Effects Of Treadmill,Weight-bearing Ladder Training On MtDNA Deletion And Myocardial Mitochondrial Function In SAMP8 Mice

Study objective:To observe and investigate the effect of aerobic exercise and aging on myocardial mitochondrial DNA(mtDNA) deletion and function.By two different training methods,we study the myocardial mtDNA complex activity and mtDNA deletion of aging mice,and then explore the effect of the two different training methods on anti-aging,thus providing experimental basis for guiding people to exercise scientifically and rationally,and give references to the study of postponing the myocardial sarcopenia.Study methods:According to the age and types of training,36 healthy male SAMP8 mice are divided into 6 groups:3-month-old aerobic exercise group(3ME), 3-month-old resistance exercise group(3MR),3-month-old quiet group(3MC) and 6-month-old aerobic exercise group(6ME),6-month resistance exercise group(6MR) and 6-month-old quiet group(6MC).Each group has 6 mice.3ME and 6ME are made treadmill training for half an hour in the afternoon from Monday to Friday,which will last 8 weeks.While 3MR and 6MR are made weight-bearing ladder training,and they bear 50 percent of their weight in the first week,then gradually increase to 100 percent of their weight,and finally execute them to take out their myocardial tissue to preserve in -80℃after one-day rest.The study uses polymerase chain reaction(PCR) technology to detect defects in mtDNA,UV spectrophotometry to detect the activity of complexⅠand complexⅢ, paleography to detect the activity of complexⅣ,one graphics processing software IPP and one data processing software EXCEL to analyze the results statistically.Results:(1) The activity of complexⅠ:In 3-month-old and 6-month-old mice group,the activity of complexⅠin aerobic exercise groups increases more significantly than in quiet ones,and the group with weight-bearing ladder training increases more significantly than the group with treadmill training.But the activity of complexⅠof the 3-month-old group increases more significantly than the 6-month-old group.(2) The activity of complexⅢ:In 3-month-old and 6-month-old mice group,the activity of complexⅢin aerobic exercise groups increases more significantly than in quiet ones,and in different age groups the rising trend of the complexⅢis quite similar.(3) The activity of complexⅣ:Compared with quite groups,the activity of complexⅣin groups with weight-bearing ladder training increases more significantly than in groups with treadmill training.But the activity of complexⅠof the 6-month-old group increases more significantly than the 3-month-old group.(4) the deletion rate of myocardial mtDNA:In 3-month-old groups,the deletion rate of myocardial mtDNA in aerobic exercise groups increases more significantly than in quiet ones;while in 6-month-old groups,the deletion rate of myocardial mtDNA in aerobic exercise groups decreases more significantly than in quiet ones, and the deletion rate in groups with treadmill training decreases more significantly than in groups with weight-bearing ladder training.Conclusion:(1) The activity of complexⅠ,ⅡandⅣin 6-month-old groups is obviously lower than in 3-month-old groups,and the deletion rate of myocardial mtDNA in 6-month-old groups is obviously higher than in 3-month-old groups.It explains that the age of mice has a positive correlation with the function of mitochondrion,which is the same with previous reports.(2) For 3-month-old mice,we can conclude that two types of exercise make the function ofmitochondrion change to some extent,and their effect is almost the same, which suggests that weight-beating ladder training and treadmill training can restrain the occurrence of myocardial sarcopenia;while for 6-month-old mice,after two types of exercise,the function of mitochondrion changes significantly,which shows that different exercise can protect the function of mitochondrion to different extents, and there are different mechanisms to slow down the deletion rate of myocardial mtDNA in weight-bearing ladder training and treadmill training.