The Effect Of Endurance Exercise On AKT/mTOR Signaling Pathway Of Skeletal Mass Muscle In The Young And In The Old

Purposes: This study was designed to investigate The effect and mechanism of endurance exercise on the of skeletal mass muscle in the young and the old rats.Method: 12 SPF-grade SD healthy male rats aged 8 weeks were purchased from the Experimental Animal Center of Guangdong Province with a certificate number of SCXK(Yue)2013-0010(average weight of 150 g).12 male SPF-grade SD healthy male rats aged 22 months were purchased from Dashuo Experimental Animal Center of Chengdu with a certificate number of 5000336072(average weight was 778 grams).The specific groups were: youth sedentary group(Y),youth exercise group(YE),elderly sedentary group(O)and elderly exercise group(OE).Exercise groups were trained for five days,followed by 12 weeks of regular exercise training in strict accordance with the exercise program.Twenty-four hours after the final training,the rats were received the 20% ethl carbamate solution(5 ml/kg),afterwards the bilateral soleus muscles(SOL)and extensor digitorum longs(EDL)were recorded and weighed.Hematoxylin and eosin(HE)staining was used to observe the cell morphology and mean cell area.AKT/mTOR/S6 gene expression and protein changes were observed by real-time PCR and Western Blotting respectively.Results: 1 Compared with young rats,the relative quality of EDL and SOL of aged rats was decreased.Compared with the rats in the sedentary group,the relative mass of the EDL increased in the exercise group,and the youth exercise group increased more.2.Compared with the quiet group,the average cell area of the EDL and SOL in the exercise group increased,and the increase in the youth exercise group was more obvious 3.Compared with the young rats,the expression of mTOR mRNA in the SOL of aged rats decreased,the protein content of mTOR and S6 decreased,but the expression of S6 mRNA increased,and the ratio of P-mTOR/mTOR and P-S6/S6 increased.Compared with the youth quiet group,the protein content of AKT in the SOL of the youth exercise group increased.Compared with the old age group,the ratio of P-mTOR/mTOR decreased in the SOL of the old exercise group.4.Compared with the young rats,the expression of mTOR and S6 mRNA in the EDL of aged rats was decreased,and the content of mTOR protein was decreased.However,the ratio of P-mTOR/mTOR in the EDL of the toes increased in aged rats.Compared with the young group,the expression of AKT and S6 mRNA in the EDL muscle increased and the ratio of P-S6/S6 increased in the youth exercise group.Conclusions: 1.Exercise can increase skeletal muscle mass,young rats increase significantly,and older rats increase slowly.2.Senescence inhibits the mTOR signaling pathway,but increase the activity of mTOR in resting state.3.Exercise activates the S6 signaling pathway in young rats,improve the activity of p-S6/S6.