Morphology and contractility in cardiomyocytes of rats with low exercise performance

• Autor(a) principal: Quintão Júnior, Judson Fonseca
• Data de Publicação: 2012
• Outros Autores: Natali, Antônio José, Carneiro Júnior, Miguel Araújo, Castro, Cynthia Aparecida de, Drummond, Lucas Rios, Lavorato, Victor Neiva, Felix, Leonardo Bonato, Cruz, Jader dos Santos, Prímola-Gomes, Thales Nicolau
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://dx.doi.org/10.1590/S0066-782X2012005000036; http://www.locus.ufv.br/handle/123456789/12489
• topic: Myocytes; Cardiac; Rats; Exercise; Fatigue; Myocardial contraction; Physical conditioning animal

Aerobic capacity is essential to physical performance, and low aerobic capacity is related to the triggering of various cardiovascular diseases. To compare the morphology and contractility of isolated rat cardiomyocytes with low performance and standard performance for exercise. Wistar rats with 10 weeks of age underwent a protocol of treadmill running to fatigue, and were divided into two groups: Low Performance (LP) and Standard Performance (SP). Then, the animals were sacrificed, the heart was quickly removed and, by means of enzymatic dissociation, left ventricular cardiomyocytes were isolated. The cell and sarcomeres length and width of cardiomyocytes were measured using an edge detection system. The isolated cardiomyocytes were electrically stimulated at 1 and 3 Hz and cell contraction was measured by registering the change of their length. The cell length was shorter in the LP group (157.2 1.3µm; p < 0.05) compared to SP (161.4 1.3µm), and the same result was observed for the volume of cardiomyocytes (LP, 25.5 0.4. vs. SP, 26.8 ± 0.4 pL; p < 0.05). The time to peak contraction (LP, 116 1 vs. SP 111 2ms) and total relaxation (LP, 143 3 vs. SP 232 3ms) were higher in the LP group. We conclude that left ventricular myocytes of animals with low performance for exercise are smaller than animals with standard performance. In addition to that, they present losses in contractile capacity.