Efeitos do exercício físico sobre as propriedades morfológicas e mecânicas de miócitos cardíacos de ratos diabéticos

• Ano de defesa: 2010
• Autor(a) principal: Silva, Márcia Ferreira da
• Orientador(a): Natali, Antônio José
• Banca de defesa: Lima, Nilo Resende Viana , Carlo, Ricardo Junqueira Del
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Educação Física
• Departamento: Aspectos sócio-culturais do movimento humano; Aspectos biodinâmicos do movimento humano
• País: BR
• Palavras-chave em Português: Cardiomiopatia diabética; Cardiomiócitos; Exercício físico
• Palavras-chave em Inglês: Diabetic cardiomyopathy; Cardiac myocytes; Exercises
• Área do conhecimento CNPq: CNPQ::CIENCIAS DA SAUDE
• Link de acesso: http://locus.ufv.br/handle/123456789/3459

The aim of this study was to verify the effects of a swimming training (ST) on the morphological and mechanical properties of cardiac myocytes from different regions of the left ventricle (LV) of rats with experimental diabetes. One month old male Wistar rats (body mass ~ 250g) received an intraperitoneal injection of Streptozootocin (STZ, 60mg/kg body mass) diluted in 1 mL sodium citrate buffer (0, 1 M, pH 4.5) or the same dose of sodium citrate buffer (0, 1 M, pH 4.5). Those rats with blood glucose levels above 300 mg/dL were randomly divided into diabetic sedentary (DS, n=20) and diabetics exercised (DE, n=20). Age and body mass-matched animals served as control non diabetic (CN, n=10) and control non diabetic exercised (CNE, n=10). Animals from DE and CNE groups were submitted to a swimming program (SP) (5 days/week, 90 min/day), for 8 weeks. At sacrifice the heart was removed and myocytes from sub-epicardium (EPI) and sub-endocardium (ENDO) regions of the LV were isolated and stimulated at 1 and 3 Hz, at room temperature (~25ºC). Experimental diabetes reduced animals' body mass, relative LV mass and tibia length. The SP did not affect body mass and blood glucose levels, but increased the relative LV mass of diabetic and non diabetic animals. No regional differences (EPI vs ENDO) between morphological and mechanical properties were found in response to either diabetes or SP. However, diabetes reduced cell length, width, volume and amplitude of contraction, and prolonged the time course of cell contraction and relaxation. The SP increased cell width and volume of cardiac myocytes of diabetic rats without changing cell length. I addition increased the amplitude of contraction and reduced the time course of cell contraction and relaxation. It was concluded that the SP affected the morphological properties of LV myocytes from rats with experimental diabetes and attenuated the mechanical dysfunctions of this cells with no regional distinction.