The Effect Of Different Load Exercises On Apoptosis And Bcl-2 Expression In Cardiac Muscle Of Mice

Destination: Through researching on the affection about the programmed cell death and the expression change of the related gene Bcl-2 and the activity change of the myocardium's SOD and the content change of the myocardium's MDA after different load stamina training swimming exercise, in order to found the general regulation about them. Then we can establish rational exercise load and offer theory for the training.Method: Produce middle load training and high load exercise training models.36 male Wistar rats were separated randomly into sedentary control group (group A),middle load exercise group (group B), high load exercise group ( group C),and every group had 12 rats.(1) Group A was bred normal without any exercise;(2) Group B was trained 6 days every week .They were trained 10 minutes on the first day and added 10 minutes every day until the time reached 120 minutes at the second weekend. Keep 120 minutes every day to the eighth weekend. (3) Group C was trained in the same way of the front two weeks compared with group B's. From the third week group C bore a heavy burden on the tail (the rat was born 1% weight of its body in the beginning and the load reached to 5% weight of its body on the third weekend gradually). From the forth week group C was trained 2 times every day, born 1% weight of its body,120 minutes every time. After 8 weeks, exercise training was stopped and all rats were killed the next day. The changes of HE,apoptosis,Bcl-2 expression,SOD activity,MDA content in left ventricular muscle were observed. Then analyze the otherness and the relativity of the indexes of the different load exercises.Result: The left ventricular muscle fibers of group C hypertrophy, and had nothing distinct necrotic cell death. Group B and group C all had apoptotic cells, but we had not found it in group A. Apoptotic index of group C was higher significantly than group B (P<0.01). Every group had Bcl-2 expression. Bcl-2 expression of group B and group C were higher than group A. Group B was higher significantly than group A (P<0.01). Group C was higher than group A (P<0.05) and lower than group B (P<0.05). SOD activity of group C was lower than group A (P<0.05).MDA content of group C was higher than group A and group B (P<0.05). SOD/MDA of group C was lower than group A and group B (P<0.05).Conclusions: Different load swimming trainings results in different changes on both structure and apoptosis. High load exercise does harm to the myocardial cell. Compared with the middle load exercise group, the apoptotic index was increased apparently. The increase of apoptosis cardiac myocyte might be the pathological and physiological mechanism for lowering cardiovascular function after high load exercise. After high load exercise the decrease of Bcl-2 expression of cardiac myocyte maybe one of the mechanism of genetic controls on apoptosis in cardiac muscle cell. Middle load exercise could increase the capacity of antioxidation ,but high load exercise cause the decrease of the capacity of anti-oxidation and the increase of oxygen free radicals, which might also be one of the mechanisms for regulating the apoptosis of cardiac muscle cell.