Alterations of Sirt1 and mTOR activity in gastrocnemius muscle of mice with sarcopenia / 基础医学与临床

ABSTRACT

Objective To observe the alterations of Sirt1 and mTOR activity in gastrocnemius muscles of mice with sarcopenia. Methods Aged (26 months old) and young (6 months old) male C57BL/6J mice (n=16,respective-ly) were randomly arranged into 2 groups respectively, i. e. middle-aged control ( MC) , middle-aged suspension ( MS) , aged control( AC) and aged suspension( AS) . Aged mice were hindlimb suspended for two weeks to estab-lish a sarcopenic model. Kits and Western blot were used to detecte related factors and protein expression of Sirt1 and mTOR pathway. Results 1) the content of NAD+and the ratio of NAD+/NADH AC group was significantly lower than MC group ( P＜0.01 or P＜0.05) , HLS group was significantly less than the control group ( P＜0.01 or P＜0.05) . 2) Sirt1 expression AC group was significantly higher than MC group ( P＜0.05) , and HLS group was significantly higher than that of the control group (P＜0.05).3)Sirt1 downstream substrates (PGC-1α, FOXO1 and P53), NAMPT protein expression and Sirt1 activity AC group was significantly lower than MC group ( P＜0.05 or P＜0.05 or P＜0.01) , HLS group was significantly less than the control group ( P＜0.05 or P＜0.05 or P＜0.05) . 4) phosphorylation of mTOR, p70S6K and 4E-BP1 AC group was significantly higher than MC group ( P＜0.05) , HLS group was significantly less than the control group ( P＜0.05) . Conclusions Sirt1 and mTOR are involved in the pathogenesis of mice with sarcopenia.