Effects Of HIIT And Moderate-intensity Aerobic Exercise On Skeletal Muscle Mass In Young Rats

Objective:After 4 weeks of HIIT and moderate-intensity aerobic exercise intervention in young rats,observe the changes in skeletal muscle mass and the expression of key proteins in AMPK/PGC-1α and plays a role in it.Method:Select 40 male SD rats aged 4 weeks and randomly divide them into high-intensity intermittent exercise group A(high and low intensity respectively 1 80%vVO2max,15%vVO2max,time 1:2)and B(high and low intensity respectively 140%vVO2max,35%vVO2max,time 1:2),moderate-intensity aerobic exercise group C(intensity of 90%vVO2max)and D(intensity of 70%vVO2max)and quiet group E,before and after training,the mice were weighed,DEXA measured body composition,using HE staining method to calculate the cross-sectional area of muscle fibers,and Western Blot was used to detect the protein expression of AMPK,PGC-1α,PI3K,and AKT related to protein synthesis in skeletal muscleResults:(1)After 4 weeks of exercise intervention,compared with the control group E,the weight of the rats in the HIIT group and the moderate-intensity aerobic exercise group was significantly reduced(P<0.05),and the muscle mass was significantly increased(P<0.05);Compared with the moderate-intensity aerobic exercise group,the muscle mass of the higher-intensity HIIT group increased significantly(P<0.05),while the lower-intensity HIIT group had no significant difference.(2)Compared with the control group E,the cross-sectional area of soleus and gastrocnemius muscle fibers in the HIIT group and the moderate-intensity aerobic exercise group were significantly increased(P<0.05);compared with the lower-intensity moderate-intensity aerobic exercise group,the cross-sectional area of soleus and gastrocnemius muscle fibers in the HIIT group was significantly increased(P<0.05).(3)Compared with the control group E,the gastrocnemius muscle PGC-1α protein expression levels in the lower-intensity HIIT group and the higher-intensity moderate-intensity aerobic exercise group increased significantly(P<0.05),and the protein expression levels of AMPK,PGC-1α and PI3K in the soleus muscle of the higher-intensity moderate-intensity were significantly increased(P<0.05),and the protein expression of AMPK,PGC-1α,PI3K and AKT in the soleus and gastrocnemius muscles in the higher-intensity HIIT group and the lower-intensity moderate-intensity aerobic exercise group was no significant difference.Conclusion:(1)Both HIIT for 4 weeks and moderate-intensity aerobic exercise could promote the increase of skeletal muscle mass,and HIIT was better in terms of effect.(2)4 weeks of HIIT increased the expression level of key proteins on the AMPK/PGC-1α pathway,but did not increase the expression level of key proteins on the PI3K/AKT pathway;4 weeks of moderate-intensity aerobic exercise increased AMPK/PGC-1α and PI3K/AKT expression levels of key proteins in the two pathways.