The Effects Of HIIT And Medium And High Intensity Exerciseon On The AKT/mTOR And AKT/GSK-3 Beta Signaling Pathways In Skeletal Muscle

Research purposes: Exercise contributes to the improvement of all aspects of the body,including maintaining or even increasing skeletal muscle mass.It is well known that resistance exercise can increase protein synthesis and skeletal muscle hypertrophy.It is generally believed that endurance exercise has no effect or increase on skeletal muscle mass,but our previous studies have shown that high-intensity interval training has no effect on skeletal muscle mass.On the contrary,the relative of skeletal muscle mass in medium-high intensity endurance exercise has increased.This study intends to further explore whether there is a difference in the effects of medium-high intensity endurance exercise and high-intensity interval training on skeletal muscle synthesis signaling pathway,in order to provide a theoretical basis for mass exercise design exercise prescription.Subjects and Methods: Eighteen 8-week-old SD rats were randomly divided into three groups: quiet group(group A),moderate intensity continuous training group(group M),high intensity intermittent training group(HIIT)(group H).All rats took natural circadian rhythm activities and ate freely.Group A did not participate in any exercise training;Group M and Group H performed a treadmill exercise in a combination of slope 0,manual drive and tail electrical stimulation.Group M(speed35m/minx40min),group H(speed 40m/minx2min+15m/minx2)x6,6 days of training per week,rest on Sunday,for a total of 12 weeks of training.After 24 hours of training,the rats were weighed in the fasted state,anesthetized by intraperitoneal injection of20% urinary sugar(5 ml/kg),and the extensor digitorum longus and soleus muscles on both sides of the rats were quickly separated and removed,and the wet weight was weighed.The gene and protein expression levels of AKT,mTOR,S6 and GSK-3 beta were detected by fluorescence quantitative PCR and Western blot respectively.All data were processed by SPSS13.0 software and analyzed by one-way ANOVA(significant difference P < 0.05,very significant difference P < 0.01).Results: 1?The expression of AKT mRNA,S6 mRNA and GSK-3 beta mRNA in extensor digitorum longus muscle were significantly increased after 12 weeks of medium and high intensity continuous training and 12 weeks of HIIT(P < 0.05).mTORmRNA did not change significantly.12 weeks of medium and high intensity continuous training and 12 weeks of HIIT had no significant effect on the expression of AKT mRNA,S6 mRNA,mTOR mRNA and GSK-3 beta mRNA in soleus muscle(P > 0.05).2?The S6 and its levels of phosphorylation in extensor digitorum longus muscle increased significantly(P < 0.05),while the levels of AKT,mTOR,GSK-3 beta and phosphorylation tend to increased(P > 0.05),but there were no significantly.12 weeks HIIT had no significant effect on mTOR,GSK-3beta,S6 and phosphorylation in extensor digitorum longus muscle.12 weeks of medium and high intensity continuous training and 12 weeks of HIIT had no significant effect on AKT,mTOR,GSK-3beta,S6 and their phosphorylation.12 weeks HIIT had no significant effect on them.12 weeks of medium and high intensity continuous training and 12 weeks of HIIT had no significant effect on AKT,mTOR,GSK-3beta,S6 and their phosphorylation.3?12-week HIIT increased the expression of AKT in the extensor digitorum longus(P<0.01),but there was no difference change in phosphorylation.12 weeks HIIT extensor digitorum longus muscle S6,mTOR,GSK-3 beta and its phosphorylation were lower than 12 weeks of moderate intensity continuous training,but only the change of S6 was statistically significant.Conclusion:1.12 weeks of medium-high intensity continuous training activated AKT/mTOR signaling pathway in fast muscle,but not in slow muscle.2.12 weeks of high-intensity interval training did not activate AKT/mTOR and AKT/GSK-3 beta pathways in fast and slow muscles.