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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The acute effects of two different training models on markers of inflammatory activation and skeletal muscle injury in patients with chronic heart failure

Taylor, Arlana 11 1900 (has links)
Background: Patients with heart failure (HF) are characterized by exercise intolerance, breathlessness, fatigue and excessive neurohormonal activation associated with premature mortality. Recently, inflammatory activation has been described as an important factor in the progression of HF. Increased levels of certain pro-inflammatory cytokines (e.g., TNF-ɑ, IL-6) have been related to increased severity of left ventricular dysfunction, the activation of the sympathetic and renin-angiotensin systems and the catabolism of skeletal muscle. Although exercise training is important in the management of HF, acute bouts of exercise may lead to increases in proinflammatory cytokines. It is believed that the skeletal muscle abnormalities associated with HF may increase the risk of damage to skeletal muscle, (i.e., exercise-induced muscle injury (EIMI) with associated inflammatory activation) especially following unaccustomed exercise training. Recently, several training methods have been proposed for patients with HF that challenge the traditional “steady-state” (SS) training model, including interval training (IT). Interval training methods employ greater muscular loading than SS and therefore may increase the risk of inflammatory system activation EIMI, and/or reduced muscle function. There is no study that has examined the effects of IT on EIMI, muscle function and/or inflammatory markers. Material and Methods: Fourteen male participants with HF (mean age: 59 +/- 7.8 yrs; mean VO2 peak: 13.64 +/- 4.5 ml/kg/m-1; EF < 45%) were matched (for body mass and aerobic fitness) and randomized into SS or IT for 20 minutes. The IT involved 2 minute work:recovery phases of 90% and 40% of heart rate reserve, respectively. The SS involved continuous exercise at 65% of heart rate reserve. Biochemical markers of muscle damage and acute inflammation, concentric and eccentric isokinetic muscle torque, and subjective indicators of delayed onset muscle soreness (DOMS) and lower extremity function were evaluated at baseline, and then immediately following the training bout, and at 6, 24, and 48 hours post. Results: There were no significant differences between the IT and the SS training group for markers of skeletal muscle injury or inflammatory activation. Conclusions: The findings from the present study suggest that IT or SS do not result in excessive inflammatory system activation or skeletal muscle injury. These results have important implications for clinicians prescribing exercise regimes for HF patients who may be starting back into activity after a prolonged sedentary period. Additionally, results from this study indicate that there is a need for future research looking at the actual and perceived effect of even a single about of exercise on lower extremity function.
2

The acute effects of two different training models on markers of inflammatory activation and skeletal muscle injury in patients with chronic heart failure

Taylor, Arlana 11 1900 (has links)
Background: Patients with heart failure (HF) are characterized by exercise intolerance, breathlessness, fatigue and excessive neurohormonal activation associated with premature mortality. Recently, inflammatory activation has been described as an important factor in the progression of HF. Increased levels of certain pro-inflammatory cytokines (e.g., TNF-ɑ, IL-6) have been related to increased severity of left ventricular dysfunction, the activation of the sympathetic and renin-angiotensin systems and the catabolism of skeletal muscle. Although exercise training is important in the management of HF, acute bouts of exercise may lead to increases in proinflammatory cytokines. It is believed that the skeletal muscle abnormalities associated with HF may increase the risk of damage to skeletal muscle, (i.e., exercise-induced muscle injury (EIMI) with associated inflammatory activation) especially following unaccustomed exercise training. Recently, several training methods have been proposed for patients with HF that challenge the traditional “steady-state” (SS) training model, including interval training (IT). Interval training methods employ greater muscular loading than SS and therefore may increase the risk of inflammatory system activation EIMI, and/or reduced muscle function. There is no study that has examined the effects of IT on EIMI, muscle function and/or inflammatory markers. Material and Methods: Fourteen male participants with HF (mean age: 59 +/- 7.8 yrs; mean VO2 peak: 13.64 +/- 4.5 ml/kg/m-1; EF < 45%) were matched (for body mass and aerobic fitness) and randomized into SS or IT for 20 minutes. The IT involved 2 minute work:recovery phases of 90% and 40% of heart rate reserve, respectively. The SS involved continuous exercise at 65% of heart rate reserve. Biochemical markers of muscle damage and acute inflammation, concentric and eccentric isokinetic muscle torque, and subjective indicators of delayed onset muscle soreness (DOMS) and lower extremity function were evaluated at baseline, and then immediately following the training bout, and at 6, 24, and 48 hours post. Results: There were no significant differences between the IT and the SS training group for markers of skeletal muscle injury or inflammatory activation. Conclusions: The findings from the present study suggest that IT or SS do not result in excessive inflammatory system activation or skeletal muscle injury. These results have important implications for clinicians prescribing exercise regimes for HF patients who may be starting back into activity after a prolonged sedentary period. Additionally, results from this study indicate that there is a need for future research looking at the actual and perceived effect of even a single about of exercise on lower extremity function.
3

The acute effects of two different training models on markers of inflammatory activation and skeletal muscle injury in patients with chronic heart failure

Taylor, Arlana 11 1900 (has links)
Background: Patients with heart failure (HF) are characterized by exercise intolerance, breathlessness, fatigue and excessive neurohormonal activation associated with premature mortality. Recently, inflammatory activation has been described as an important factor in the progression of HF. Increased levels of certain pro-inflammatory cytokines (e.g., TNF-ɑ, IL-6) have been related to increased severity of left ventricular dysfunction, the activation of the sympathetic and renin-angiotensin systems and the catabolism of skeletal muscle. Although exercise training is important in the management of HF, acute bouts of exercise may lead to increases in proinflammatory cytokines. It is believed that the skeletal muscle abnormalities associated with HF may increase the risk of damage to skeletal muscle, (i.e., exercise-induced muscle injury (EIMI) with associated inflammatory activation) especially following unaccustomed exercise training. Recently, several training methods have been proposed for patients with HF that challenge the traditional “steady-state” (SS) training model, including interval training (IT). Interval training methods employ greater muscular loading than SS and therefore may increase the risk of inflammatory system activation EIMI, and/or reduced muscle function. There is no study that has examined the effects of IT on EIMI, muscle function and/or inflammatory markers. Material and Methods: Fourteen male participants with HF (mean age: 59 +/- 7.8 yrs; mean VO2 peak: 13.64 +/- 4.5 ml/kg/m-1; EF < 45%) were matched (for body mass and aerobic fitness) and randomized into SS or IT for 20 minutes. The IT involved 2 minute work:recovery phases of 90% and 40% of heart rate reserve, respectively. The SS involved continuous exercise at 65% of heart rate reserve. Biochemical markers of muscle damage and acute inflammation, concentric and eccentric isokinetic muscle torque, and subjective indicators of delayed onset muscle soreness (DOMS) and lower extremity function were evaluated at baseline, and then immediately following the training bout, and at 6, 24, and 48 hours post. Results: There were no significant differences between the IT and the SS training group for markers of skeletal muscle injury or inflammatory activation. Conclusions: The findings from the present study suggest that IT or SS do not result in excessive inflammatory system activation or skeletal muscle injury. These results have important implications for clinicians prescribing exercise regimes for HF patients who may be starting back into activity after a prolonged sedentary period. Additionally, results from this study indicate that there is a need for future research looking at the actual and perceived effect of even a single about of exercise on lower extremity function. / Education, Faculty of / Kinesiology, School of / Graduate
4

REHABILITATIVE INFLUENCE OF THERAPEUTIC ULTRASOUND TREATMENT ON CELLULAR MARKERS OF SKELETAL MUSCLE REGENERATION FOLLOWING BLUNT CONTUSION INJURY

Wilkin, Linda D. 11 September 2002 (has links)
No description available.
5

Efeitos da associação dos tratamentos de crioterapia e ultrassom terapêutico na reparação da lesão muscular de ratos wistar / Effects of the association of cryotherapy and therapeutic ultrasound in the repair of muscle injury of Wistar rats

Koike, Tatiana Emy [UNESP] 17 February 2016 (has links)
Submitted by TATIANA EMY KOIKE null (tatikoike@yahoo.com) on 2016-03-10T11:09:02Z No. of bitstreams: 1 Encadernaçao Mestrado UNESP- Tatiana Emy Koike.pdf: 1535953 bytes, checksum: 25ca75a268f1c6bf7d7ca80e833b9cbd (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-03-10T20:19:49Z (GMT) No. of bitstreams: 1 koike_te_me_prud.pdf: 1535953 bytes, checksum: 25ca75a268f1c6bf7d7ca80e833b9cbd (MD5) / Made available in DSpace on 2016-03-10T20:19:49Z (GMT). No. of bitstreams: 1 koike_te_me_prud.pdf: 1535953 bytes, checksum: 25ca75a268f1c6bf7d7ca80e833b9cbd (MD5) Previous issue date: 2016-02-17 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Muscle injuries are often cause due to the practice of sports and recreational activities. Because of its high incidence, it is important to research the treatments that promote quality in the muscle and shorter repair process. To evaluate the effect of the combination of the therapeutic resources of Cryotherapy and Therapeutic Ultrasound in the treatment of muscle damage by impact. 55 Wistar rats was separate into groups, Acute Injury (AI), Injury (I), Cryotherapy (CR), Therapeutic Ultrasound (TU), Cryotherapy and Therapeutic Ultrasound (CRTU). All animals were anesthetize and muscle damage due to impact by the release of a load of 200 g at 30 cm. Then received treatments as allocated group and CR protocol using ice bag for 20 minutes and TU for five minutes with an intensity of 0.5W / cm2 and the frequency of 1MHz. Euthanasia was performed by intraperitoneal administration of overdose of Xylazine and Ketamine. The collection of the gastrocnemius muscle for the Body and Muscle mass analysis, histological analysis and fractal dimension of inflammation and collagen gene quantification of mRNA (TNF-α and TGF-β1). Data analysis was performed using SPSS for Windows 22. The Shapiro-Wilk test to verify the normality of the data was performed. When data showed normal, we used t test for paired samples test and one-way ANOVA followed by Tukey’s post-test. When it violated the normality of the data, followed by the Kruskal- Wallis test with Dunn’s post-test. For all analyzes was adopted the significance level of 5%. Among all groups, the CRTU lose less body and muscle mass, improved morphometry, besides presenting collagen reduction by DF compared to AI and CR (p <0.05). With regard to the inflammatory process CRTU group showed a significant reduction of DF in relation to the AI groups (p = 0.001), I (p = 0.001) and CR (p = 0.007), and TU reduced the DF significantly relative to AI groups (p = 0.001), I (p = 0.001) and CR (p = 0.036). The reduction of TNF-α was significant in TU group compared with AI groups (p = 0.008); I (p = 0.032) and CR (p = 0.046) and TGF- β1 in the CR group compared to AI (p = 0.001) and I (p = 0.006), in the TU group compared to AI (p = 0.049) and CRTU compared to AI (p = 0.023). The combination treatment was superior to the results presented by the isolated treatments in the muscle repair process. Observed by reducing the loss of body and muscle mass, improved histological appearance and reduction of collagen. / As lesões musculares são frequentemente ocasionadas em decorrência da prática de atividades esportivas e recreativas. Devido sua alta incidência, é importante pesquisar os tratamentos que promovam qualidade no processo de reparação muscular e menor duração. Avaliar o efeito da combinação dos recursos terapêuticos de Crioterapia e Ultrassom Terapêutico no tratamento de lesão muscular por impacto. 55 ratos wistar foram separados em Grupos Lesão Aguda (LA), Lesão (L), Crioterapia (CR), Ultrassom Terapêutico (US), Crioterapia e Ultrassom Terapêutico (CRUS). Todos os animais foram anestesiados e submetidos à lesão muscular por impacto pela liberação de uma carga de 200g a 30 cm de altura. Em seguida receberam os tratamentos conforme grupo alocado, sendo o protocolo de CR por meio de bolsa de gelo durante 20 minutos e o US durante cinco minutos com intensidade de 0,5W/cm2 e frequência de 1MHz. A eutanásia foi realizada por administração intraperitoneal de superdosagem de Xilazina e Ketamina, para subsequente coleta do músculo gastrocnêmio destinado às análises de massa Corporal e Muscular, análises Histológica e Dimensão Fractal do processo inflamatório e de colágeno, Quantificação gênica de RNAm (TNF-α e TGF-β1). A análise dos dados foi realizada utilizando o programa estatístico SPSS 22 for Windows. Foi realizado o teste de Shapiro-Wilk para verificação da normalidade dos dados. Quando os dados apresentaram normalidade, foi utilizado teste T para amostras pareadas e teste de Anova one-way, seguido pelo pós-teste de Tukey. Quando violada a normalidade dos dados, seguiu-se com o teste de Kruskall-Wallis, com pós-teste de Dunn. Para todas as análises foi adotado o nível de significância de 5%. Dentre todos os grupos, o CRUS perdeu menos massa corporal e muscular, melhora da morfometria, além de apresentar redução de colágeno pela DF em comparação aos LA e CR (p < 0,05). Com relação ao processo inflamatório, grupo CRUS apresentou redução significante da DF em relação aos grupos LA (p = 0,001), L (p = 0,001) e CR (p = 0,007), e o US reduziu a DF significativamente em relação aos grupos LA (p = 0,001), L (p = 0,001) e CR (p = 0,036). A redução de TNF-α foi significante no grupo US comparado com grupos LA (p = 0,008); L (p = 0,032) e CR (p = 0,046), e TGF-β1 no grupo CR em comparação aos LA (p = 0,001) e L (p = 0,006), no grupo US em comparação ao LA (p = 0,049), e CRUS em comparação aos LA (p = 0,023). A associação de tratamentos foi superior aos resultados apresentados pelos tratamentos isolados no processo de reparação muscular. Observado pela redução da perda de massa corporal e muscular, melhora do aspecto histológico e redução de colágeno.
6

Repair of skeletal muscle transection injury with tissue loss

Merritt, Edward Kelly, 1979- 19 October 2009 (has links)
A traumatic skeletal muscle injury that involves the loss of a substantial portion of tissue will not regenerate on its own. Little is understood about the ability of the muscle to recover function after such a defect injury, and few research models exist to further elucidate the repair and regeneration processes of defected skeletal muscle. In the current research, a model of muscle injury was developed in the lateral gastrocnemius (LGAS) of the rat. In this model, the muscle gradually remodels but functional recovery does not occur over 42 days. Repair of the defect with muscle-derived extracellular matrix (ECM), improves the morphology of the LGAS. Blood vessels and myofibers grow into the ECM implant in vivo, but functional recovery does not occur. Addition of bone marrow-derived mesenchymal stem cells (MSCs) to the implanted ECM in the LGAS increases the number of blood vessels and regenerating myofibers within the ECM. Following 42 days of recovery, the cell-seeded ECM implanted LGAS produces significantly higher isometric force than the non-repaired and non-cell seeded ECM muscles. These results suggest that the LGAS muscle defect is a suitable model for the study of traumatic skeletal muscle injury with tissue loss. Additionally, MSCs seeded on an implanted ECM lead to functional restoration of the defected LGAS. / text
7

Avaliação estrutural, estereológica e biomecânica do efeito da aplicação do ultrassom no reparo da lesão lacerativa experimental do gastrocnêmio de rato / Biomechanical, stereological and structural assessment of the ultrasound effect on the repair of muscle injury in rats

Piedade, Maria Cristina Balejo 08 October 2010 (has links)
O objetivo deste estudo foi avaliar os efeitos do ultrassom pulsado (USp) no reparo muscular em um modelo experimental de lesão lacerativa do músculo gastrocnêmio medial em ratos Wistar. Vinte ratos foram tratados diariamente com USp (50%), 1MHz, 0,57W/cm² de intensidade por 5 min. formando os grupos tratados (GT), e 20 animais constituíram os grupos controle (CG). A análise histológica, morfométrica (usando o método estereológico) e biomecânica (teste de tensão) foi realizada aos 4, 7, 14 e 24 dias após a lesão. As lesões apresentaram um padrão de reparo similar tanto nos GT como nos GC. Os volumes absolutos da lesão (VL) e das zonas central e de regeneração (VZC e VZR) diminuíram progressivamente ao longo do processo de reparo tanto nos GT como nos GC. No GT, o VL diminuiu significativamente em todos os dias experimentais, sendo que VZC uma diminuição significante aos 4 e 7 dias pós-lesão e o VZR aos 14 dias pós-lesão. A fração de volume de vasos sanguíneos e a fração de superfície de vasos sanguíneos foi maior nos GT aos 4 e 7 dias pós-lesão em relação aos respectivos controles. Apesar de haver uma tendência a um maior volume absoluto de vasos sanguíneos nos GT, a análise estatística mostrou que existe uma maior volume de vasos somente aos 4 dias pós-lesão. Não houve diferença significante na área de superfície total de vasos sanguíneos na lesão quando se comparam os grupos entre si. Houve um aumento significante na fração de volume de fibras de colágeno na lesão nos GT aos 4,7 e 14 dias pós-lesão. Houve um aumento significante na tensão máxima e na rigidez nos GT aos 4 e 24 dias após a lesão. Não houve diferença significante na deformação relativa entre GC e GT. Os resultados sugerem que o USp otimiza a fase inflamatória e estimula as fases proliferativa e de remodelamento, promovendo uma diminuição mais acentuada no volume da lesão, estimulando a angiogênese, assim como, a deposição e a organização do colágeno fibrilar. Os achados histológicos corroboram com os achados biomecânicos, que mostram que os músculos tratados pelo USp tiveram propriedades biomecânicas mais parecidas com as do músculo íntegro / The aim of this study was to evaluate the effect of the pulsed ultrasound therapy (PUT) in stimulating muscle repair in an experimental model of lacerative gastrocnemius medialis muscle lesion in 40 Wistar rats. Twenty rats were treated (TG) daily with 1MHz pulsed ultrasound (50%) at 0.57W/cm² for 5 min, and 20 were control animals (CG). Muscle samples were harvested up on postoperative days 4, 7, 14 and 24 for stereological, histological, and biomechanical analyses. The lesions presented similar repair pattern in both TG and CG. The lesion volume (VL) and the central and regenerative zones volumes (VCZ and VRZ) had a progressive deacrease through the post lesion period both in the TG and CG. The VL decrease was significantly greater in the TG in all experimental days, the VCZ decrease was significant in the TG at 4 and 7 days post lesion, and the VRZ decrease was significant at 14 days post lesion in the TG. Statistically significant increase was found in the blood vessels volume fraction and in the surface fraction of blood vessels in the TG at 4 and 7 days post lesion compared to respective CG. Although there was a tendency to have a greater blood vessels absolute volume within lesion in the TG, the statistical analysis showed that it was only larger at 4 days after surgery in US treated group. No statistically significant increase was found in the surface total area within lesion in all experimental days between CG and TG. There was a significant increase in the volume fraction of fibrilar collagen within the lesion in the TG at 4, 7 and 14 days post lesion. The biomechanical data showed a significant increase in the maximal stress and stiffness in the TG at 4 and 24 days after lesion, although there was a progressive increase of these variables both in the CG and TG. There was no significant difference in the maximal elongation, between CG and TG. Our data suggest that the PUT acts as an inflammatory optimizer and stimulates the proliferative and remodeling phases, promoting a greater decrease in the VL and in the VCZ, stimulating angiogenesis and controlling fibrilar collagen deposition and organization in this experimental model of lacerative gastrocnemius muscle lesion. The histological data are in accordance to the biomechanical data, which shows that the muscles treated by USp have biomechanical properties similar to the noninjuried muscles
8

An immunohistochemical analysis of regenerating cellular material in two distinct models of skeletal muscle injury

Sarathy, Apurva 14 November 2011 (has links)
Tourniquet mediated Ischemia Reperfusion (I/R) injury causes damage to skeletal muscle, often resulting in prolonged functional impairment. The current study utilizes immunohistochemistry (IHC) to determine whether the controlled release of the anabolic factor, insulin-like growth factor-I (IGF-I), from the biodegradable PEGylated fibrin gel matrix can facilitate the recovery of skeletal muscle from I/R. Treatment groups following a 2-hour tourniquet applied to the limb of 6-9 month rats, included intramuscular injections of saline, PEGylated fibrin gel (PEG-Fib) only and IGF-I conjugated to PEGylated fibrin gel (PEG-Fib-IGF). Expression of the myogenic regulatory factors MyoD and myogenin detected via IHC in the PEG-Fib-IGF group was significantly lower compared to the saline group, showing a 1.4±0.8% nuclear co-localization for MyoD and a 2.0±0.8% nuclear co-localization for myogenin at 14 days of recovery. The saline group showed higher values, 31.4±4.4% and 44.1±7.3% for MyoD and myogenin nuclear co-localization respectively. A significantly greater percentage, 88.8±3.7% of Desmin positive myofibers was seen at 14 days of recovery, while a lower percentage of fibers expressing neonatal myosin, 7.7±2.7% was seen in the PEG-Fib-IGF group compared to the saline treatment group. These results indicate that IGF-I delivered intramuscularly via PEGylated fibrin gel, functions therapeutically in skeletal muscle recovery, from I/R mediated damage. In a separate injury model that deals with volumetric muscle loss, IHC analyses were performed to test the efficacy of a novel tissue engineering strategy utilizing extracellular matrix (ECM) as a scaffold. In this model, also called the defect model, a 1.0 X 1.0 cm piece of the lateral gastrocnemius was removed and replaced with a muscle-derived ECM. The constructs were then seeded with bone marrow derived cells (BMSCs), adipose derived stem cells (ADSCs) or the peroneal nerve was relocated to the area of the ECM implant. 42 days post recovery IHC analysis was performed on the ECM implants. The quantification of desmin-positive regenerating myofibers bearing centrally located nuclei, showed significantly greater values in the top, middle and bottom region of the ECM implants that received peroneal nerve relocation, when compared to the experimental group that received the ECM implant alone. Blood vessel density increases were seen within the middle region of the ECM implant groups that received BMSC+Nerve treatment and the bottom region of the ECM implant groups that received ADSC+Nerve treatment. Thus, these results corroborate the therapeutic effect of peroneal nerve relocation, which stimulated an increase in myofiber regeneration and vascular maintenance within the construct. / text
9

Avaliação estrutural, estereológica e biomecânica do efeito da aplicação do ultrassom no reparo da lesão lacerativa experimental do gastrocnêmio de rato / Biomechanical, stereological and structural assessment of the ultrasound effect on the repair of muscle injury in rats

Maria Cristina Balejo Piedade 08 October 2010 (has links)
O objetivo deste estudo foi avaliar os efeitos do ultrassom pulsado (USp) no reparo muscular em um modelo experimental de lesão lacerativa do músculo gastrocnêmio medial em ratos Wistar. Vinte ratos foram tratados diariamente com USp (50%), 1MHz, 0,57W/cm² de intensidade por 5 min. formando os grupos tratados (GT), e 20 animais constituíram os grupos controle (CG). A análise histológica, morfométrica (usando o método estereológico) e biomecânica (teste de tensão) foi realizada aos 4, 7, 14 e 24 dias após a lesão. As lesões apresentaram um padrão de reparo similar tanto nos GT como nos GC. Os volumes absolutos da lesão (VL) e das zonas central e de regeneração (VZC e VZR) diminuíram progressivamente ao longo do processo de reparo tanto nos GT como nos GC. No GT, o VL diminuiu significativamente em todos os dias experimentais, sendo que VZC uma diminuição significante aos 4 e 7 dias pós-lesão e o VZR aos 14 dias pós-lesão. A fração de volume de vasos sanguíneos e a fração de superfície de vasos sanguíneos foi maior nos GT aos 4 e 7 dias pós-lesão em relação aos respectivos controles. Apesar de haver uma tendência a um maior volume absoluto de vasos sanguíneos nos GT, a análise estatística mostrou que existe uma maior volume de vasos somente aos 4 dias pós-lesão. Não houve diferença significante na área de superfície total de vasos sanguíneos na lesão quando se comparam os grupos entre si. Houve um aumento significante na fração de volume de fibras de colágeno na lesão nos GT aos 4,7 e 14 dias pós-lesão. Houve um aumento significante na tensão máxima e na rigidez nos GT aos 4 e 24 dias após a lesão. Não houve diferença significante na deformação relativa entre GC e GT. Os resultados sugerem que o USp otimiza a fase inflamatória e estimula as fases proliferativa e de remodelamento, promovendo uma diminuição mais acentuada no volume da lesão, estimulando a angiogênese, assim como, a deposição e a organização do colágeno fibrilar. Os achados histológicos corroboram com os achados biomecânicos, que mostram que os músculos tratados pelo USp tiveram propriedades biomecânicas mais parecidas com as do músculo íntegro / The aim of this study was to evaluate the effect of the pulsed ultrasound therapy (PUT) in stimulating muscle repair in an experimental model of lacerative gastrocnemius medialis muscle lesion in 40 Wistar rats. Twenty rats were treated (TG) daily with 1MHz pulsed ultrasound (50%) at 0.57W/cm² for 5 min, and 20 were control animals (CG). Muscle samples were harvested up on postoperative days 4, 7, 14 and 24 for stereological, histological, and biomechanical analyses. The lesions presented similar repair pattern in both TG and CG. The lesion volume (VL) and the central and regenerative zones volumes (VCZ and VRZ) had a progressive deacrease through the post lesion period both in the TG and CG. The VL decrease was significantly greater in the TG in all experimental days, the VCZ decrease was significant in the TG at 4 and 7 days post lesion, and the VRZ decrease was significant at 14 days post lesion in the TG. Statistically significant increase was found in the blood vessels volume fraction and in the surface fraction of blood vessels in the TG at 4 and 7 days post lesion compared to respective CG. Although there was a tendency to have a greater blood vessels absolute volume within lesion in the TG, the statistical analysis showed that it was only larger at 4 days after surgery in US treated group. No statistically significant increase was found in the surface total area within lesion in all experimental days between CG and TG. There was a significant increase in the volume fraction of fibrilar collagen within the lesion in the TG at 4, 7 and 14 days post lesion. The biomechanical data showed a significant increase in the maximal stress and stiffness in the TG at 4 and 24 days after lesion, although there was a progressive increase of these variables both in the CG and TG. There was no significant difference in the maximal elongation, between CG and TG. Our data suggest that the PUT acts as an inflammatory optimizer and stimulates the proliferative and remodeling phases, promoting a greater decrease in the VL and in the VCZ, stimulating angiogenesis and controlling fibrilar collagen deposition and organization in this experimental model of lacerative gastrocnemius muscle lesion. The histological data are in accordance to the biomechanical data, which shows that the muscles treated by USp have biomechanical properties similar to the noninjuried muscles

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