussion --- p.113 / Chapter 4 --- Chapter 4 Vasodilation effects of Danshen and Gegen decoction in porcine coronary artery and its underlying mechanism --- p.118 / Chapter 4.1 --- Introduction --- p.118 / Chapter 4.2 --- Results --- p.121 / Chapter 4.2.1 --- Investigations of endothelium dependent and independent mechanisms --- p.121 / Chapter 4.2.2 --- Effects on cAMP and cGMP pathway --- p.121 / Chapter 4.2.3 --- Effects on potassium channel opening --- p.121 / Chapter 4.2.4 --- Effects on calcium induced contraction and calcium sensitization --- p.122 / Chapter 4.2.5 --- Effects on MLC phosphorylations --- p.123 / Chapter 4.3 --- Discussion --- p.132 / Chapter 5 --- Chapter 5 In vitro and in vivo angiogenic effects of DG --- p.138 / Chapter 5.1 --- Introduction --- p.138 / Chapter 5.2 --- Results --- p.140 / Chapter 5.2.1 --- Effect on subintestinal vessels sprouting in the zebrafish embryo --- p.140 / Chapter 5.2.2 --- Effect on the transcription and expression of VEGFA and VEGF receptors -- Flt1 and KDR/Flk2 --- p.143 / Chapter 5.2.3 --- Effect on HMEC1 proliferation --- p.145 / Chapter 5.2.4 --- Effect on cell cycle of HMEC1 --- p.148 / Chapter 5.2.5 --- Effect on cell migration of HMEC1 --- p.151 / Chapter 5.2.6 --- Effect on tube formation of HMEC1 --- p.154 / Chapter 5.3 --- Discussion --- p.157 / Chapter 6 --- Chapter 6 Conclusions and future work --- p.160 / Chapter 6.1 --- Cardiac protection of DG in the I/R and H/R injury --- p.160 / Chapter 6.2 --- Vasodilation effect of DG on the porcine coronary artery --- p.165 / Chapter 6.3 --- Angiogenic effect of DG in vivo and in vitro --- p.167 / Chapter 6.4 --- Overall conclusion of the study --- p.169 / Chapter 7 --- References --- p.170

Yam Wing Sze. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 154-160). / Abstracts in English and Chinese. / Abstract English --- p.i / Chinese --- p.iii / Acknowledgments --- p.v / Table of contents --- p.vii / List of Tables --- p.x / List of Figures --- p.xi / List of Abbreviations --- p.xvi / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Chinese Medicine and Western Medication --- p.1 / Chapter 1.2 --- Chinese Medicine and Compound Formula --- p.2 / Chapter 1.3 --- Cardiovascular disease (CVD) and atherosclerosis --- p.6 / Chapter 1.4 --- General Research Objectives --- p.19 / Chapter Chapter 2 --- Establishment of compound formulation and Extract Preparation --- p.21 / Chapter 2.1 --- Formulation searched from Chinese Pharmacopoeia --- p.21 / Chapter 2.2 --- Aqueous extract preparation --- p.25 / Chapter 2.2.1 --- Materials and Methods --- p.25 / Chapter 2.2.2 --- Discussion --- p.27 / Chapter Chapter 3 --- Vasodilation study --- p.28 / Chapter 3.1 --- Vascular Smooth Muscle Contraction and Relaxation --- p.28 / Chapter 3.2 --- Endothelium and Vasodilation --- p.30 / Chapter 3.3 --- Vasodilation in organ bath --- p.32 / Chapter 3.3.1 --- Materials and Methods --- p.32 / Chapter 3.3.2 --- Results --- p.35 / Chapter 3.3.3 --- Discussion --- p.40 / Chapter 3.4 --- Endothelium dependent vasodilation --- p.40 / Chapter 3.4.1 --- Materials and Methods --- p.43 / Chapter 3.4.2 --- Results --- p.45 / Chapter 3.4.3 --- Discussion --- p.54 / Chapter 3.5 --- Adrenoceptor and vasodilation --- p.55 / Chapter 3.5.1 --- Materials and Methods --- p.57 / Chapter 3.5.2 --- Results --- p.58 / Chapter 3.5.3 --- Discussion --- p.62 / Chapter 3.6 --- Potassium Channels and Vasodilation --- p.63 / Chapter 3.6.1 --- Materials and Methods --- p.65 / Chapter 3.6.2 --- Results --- p.67 / Chapter 3.6.3 --- Discussion and Summary --- p.77 / Chapter 3.7 --- Potential active components from Fenge and Danshen --- p.82 / Chapter 3.7.1 --- Materials and Methods --- p.82 / Chapter 3.7.2 --- Results --- p.83 / Chapter 3.7.3 --- Discussion --- p.87 / Chapter Chapter 4 --- Comparison of Fenge and Yege --- p.88 / Chapter 4.1 --- Vasodilative effects of Fenge and Yege --- p.89 / Chapter 4.1.1 --- Materials and Methods --- p.89 / Chapter 4.1.2 --- Results --- p.89 / Chapter 4.1.3 --- Discussion --- p.101 / Chapter 4.2 --- The comparison of antioxidative effect between Yege and Fenge --- p.104 / Chapter 4.2.1 --- Red blood cell hemolysis model --- p.106 / Chapter 4.2.1.1 --- Materials and Methods --- p.106 / Chapter 4.2.1.2 --- Results --- p.108 / Chapter 4.2.1.3 --- Discussion --- p.110 / Chapter 4.2.2 --- Ischemia-reperfusion on Langendroff --- p.112 / Chapter 4.2.2.1 --- Materials and Methods --- p.114 / Chapter 4.2.2.2 --- Results --- p.117 / Chapter 4.2.2.3 --- Discussion --- p.125 / Chapter Chapter 5 --- Comparison of Chemical Profiles of Fenge and Yege --- p.127 / Chapter 5.1 --- The application of HPLC --- p.127 / Chapter 5.2 --- HPLC standardization --- p.129 / Chapter 5.2.1 --- Materials and Methods --- p.132 / Chapter 5.2.2 --- Results --- p.133 / Chapter 5.2.3 --- Discussion --- p.144 / Chapter Chapter 6 --- "Summaries, Discussion and prospects" --- p.146 / Chapter 6.1 --- Summaries and Discussion --- p.146 / Chapter 6.2 --- Prospects --- p.148 / Chapter 6.2.1 --- "Cardiovascular tonic effect of pure compounds, extracts with difference solvents and their vasodilative mechanism." --- p.148 / Chapter 6.2.2 --- Macrophage Foam Cell and Atherosclerosis --- p.149 / Chapter 6.2.3 --- The D:F (7:3) and D:Y (7:3) compound formulae capsule with GMP --- p.152 / References --- p.154

Thesis (D. Tech.) -- Central University of Technology, Free State, 2009

Dissertation / The aim of this study was to determine the knowledge of persons with hypertension in a selected geographical area regarding cardiovascular risk factors in order to make recommendations for patient education. A quantitative, non-experimental, descriptive study was done in the form of a survey using a questionnaire as measuring instrument. The population was hypertensive patients from selected private medical practices in the western part of KwaZulu-Natal and the bordering eastern part of the Free State. Convenience sampling was used and 46 respondents participated in the study. Only 16 (35%) of the respondents achieved a percentage on or above the competency indicator of 50%. Respondents performed worst in questions where definitions, for example hypertension, were assessed. Recommendations for a patient education document, nursing practice and further research were made. / Health Studies / M.A. (Health Studies)

Thesis (PhD)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Ischaemic heart disease is a major contributor to global morbidity and mortality rates. Manoeuvres such as ischaemic preconditioning confer cardioprotection against ischaemia/reperfusion (I/R) injury by activating several intracellular signalling pathways. These pathways have been defined solely in terms of the kinases involved, despite the realization in recent years that protein phosphatase activity also contributes significantly to the attributes of the propagated signal. Protein phosphatase 2A (PP2A) is a heteromultimeric enzyme involved in an array of phosphatase reactions. We hypothesized that PP2A is an important participant in the myocardial response to I/R by regulating intracellular signalling. This project aimed to (i) characterize PP2A during myocardial I/R; (ii) determine the importance of its contribution to the cellular response to I/R; and (iii) investigate its role in the signalling pathways mediated by PKB/Akt, GSK-3β, ERK p42/p44 and p38 MAPK. Two models were used to characterize PP2A during I/R: (i) H9c2 cells exposed to simulated ischaemia (SI) buffer in conjunction with hypoxia (0.5% O2) for a maximum of 2 hours, followed by reoxygenation in standard growth medium for up to 30 minutes; and (ii) isolated working rat hearts exposed to a maximum of 20 minutes global ischaemia and 10 minutes reperfusion. In both models samples were collected at several time points during I/R for Western blotting analysis. PP2A-C (the catalytic subunit) accumulated in the nucleus during early ischaemia, but later redistributed to the cytosol. At the end of ischaemia there was an elevation of PP2A-C relative to PP2A-A in the unfractionated whole cell preparation concomitant with an increase in the inhibitory phosphorylation of PP2A-C. The impact of PP2A activity was evaluated by either inhibiting PP2A using okadaic acid (OA, 10 nM) or activating it by administering FTY720 (1 μM) in an isolated working rat heart model exposed to either 35 minutes of regional ischaemia (RI) with infarct size (IFS) as primary end-point, or 20 minutes global ischaemia (GI) with functional recovery as end-point. The results showed that the pre-ischaemic administration of OA or FTY720 reduced or exacerbated IFS respectively, indicating that PP2A activation during I/R favours cell death. OA and FTY720 were also employed to assess the contribution of PP2A to intracellular signalling in an isolated working rat heart exposed to I/R. Samples were collected at several timepoints and analyzed using Western Blotting. Pre-ischaemic administration of OA enhanced the phosphorylation of PKB/Akt, ERK p42/p44 and GSK-3β at the onset of reperfusion, while FTY720 given before ischaemia reduced the phosphorylation of GSK-3β, p38 MAPK and PKB/Akt at the end of ischaemia and onset of reperfusion. In summary, PP2A is part of an early nuclear-based response to ischaemia, while long-term ischaemia induces an increase in PP2A-C. A portion of this PP2A-C is stored in an inactive form, while an active portion acts as a regulator of the pro-survival signalling components PKB/Akt, GSK- 3β and ERK p42/p44 at the end of ischaemia and the onset of reperfusion. PP2A is therefore an important component of the myocardial response to I/R by regulating pro-survival signalling. / AFRIKAANSE OPSOMMING: Iskemiese hartsiekte is een van die belangrikste komponente wat bydra tot globale morbiditeit en mortaliteit. Ingrepe soos iskemiese prekondisionering aktiveer veelvoudige intrasellulêre seintransduksiepaaie om kardiobeskerming teen iskemie/herperfusie (I/H)-besering te ontlok. Die kinases betrokke in hierdie seintransduksiepaaie is reeds deeglik nagevors, terwyl die potensiële belang van die proteïenfosfatases in seintransduksie tot onlangs misken is. Ons hipotese was dat Proteïenfosfatase 2A (PP2A), wat in ‘n wye verskeidenheid fosfatase reaksies betrokke is, ‘n belangrike rolspeler in die miokardiale reaksie op I/H-besering is, deur deelname aan die regulering van intrasellulêre seintransduksie. Hierdie projek het ten doel gehad om (i) PP2A te karakteriseer tydens miokardiale I/H; (ii) die belang van PP2A in die sellulêre reaksie op I/H-besering te bepaal; en (iii) PP2A se rol in die seintransduksiepaaie, gemedieer deur PKB/Akt, GSK-3β, ERK p42/p44 en p38 MAPK, te evalueer. Twee modelle is aangewend om PP2A tydens I/H te karakteriseer: (i) H9c2-selle blootgestel aan ‘n simuleerde iskemiebuffer tesame met hipoksie (0.5% O2) vir ‘n maksimum van 2 uur gevolg deur heroksiginasie in standaardgroeimedium vir verskillende tydsperiodes tot ‘n maksimum van 30 minute; en (ii) geïsoleerde, werkende rotharte blootgestel aan ‘n maksimum van 20 minute globale iskemie en 10 minute herperfusie. In beide modelle is monsters op verskillende tye versamel vir Western-kladanalise. Tydens vroeë iskemie het PP2A-C in die kern toegeneem, waarna dit met verloop van tyd na die sitosol herversprei het. Teen die einde van iskemie was daar ‘n toename in die vlakke van PP2A-C relatief tot PP2A-A in ongefraksioneerde weefselhomogenate, tesame met ‘n toename in die inhibitoriese fosforilering van PP2A-C. Die belang van PP2A-aktiwiteit is ondersoek deur die effek te bepaal van die inhibisie of aktivering daarvan op infarktgrootte (IFS) en funksionele herstel in ‘n geïsoleerde werkende rothartmodel, blootgestel aan onderskeidelik 35 minute streeksiskemie (RI) of 20 minute globale iskemie. Preiskemiese toediening van die PP2A-inhibitor okadaïensuur (OA, 10 nM), of aktiveerder FTY720 (1 μm) het infarktgrootte respektiewelik beperk of vergroot. PP2A-aktivering tydens I/H is dus nadelig. OA en FTY720 is ook aangewend om die bydrae van PP2A tot I/H-verwante, intrasellulêre seintransduksie in die geïsoleerde, werkende rothart te bepaal. Monsters is op verskeie tydintervalle versamel en ontleed deur gebruik te maak van die Western-kladtegniek. Preiskemiese toediening van OA het die fosforilering van PKB/Akt, ERK p42/p44 en GSK-3β by die aanvang van herperfusie bevoordeel, terwyl pre-iskemiese toediening van FTY720, die fosforilering van GSK-3β, p38 MAPK en PKB/Akt aan die einde van iskemie en die begin van herperfusie verminder het. Ter opsomming: PP2A is deel van ‘n vroeë gelokaliseerde kerngebaseerde reaksie op iskemie, terwyl langdurige iskemie ‘n toename in PP2A-C relatief tot PP2A-A induseer. ‘n Deel van hierdie PP2A-C is onaktief, terwyl die res funksioneer in die regulering van die seintransduksiekomponente PKB/Akt, GSK-3β en ERK p42/p44 wat oorlewing fasiliteer met die aanvang van herperfusie. PP2A is dus ‘n belangrike komponent in die miokardiale reaksie op I/H deurdat dit tot die beheer van seintransduksiepaaie bydra.

Dissertation (PhD)--University of Stellenbosch, 2005. / ENGLISH ABSTRACT: Activation of the NO-cGMP pathway is associated with myocardial protection against ischaemia/reperfusion injury. However, high-cholesterol diets alter function of this pathway and these alterations have been implicated in both ischaemic/reperfusion injury and the development of ischaemic heart disease. Little is known about the effects of supplements such as Red Palm Oil (RPO) on the myocardial NO-cGMP-signalling pathway. RPO consists of saturated, mono-unsaturated and poly-unsaturated fatty acids and is rich in antioxidants such as β-carotene and Vitamin E (tocopherols and tocotrienols). The aims of this study were: 1) to determine whether dietary RPO-supplemention protects against ischaemia/reperfusion injury in rats fed a standard rat chow (control) and cholesterol-enriched diets and 2) if so, to investigate possible mechanisms for this protection. Male Long-Evans rats were fed a standard rat chow or a standard rat chow plus cholesterol and/or RPO-supplementation for 6 weeks. Myocardial functional recovery was measured and hearts were freeze-clamped for determination of myocardial phospholipid, cAMP/cGMP concentrations, total myocardial nitric oxide concentrations, lipid hydroperoxide production and superoxide dismutase- and nitric oxide synthase activity in isolated rat hearts subjected to 25 minutes of normothermic total global ischaemia. In addition, the degree of phosphorylation of extracellular signal-regulated kinase (ERK), p38, c-Jun N-terminal protein kinase (JNK) and protein kinase B (PKB/Akt) was investigated. Furthermore, the effect of RPO-supplementation on caspase-3 activation and poly (ADP-ribose) polymerase (PARP)-cleavage in hearts subjected to ischaemia and reperfusion was also investigated. Our data show that dietary RPO-supplementation protects the hearts of rats on a standard rat chow (control) and hypercholesterolaemic diet against ischaemia/reperfusion injury as reflected by improved aortic output recovery. Increased intracellular cardiomyocyte NO concentrations as observed in control hearts supplemented with RPO after 120 minutes hypoxia may contribute to the elevated cGMP concentration and may confer some of the cardioprotection to the ischaemic/reperfused heart. Although improved functional recovery with RPO-supplementation of a high-cholesterol diet was also associated with an increase in intracellular cardiomyocyte NO production after hypoxia compared to the non-hypoxic conditions, it could not be linked to increased NO-cGMP signalling. These data are in agreement with other studies, which showed that high-cholesterol diet impairs NO-cGMP signalling and confirms our hypothesis that elevated cGMP concentrations may not be the only mechanism of protection. We have also shown that RPOsupplementation caused increased phosphorylation of p38 and PKB, reduced phosphorylation of JNK and attenuation of PARP cleavage, which may contribute to the protection of the cell against apoptosis. Based on our results we propose that the myocardial protection offered by RPO-supplementation of rats on a normal and hypercholesterolaemic diet may be associated with either its antioxidant characteristics and/or changes in the fatty acid composition of the myocardium during ischaemia/reperfusion. Furthermore, we demonstrated for the first time that RPO-supplementation protects the isolated perfused working rat heart during reperfusion from ischaemia/reperfusion-induced injury through a MAPK-dependent pathway. / AFRIKAANSE OPSOMMING: Aktivering van die NO-cGMP sein transduksie pad word geassosieer met miokardiale beskerming teen isgemie/herperfusie skade. Hoë cholesterol diëte verander egter die funksie van die pad en hierdie veranderings speel ‘n rol in beide isgemie/herperfusie besering en die ontwikkeling van isgemiese hartsiekte. Daar is egter min inligting beskikbaar oor die uitwerking van aanvullings soos rooi palm olie (RPO) op die miokardiale NO-cGMP sein transduksie pad. RPO bevat versadigde, mono-onversadigde en poli-onversadigde vetsure en is ryk aan anti-oksidante nl. β-karotene en vitamien E (tokoferole en tokotriënole). Die doelwitte van hierdie studie was: 1) om vas te stel of ‘n RPO-aanvulling beskerming bied teen isgemie/herperfusie besering in rotte wat gevoed is met ‘n standaard rotmengsel (kontrole) en cholesterol-verrykte dieet en 2) indien wel, om moontlike meganismes van beskerming te ondersoek. Long-Evans manlike rotte is vir 6 weke gevoer met ‘n standaard rotmengsel of ‘n standaard rotmengsel plus cholesterol en/of RPO-aanvulling. Miokardiale funksionele herstel is gemeet en harte is gevriesklamp vir die bepaling van miokardiale fosfolipied, cAMP/cGMP, totale stikstofoksied, lipied hidroperoksied, superoksied dismutase en stikstofoksied sintase in geïsoleerde rotharte wat vir 25 minute onderwerp was aan normotermiese totale globale isgemie. Hiermee saam is die graad van fosforilering van ekstrasellulêre sein gereguleerde kinase (ERK), p38 mitogeen-geaktiveerde proteïen kinase (p38 MAPK), c-Jun-N-terminale proteïenkinase (JNK) en proteïen kinase B (PKB/Akt) ondersoek, asook kaspase-3 aktivering en poli (ADP-ribose) polimerase (PARP) kliewing in harte blootgestel aan isgemie en herperfusie. Ons resultate toon dat RPO-aanvulling van rotte op ‘n normale en hipercholesterolemiese dieet die hart beskerm soos getoon deur verbeterde herstel van aortiese uitset. Verhoogde intrasellulêre miokardiale NO vlakke in kontrole harte met ‘n RPO-aanvulling wat blootgestel was aan 120 minute hipoksie, mag bygedra het tot die verhoogde cGMP vlakke en beskerming van die hart tydens isgemie en herperfusie. Alhoewel verbeterde funksionele herstel met RPO-aanvulling van ‘n hoë cholesterol dieet ook geassosieer is met ‘n toename in intrasellulêre miokardiale NO produksie ná hipoksiese toestande, kon dit nie verbind word met verhoogde aktivering van die NOcGMP sein transduksie pad nie. Hierdie resultate stem ooreen met ander studies wat aangetoon het dat hoë-cholesterol diëte die NO-cGMP seinpad onderdruk. Hierdie bevinding bevestig ons hipotese dat verhoogde cGMP vlakke moontlik nie die enigste beskermingsmeganisme is nie. Ons resultate het ook gewys dat RPO-aanvulling fosforilering van p38 en PKB/Akt verhoog, fosforilering van JNK verminder en PARP kliewing onderdruk. Dit dui op beskerming van die sel teen apoptose. Ons resultate dui aan dat die miokardiale beskerming wat RPO-dieet aanvulling bied moontlik geassosieer kan word met sy anti-oksidant eienskap en/of veranderinge in die vetsuur samestelling van die miokardium tydens isgemie/herperfusie. Ons het ook vir die eerste keer bewys dat RPO-aanvulling die geïsoleerde geperfuseerde werkende rothart gedurende herperfusie beskerm teen isgemie/herperfusie besering deur die aktivering en/of deaktivering van die MAPK afhanklike pad.

Dissertation / The aim of this study was to determine the knowledge of persons with hypertension in a selected geographical area regarding cardiovascular risk factors in order to make recommendations for patient education. A quantitative, non-experimental, descriptive study was done in the form of a survey using a questionnaire as measuring instrument. The population was hypertensive patients from selected private medical practices in the western part of KwaZulu-Natal and the bordering eastern part of the Free State. Convenience sampling was used and 46 respondents participated in the study. Only 16 (35%) of the respondents achieved a percentage on or above the competency indicator of 50%. Respondents performed worst in questions where definitions, for example hypertension, were assessed. Recommendations for a patient education document, nursing practice and further research were made. / Health Studies / M.A. (Health Studies)