The Effect of Accumulated Exercise on Myocardial Collagen Fibers in Insulin Resistant Mice

Accumulated exercise is an effective means for breaking sedentary behavior and improving metabolic health. To explore the health intervention value of accumulated exercise, the effects of different intensities of accumulated exercise and continuous exercise have been compared on insulin resistance (IR) status, myocardial collagen fibers, and myocardial fibrosis protein expression in mice through long-term exercise. The IR mouse model was induced by feeding 112 C57BL/6J male mice (4 weeks old) with high-fat diet. The IR model mice were intervened with moderate intensity continuous exercise, moderate intensity accumulated exercise and high intensity accumulated exercise for 8 weeks. Oral glucose tolerance test(OGTT) was performed, and the mice were sacrificed after blood was collected from the orbit to extract heart tissue. The ELISA method was used to detect serum Fasting insulin(FINS) level, myocardial tissue collagen Ⅰ(COLⅠ), collagen Ⅲ(COLⅢ) and α-smooth muscle actin (α-SMA) content. The Western blot method was used to detect mouse myocardial tissue transforming growth factor-β1(TGF-β1), Smad3 and connective tissue growth factor(CTGF) protein expression level. The results showed that all three kinds of exercise could improve the IR state and myocardial fibrosis degree of IR mice, the effects of high intensity accumulated exercise and moderate intensity continuous exercise were equivalent, while the effect of mode-rate intensity accumulated exercise was weaker.