Effects Of 16 Weeks HIIT Training On MG29 Protein In Skeletal Muscle And VO2max Of Rats

Objective:To investigate the effctiveness of 16 weeks HIIT on rats aging 29-45 weeks,and then to observe the change of MG29 which closely related with Excitation Contraction Coupling,and the weight,and VO2 max,and the time when exhausted,so as to figure out the agerelated changes of skeletal muscle and CRF(Cardiorespiratory Fitness).In addition,by conducting 16-weeks HIIT(High Intensity Interval Training)intervention to observe its effect on improving skeletal muscle function and CRF.The aim of this study is to provide theoretical basis for the application of HIIT in the prevention of Sarcopenia and the improvement of CRF.Methods: 56 28-week-old male SPF Wistar rats were randomly distributed into basic group(B,n=6),Control group(group C,n=24)and HIIT group(group H,n=26),after 1-week adaptive feeding,VO2 max was measured for the first time,then rats of group B were killed to draw materials,rats of group C stayed sedentary until at 8th and 16 th week were killed to draw materials,and rats of group H were conducted HIIT intervention according the result of first VO2 max test,which consists of high intensity(90%VO2max)and low intensity(50%VO2max)alternatively.After that we repeated the VO2 max test every two weeks on a no-training day and the load of the next two weeks was adjusted according the test result.The HIIT intervention was last for 16 weeks(5d/w,50min/d).The test included the expression of MG29 mRNA by RT-PCR and protein MG29 of rectus femoris by Western-Blot.Results:1)The expression of MG29 mRNA of group H were significantly higher than group C(P<0.05)at 16 th week,but the expression of MG29 in Group H were significantly higher than those in group C(P<0.05)both at 8th and 16 th week.2)The body weight of group C rats increased significantly by 16% at 16 th week(P<0.01),while the body weight of group H rats had no significant change.In contrary,VO2 max of group C significantly decreased by 42.8%(P<0.01)compared with the initial value decreased,but group H only decreased by 25.9%(P<0.01).3)The time of exercise until to be exhausted of group H was higher than group C at both 8th and 16 th week(P<0.05).Conclusions: 1)The process of aging will result in the decline of CRF,but increase of body weight,and 4-weeks of HIIT can significantly inhabit the increase body weight,but at least 16-weeks of HIIT can significantly improve the CRF.2)16 weeks of HIIT can significantly promote the expression of MG29 mRNA,and both 8 and 16 weeks of HIIT intervention can significantly promote the expression of MG29 protein in skeletal muscle.3)both 8 and 16 weeks HIIT can prolong the time The time of exercise until to be exhausted.