Wong Chi Ming. / "August 2004." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (p. 182-215). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

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Agradecemos a compreensão. on 2017-06-21T17:51:49Z (GMT) / Submitted by CAMILA TAMI STRINGHETTA GARCIA null (camilatami@foa.unesp.br) on 2017-06-21T18:26:14Z No. of bitstreams: 1 Tese repositório.pdf: 1864307 bytes, checksum: 332fcd04d3149c9d08b518d67f80556d (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-06-21T18:38:07Z (GMT) No. of bitstreams: 1 stringhettagarcia_ct_dr_araca.pdf: 1864307 bytes, checksum: 332fcd04d3149c9d08b518d67f80556d (MD5) / Made available in DSpace on 2017-06-21T18:38:07Z (GMT). No. of bitstreams: 1 stringhettagarcia_ct_dr_araca.pdf: 1864307 bytes, checksum: 332fcd04d3149c9d08b518d67f80556d (MD5) Previous issue date: 2017-05-04 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A ocorrência de doenças crônicas e degenerativas é significativamente maior nos organismos durante o envelhecimento, dentre elas, a osteoporose, que resulta em aumento no número de fraturas. As fraturas são as consequências mais dramáticas da osteoporose, sendo que do colo do fêmur é a mais severa, com maior incidência de morbidades e mortalidade. A menor concentração plasmática de estrogênio nas mulheres menopausadas, exerce ação primordial no desenvolvimento desta doença. Desta maneira, o objetivo deste estudo foi estudar a prevenção da osteoporose em decorrência do envelhecimento reprodutivo feminino, especificamente no período de periestropausa, utilizando treinamento de força (TF), raloxifeno (Ral) ou combinação de TF e Ral. Durante 120 dias, ratas Wistar no período do envelhecimento (18 a 21 meses) realizaram TF em escada três vezes por semana, receberam Ral (1mg/Kg/dia) por gavagem, ou realizaram TF associado ao tratamento com Ral. Microarquitetura óssea cortical e trabecular, densidade mineral óssea areal (DMOa), força óssea, imunoistoquímica (OCN, TRAP e SOST) e superfície de osteoclastos do colo do fêmur foram avaliadas, além de PCR (Runx2, Sp7, Alp, Bsp, Ocn, Rank, Rankl, Opg, Trap e Ctsk) e Western Blot (p-ERα e TRAP) do tecido ósseo de todo o fêmur. Os resultados demonstram que os tratamentos modularam o ciclo de remodelamento ósseo de maneiras diferentes: TF estimulou RNAm de marcadores osteoblásticos e osteoclásticos, enquanto Ral diminuiu marcadores osteoclásticos e TF associado a Ral aumentou marcadores osteoblásticos e diminuiu osteoclásticos. Ambos tratamentos resultaram em melhora da microarquitetura trabecular do colo do fêmur de ratas na periestropausa, todavia, apenas o TF foi capaz de melhorar além da microarquitetura trabecular, a cortical e força óssea. Desta maneira, sugerimos que a realização de TF, utilização de Ral ou a associação de TF e Ral durante a periestropausa são intervenções válidas na prevenção de osteoporose em decorrência do envelhecimento reprodutivo feminino, porém os efeitos do TF parecem ser superiores. Levando em consideração que a carga mecânica gerada pelo TF age também em tecidos não esqueléticos, concluímos que TF pode ser intervenção sistêmica para osteoporose. Esses resultados adicionam novas informações à literatura sobre terapêuticas preventivas para osteoporose e fornecem informações relevantes para estudos pré-clínicos. / The association of aging with osteoporosis results in an increased number of fractures. In these fractures, the femoral neck is involved in 75% of affected women and is one of the most dramatic possible consequences. The aim of this study was to prevent female osteoporosis using strength training (ST), raloxifene (Ral) or a combination of ST plus Ral during the natural female aging process, specifically in the periestropause period. For 120 total days, aging female Wistar rats at 18-21 months of age performed ST on three times per week, and Ral was administered daily by gavage (1mg/kg/day). Bone microarchitecture, areal bone mineral density (aBMD), bone strength of the femoral neck, immunohistochemistry, western blotting (p-ERα and TRAP) and RT-PCR were assessed. We found that the treatments modulate the bone remodeling cycle in different ways. Both ST and Ral treatment resulted in improved bone microarchitecture in the femoral neck of rats in late periestropause. However, only ST improved cortical microarchitecture and bone strength in the femoral neck. In addition, ST stimulated mRNA levels of osteoclastic and osteoblastic markers, while Ral decreased mRNA levels of osteoclastic markers. The combined ST plus Ral therapy increased osteoblastic markers and decreased osteoclast markers. In this way, we suggest that SF, the use of Ral or the association of ST and Ral during periestropause are valid interventions in the prevention of osteoporosis due to female reproductive aging, but the effects of ST seem to be superior, taking into account that the mechanical load generated by ST also acts on nonskeletal tissues, we conclude that ST can be a systemic intervention for osteoporosis. These results add new information to the literature on preventive therapies for osteoporosis and provide relevant information for preclinical studies.

<p>Raloksifen je predstavnik selektivnih modulatora estrogenih receptora koji se koristi u terapiji osteoporoze i invazivnog oblika raka dojke u postmenopauzi. Raloksifen se relativno dobro resorbuje iz gastrointestinalnog trakta, ali pri prvom prolasku kroz jetru podleže biotransformaciji u značajnom procentu, &scaron;to je uzrok njegove niske biolo&scaron;ke raspoloživosti. Bioraspoloživost kod ljudi iznosi 2%, a kod Wistar pacova 39%. Različite supstance se koriste da bi se pobolj&scaron;ala bioraspoloživost lekova. Žučne kiseline, kao &scaron;to je deoksiholna kiselina, omogućavaju bolji prolazak kroz biolo&scaron;ke membrane drugim supstancama, te mogu povećati bioraspoloživost lekova. Apigenin je &scaron;iroko rasprostranjeni flavonoid koji inhibi&scaron;e različite metaboličke puteve i na taj način može usporiti metabolizam i eliminaciju i povećati koncentraciju lekova u krvi. Ciljevi ovog istraživanja su bili da se ispita da li apigenin i natrijum-deoksiholat mogu povećati bioraspoloživost raloksifena, njihov uticaj na biohemijske parametre i parametre hemostaze, kao i da se ispita antioksidativni potencijal apigenina. Ispitan je i uticaj apigenina na akutno o&scaron;tećenje jetre usled primene toksične doze paracetamola. U istraživanju su kori&scaron;ćeni zdravi, beli pacovi mu&scaron;kog roda, soja Wistar. U ogledu su ukupno kori&scaron;ćene 84 eksperimentalne životinje. Sva ispitivanja na životinjama je odobrila Etička komisija Univerziteta u Novom Sadu. Raloksifen je primenjen intravenski i per os, dok su natrijum-deoksiholat i apigenin aplikovani peroralno. Uzorci krvi, urina i fecesa su kori&scaron;ćeni za određivanje farmakokinetskih parametara, dok su za određivanje biohemijskih, hemostatskih i parametara oksidativnog stresa kori&scaron;ćeni serum i uzorci jetre laboratorijskih životinja. Pretretman natrijum-deoksiholatom je doveo do smanjenja koncentracije raloksifena u krvi zbog olak&scaron;anog i brzog prodora raloksifena u periferne kompartmane. Time je značajno produženo poluvreme eliminacije i srednje vreme zadržavanja raloksifena i značajno je povećan volumen distribucije raloksifena. Apigenin je doveo do manjeg pada koncentracije raloksifena u prvim satima nakon intravenske primene raloksifena, dok su koncentracije raloksifena bile značajno vi&scaron;e nakon osmog časa od primene leka. Uticaj raloksifena na biohemijske parametre je bio značajno veći nakon intravenske nego nakon peroralne primene. Nakon intravenske primene raloksifena je značajno povećana aktivnost enzima jetre, ALP, ALT, AST i GGT, dok su pokazatelji funkcije bubrega, urea, mokraćna kiselina i kreatinin bili sniženi. U grupama koje su pretretirane natrijum-deoksiholatom i apigeninom vrednosti ovih parametara bile su niže u odnosu na grupu tretiranu samo raloksifenom. Statistički najznačajniji uticaj je imala primena trojne kombinacije, raloksifena, natrijum-deosiholata i apigenina, koja je dovela do značajnog pada aktivnosti enzima jetre, i u odnosu na grupu tretiranu raloksifenom i u odnosu na kontrolnu grupu. Kod životinja tretiranih kombinacijom apigenina i paracetamola pokazatelji toksičnosti su bili značajno niži, naročito vrednosti ALT i ALP, u odnosu na grupu koja je dobijala samo paracetamol. Hepatotoksičnost izazvana toksičnom dozom paracetamola je potvrđena i histopatolo&scaron;kim promenama na jetri, koje nisu primećene u grupi životinja tretiranih kombinacijom apigenina i paracetamola. Ispitivanjem je utvrđeno da apigenin može da spreči paracetamolom indukovano povećanje nivoa MDA, &scaron;to ukazuje da apigenin pozitivno utiče na očuvanje integriteta ćelije. Aktivnost enzima CAT i GR u homogenatima jetre je bila značajno povećana nakon primene toksične doze paracetamola u odnosu na kontrolnu grupu. Aktivnost enzima CAT i GR u grupi tretiranoj kombinacijom apigenina i paracetamola je bila približna vrednostima u kontrolnoj grupi. Na osnovu rezultata istraživanja može se zaključiti da natrijum-deoksiholat i apigenin značajno utiču na farmakokinetiku raloksifena. Primena natrijum-deoksiholata dovela je do pada koncentracije raloksifena u krvi, značajnog prelaska raloksifena iz krvi u periferne kompartmane i povećanja njegovog volumena distribucije, dok je apigenin značajno usporio metabolizam i eliminaciju raloksifena i doveo do njegovog produženog zadržavanja u krvi. Natrijum-deoksiholat i apigenin su pokazali pozitivan uticaj na biohemijske parametre, parametre hemostaze i smanjenje nivoa oksidativnog stresa. Kombinacija natrijum-deoksiholata i apigenina je pokazala sinergistički uticaj na navedene parametre, odnosno dovela je do značajnih promena u odnosu na pojedinačnu primenu ovih supstanci. Rezultati ispitivanja ukazuju na to da apigenin smanjuje stepen lipidne peroksidacije i da dovodi do značajnog povećanja enzimskih antioksidantnih mehanizama odbrane kod pacova kod kojih je hepatotoksičnost indukovana paracetamolom.</p> / <p>Raloxifene is selective estrogen receptor modulator used in treatment of osteoporosis and invasive breast cancer in postmenopausal women. Raloxifene is well absorbed from the gastrointestinal tract, but undergoes extensive first-pass metabolism, which results in very low bioavailability of raloxifene, 2% in humans, and 39% in Wistar rats. Various supstances are used for increasing bioavailability of other drugs. Bile acids, such as deoxycholic acid, promote transport of other supstances through biological membranes, and consequently, may increase their bioavailability. Apigenin is a widespread flavonoid, which inhibits different metabolic pathways. Thus, apigenin can slow down metabolism and elimination of drugs, and raise drug concentration in blood. Aims of this study were to investigate if apigenin and sodium deoxycholate could increase bioavailability of raloxifene, their influence on biochemical and hemostasis parameters, and to investigate antioxidative potential of apigenin. Furthermore, influence of apigenin on acute liver damage after toxic dose of paracetamol was examined. In vivo experiments were performed on 84 laboratory healthy male Wistar rats. All experiments were approved by Ethics Committee of University of Novi Sad. Raloxifene was applied intravenously and per os, while sodium deoxycholate and apigenin were given perorally. Blood, urine and feces samples were used for pharmacokinetic parameters measurement, whereas serum and liver samples were used for evaluation of biochemical, hemostasis and oxidative stress parameters. Pretreatment of sodium deoxycholate led to raloxifene blood concentration decrease due to easier penetration of raloxifene in peripher compartments. As a result, raloxifene half-life and mean residence time were significantly longer and volume of distribution was increased. Apigenin caused lower decrease in raloxifene concentration in first few hours after raloxifene intravenous application, while raloxifene concentrations after apigenin pretreatment were significantlny higher 8 hours after raloxifene application. Influence of raloxifene on biochemical parameters was more significant after intravenous than after per os application. Intravenous application of raloxifene led to increased activity of liver enzymes, ALP, ALT, AST and GGT, while parameters of kidney function, urea, uric acid and creatinine were decreased in comparison to the control group. In experimental groups pretreated with sodium deoxycholate and apigenin these parameters were lower than in the group treated only with raloxifene. Statistically the most significant effects were in the group treated with combination of raloxifene, sodium deoxycholate and apigenin, which caused significant decrease in activity of liver enzymes compared both with raloxifene and control group of animals. In experimental animals treated with combination of apigenin and paracetamol bioindicators of paracetamol toxicity were significantly lower, especially activity of ALT and ALP, in comparison to the group treated only with paracetamol. Hepatotoxicity induced by toxic dose of paracetamol was also confirmed by histopathological alterations in liver, which were not observed in the experimental group treated with combination of apigenin and paracetamol. In this study it was confirmed that apigenin could prevent paracetamol-induced MDA level increase, which suggests that apigenin have positive effects on cell integrity. Activity of CAT and GR in liver homogenates was significantly increased after toxic dose of paracetamol in comparison to the control group, while activity of these enzymes in the group treated with apigenin and paracetamol was similar to values in the control group. Results of this study showed that sodium deoxycholate and apigenin can significantly change pharmacokinetic parameters of raloxifene. Sodium deoxycholate caused signicant decrease in raloxifene blood concentration, extensive distribution from blood to peripheral compartments and increase of raloxifene volume of distribution. Apigenin inhibited metabolism and elimination of raloxifene and thus prolonged half-life and mean residence time of raloxifene. Sodium deoxycholate and apigenin showed positive effects on biochemical and hemostasis parameters and decreased the level oxidative stress. Combination of sodium deoxycholate and apigenin showed synergistic effects on these parameters in comparison to effects of separate application of sodium deoxycholate and apigenin. The result of our study indicates that apigenin inhibits the level of lipid peroxidation and significantly increase the enzyme antioxidant defence mehanisms in paracetamol induced hepatotoxicity in rats.</p>