Effect Of Aerobic Exercise On Autophagy Of Myocardial Cells In Rats With Myocardial Infarction

ObjectTo investigate whether different length of aerobic exercise has an effect on myocardial autophagy in myocardial infarction(MI)rats,and to improve cardiac function.MethodsForty male 8-week-old SD rats were randomly divided into sham operation group(Sham),myocardial infarction(MI),MI plus exercise with 8 weeks(ME),10 rats/group.MI model was constructed by anterior descending coronary artery(LAD)ligation surgery.Exercise training of ME group had been began one week after MI.Exercise program:after one week of adaptive motion,10 m/min warm-up with 10 min per day,then at 20 m/min sports with 8min,then at 15 m/min sports with 2 min.There were 4 cycles alternating.The last 20 m/min sports 8min,10 m/min 2 min at the end of the exercise.It was training once a day,5 d/w,group ME trained 8w.The structure and number of autophagosome were observed by electron microscopy.The expression of ATG5,Beclinl,LC3-I and LC3-?in autophagy related genes were detected by RT-PCR.mRNA expression levels and the protein expression levels of autophagy related genes LC3 and Belcinl were detected by ELISA.Results(1)MI surgery could attenuate the ventricular wall and reduce ejection function(EF)obviously;aerobic exercise thicken the RVWT and enhance the eject function of the MI mice.Among them,the sum of the thickness in diastolic ventricle septa and in diastolic left posterior wall of ME group is higher than that of MI group obviously(P<0.05).(2)The myocardium of MI group and ME group were significantly damaged,the structure of myocardial cell was incomplete,the fiber interruption was obvious and the autophagosome was almost invisible.ME group had obvious improvement,and the continuous degree of myofibers was improved in single field of vision The presence of multiple autophagosomes can be seen.(3)The results of ELISA of Beclinl and LC3 showed that Beclinl in plasma of ME group were significantly higher than MI group(P<0.05),myocardial tissue was significantly higher than MI group(P<0.01),LC3 in plasma and Myocardial tissue than the MI group were significantly increased(P<0.01);(4)The levels of ATG5,Beclinl,LC3-I,LC3-II mRNA expression in the ME groups were significantly higher than those in the MI group(P<0.01).Aerobic exercise increased the ratio of LC3-?/LC3-??Conclusions(1)Aerobic exercise is beneficial to the improvement of myocardial systolic and diastolic function in MI rats.(2)Aerobic exercise may enhance and improve cardiac function of MI rats by regulating the expression of myocardial autophagy related genes in MI rats.