Analysis of motor performance and histomorphometry of skeletal muscles of rats exercised after cerebral ischemia.

INTRODUCTION: Cerebral ischemia causes muscle atrophy and motor incoordination in animals, impairing motor performance. OBJECTIVE: Thus, the objective of the present study was to analyze the motor performance and histomorphometry of the biceps brachii, soleus, and anterior tibialis muscles of rats submitted to a treadmill training program after induction of cerebral ischemia by the transient occlusion of the middle cerebral artery (MCAO). MATERIALS AND METHODS: To do so, twenty-four 30-day-old Wistar rats were utilized. The exercises were performed for 6 weeks on a leveled treadmill, for 30 min/day, 5 days a week, at a controlled speed of 8 m/min, and the MCAO surgery took place for 60 min. The animals were divided into the following experimental groups: SC (n = 6): control animals that underwent false surgery (operation without the induction of cerebral ischemia) and did not exercise (sedentary); CEA (n = 6): control animals exercised on the treadmill after the false surgery; SI (n = 6): sedentary ischemic animals; IEA (n = 6): animals exercised on the treadmill after the induction of cerebral ischemia. RESULTS: The type-II fibers atrophy in muscle soleo was observed in groups CEA (5125.63 ± 158.83) and SI (4982.38 ± 248.16) when compared to the SC (5927.98 ± 106.17) and IEA (6526.73 ± 195.08) groups. CONCLUSION: It is concluded that the low intensity physical exercise performed on the treadmill for six weeks after the induction of cerebral ischemia by OMCA, promoted a decrease in the atrophy of muscles important of the ischemic animals, benefiting their motor performance.

Diferenciação de células-tronco mesenquimais derivadas do tecido adiposo em cardiomiócitos / Differentiation of adipose tissue-derived mesenchymal stem cells into cardiomyocytes

FUNDAMENTO: O potencial de renovação e proliferação dos cardiomiócitos, in vivo, é pequeno, e por isso, o músculo cardíaco apresenta limitada capacidade de repor células perdidas. Na tentativa de minimizar os danos oriundos de lesões hipóxico-isquêmicas e daquelas que acometem o sistema de condução do coração, a terapia celular com células-tronco mesenquimais (MSC) vem sendo utilizada, inclusive com cardiomiócitos diferenciados a partir de MSC. OBJETIVO: O presente trabalho comparou três protocolos distintos de indução de diferenciação objetivando a sugestão de um método viável para a diferenciação de maior número de células funcionais que expressem fenótipo cardiomiogênico. MÉTODOS: Culturas de MSC obtidas de tecido adiposo de ratos jovens da linhagem Lewis transgênicos para proteína verde fluorescente (GFP) foram submetidos a três diferentes meios de diferenciação cardiogênica: Planat-Bérnard, 5-azacitidina e meio Planat-Bérnard + 5-azacitidina e observadas quanto a expressão de marcadores celulares cardíacos. RESULTADOS: Nos três protolocos utilizados observou-se formação da proteína alfa-actinina sarcomérica no citoesqueleto das células submetidas à diferenciação, expressão de conexina 43 na membrana nuclear e citoplasmática e formação de gap junctions, necessárias para a propagação do impulso elétrico no miocárdio, contudo, em nenhum protocolo foi observada contração espontânea das células submetidas à diferenciação cardiogênica. CONCLUSÃO: A indução com 5-azacitidina proporcionou diferenciação celular cadiomiogênica efetiva e similar à encontrada com o meio Planat-Bénard e, por ser um protocolo mais simples, rápido e com menor custo torna-se o método de eleição.

BACKGROUND: Cardiomyocytes have small potential for renovation and proliferation in vivo. Consequently, the heart muscle has limited capacity of self-renewal. Mesenchymal stem cells (MSC) therapy, as well as MSC differentiated into cardiomyocytes, has been used in the attempt to minimize the effects of ischemic-hypoxic lesions and those affecting the electrical conduction system of the heart. OBJECTIVE: The present study compared three distinct protocols for induced differentiation of MSC into cardiomyocytes aimed at finding a viable method for producing a large number of functional cells expressing cardiomyogenic phenotype. METHODS: Mesenchymal stem cells were obtained from the adipose tissue of young transgenic Lewis rats expressing green fluorescent protein (GFP), and submitted to three distinct differentiation-inducing media: 1) Planat-Bérnard, 2) 5-azacytidine, and 3) Planat-Bérnard + 5-azacytidine; further, these cells were identified based on the expression of cardiac cell markers. RESULTS: All three protocols detected the expression of sarcomeric-alpha-actinin protein in the exoskeleton of cells, expression of connexin-43 in the nuclear and cytoplasmic membrane, and formation of gap junctions, which are necessary for electrical impulse propagation in the myocardium. However, no spontaneous cell contraction was observed with any of the tested protocols. CONCLUSION: Induction with 5-azacytidine provided an effective cadiomyogenic cellular differentiation similar to that obtained with Planat-Bénard media. Therefore, 5-azacytidine was the method of choice for being the simplest, fastest and lowest-cost protocol for cell differentiation.

Differentiation of adipose tissue-derived mesenchymal stem cells into cardiomyocytes.

BACKGROUND: Cardiomyocytes have small potential for renovation and proliferation in vivo. Consequently, the heart muscle has limited capacity of self-renewal. Mesenchymal stem cells (MSC) therapy, as well as MSC differentiated into cardiomyocytes, has been used in the attempt to minimize the effects of ischemic-hypoxic lesions and those affecting the electrical conduction system of the heart. OBJECTIVE: The present study compared three distinct protocols for induced differentiation of MSC into cardiomyocytes aimed at finding a viable method for producing a large number of functional cells expressing cardiomyogenic phenotype. METHODS: Mesenchymal stem cells were obtained from the adipose tissue of young transgenic Lewis rats expressing green fluorescent protein (GFP), and submitted to three distinct differentiation-inducing media: 1) Planat-Bérnard, 2) 5-azacytidine, and 3) Planat-Bérnard + 5-azacytidine; further, these cells were identified based on the expression of cardiac cell markers. RESULTS: All three protocols detected the expression of sarcomeric-alpha-actinin protein in the exoskeleton of cells, expression of connexin-43 in the nuclear and cytoplasmic membrane, and formation of gap junctions, which are necessary for electrical impulse propagation in the myocardium. However, no spontaneous cell contraction was observed with any of the tested protocols. CONCLUSION: Induction with 5-azacytidine provided an effective cadiomyogenic cellular differentiation similar to that obtained with Planat-Bénard media. Therefore, 5-azacytidine was the method of choice for being the simplest, fastest and lowest-cost protocol for cell differentiation.