Effects Of Endurance, Resistance And Mix Training On The Apoptosis Mediated By TNF-α In Cardiac Myocyte Of C57BL/6 Mice

As one of the world's three major diseases, cardiovascular disease is seriously affecting human health, especially the elderly people. Delaying aging and improving life of the elderly people are becoming hot spots in medical, biological and even the field of sports science in the future. By contrast with drug prevention and treatment, physical activity is undoubtedly cheaper and more enjoyable. Appropriate exercise improves cardiac hypertrophy, which is different from pathological cardiac hypertrophy in morphology and function. This provides a theoretical basis on improving the number and function of the cardiac myocyte through exercise.In traditional thoughts, apoptosis doesn't exist in the mature cells which doesn't have regenerative capacity, such as cardiac myocyte and nerve cells. However, in late 1980's, studies had shown that apoptosis also exists in cardiac myocyte. Cardiac apoptosis plays an important role in the pathophysiology of heart development, ischemia-reperfusion injury, spontaneous hypertension, arrhythmia, heart failure, cardiac muscle sarcopenia and many other heart-related diseases. And cardiac apoptosis have been considered as the cellular basis in the change from compensatory to pathological.TNF-αis a pleiotropic pro-inflammatory cytokines and plays an important role in inflammation, immune response regulation, cell proliferation/differentiation and anti-viral response. Recent years, the studies of TNF-αpaid more attention in inflammation and immunological aspects, while there were very few studies about the effects of exercise on the apoptosis pathway which mediated by TNF-αin cardiac myocyte.Objective:One aim of this study is to investigate the effects of 28-week endurance, resistance and mixed training on the expression of the signal molecules Caspase-8,Caspase-3 and NF-κBmRNA in the apoptosis pathway which mediated by TNF-a in the cardiac myocyte of C57BL/6 mice. The other is to observe the effects of 3 different of forms of trainging on cardiac myocyte in morphology.Methods:32 male C57BL/6 mice were randomly assigned to endurance training group(E, n=8), resistance training group(R, n=8), mixed-training group(M, n=8) and control group (C, n=8). All the training groups were trained on Monday, Wednesday, Friday and Sunday per week and last for 28 weeks. Endurance training group mice were accustomed to treadmill training with no weight bearing, and with a speed from 0.8km/h to 1.2km/h gradually for 30min; resistance training group mice were engaged climbing training by weighted at the end of tails from 10% of its own weight to 150% gradually and then to 120% in the last 4 weeks; mixed-training group mice were to engaged climbing training on Monday, Friday, and engaged endurance training on Wednesday and Sunday.Results:(1)The body weight of mice were significantly increased after 28 weeks and the heart index of training groups were higher than the control group.(2)3 different forms of training reduced TNF-αmRNA expression in cardiac myocyte of C57BL/6 mice. Endurance training group had very significant difference with the control group(P<0.01), while resistance training group and mix training group also had significant difference(P<0.05).(3)3 different forms of training reduced Caspase-8mRNA expression in cardiac myocyte of C57BL/6 mice. Endurance and resistance training group both had very significant differences with the control group(P<0.01), while mix training group didn't(P>0.05).(4)3 different forms of training reduced Caspase-3mRNA expression in cardiac myocyte of C57BL/6 mice. Endurance training group had a significant difference with the control group(P<0.05), while resistance and mix training group didn't(P>0.05).(5)Endurance and mix training increased NF-KBmRNA expression in cardiac myocyte of C57BL/6 mice with significant difference(P<0.05), while the resistance training group had no significant change(P>0.05).Conclusion:(1)3 different forms of training have effect on the body weight of C57BL/6 mice.The reason why the body weight of control group mice increased significantly may probably due to an increase in the body fat. The body weight of endurance training group mice were the lowest among groups, meant that the mechanism of weight control by endurance training may have relation with the effective regulation of lipid metabolism. (2)3 different forms of trainings increased the heart index of C57BL/6 mice. It can be considered that appropriate training improves cardiac hypertrophy.(3)Endurance training reduced TNF-α, Caspase-8, Caspase-3mRNA expression in cardiac myocyte of C57BL/6 mice significantly, while increased NF-KBmRNA expression significantly among 3 traing groups. It is indicated that endurance training is effective in stimulating cardiac hypertrophy, inhibiting cardiac apoptosis and delaying myocardial aging.(4)The effects of resistance and mix training on the signal molecules in the apoptosis pathway which mediated by TNF-αin the cardiac myocyte were not all significant. It is indicated that the 2 forms of training didn't have the same effect on inhibiting cardiac apoptosis and delaying myocardial aging.