Effects Of Exercise On The Expression Of Aromatase And The Activated Of Protein Signaling Pathways In Skeletal Muscle

Objective Age-related muscle wasting(sarcopenia)is accompanied by a decrease in estrogen levels which can compromise the health of aging women.Recent studies have shown that the key enzyme of estrogen synthesis(aromatase cytochrome P-450)is detected in the skeletal muscle.Whether exercise induce the expression of aromatase and estrogen production in the skeletal muscle is unknown,and whether the local synthesis of estrogen can improve the quality of skeletal muscle has not been reported.The purpose of this study was to investigate the effects of exercise on the expression of aromatase and the activated of protein signaling pathways in skeletal muscle.Methods 25 healthy female SD rats(12 weeks,weight 285.27 ± 20.41 g,from the Second Military Medical University Experimental Animal Center)were housed in the Shanghai University of Sport Animal Feed Center to adapting to the local environment for 1 week.Then all of rats were bilateral oophorectomy.After two weeks of adaptation,the rats were randomly divided into 2 groups,treadmill running(n=10)and sedentary(n=10)group.The rats of trained group took part in treadmill training for 8 weeks,6 times every week,25m/min;The control group was fed for 8 weeks.After the last exercise,the bilateral soleus muscle and plantar muscle were harvested.Immunofluorescence assay was used to detect estradiol and aromatase levels and immunofluorescence localization of right soleus muscle and plantar muscle.Detected the expression of AKT,Aromatase,Fox O1/Fox O3,Myo D protein and phosphorylation level by Western blotting.Results 1.There was no significant difference in body weight between treadmill running group and sedentary group(357.42 ± 28.78 g,347.14 ± 31.46g).However,as compared to the control group,a higher weight were observed in the plantar muscle(459.28 ± 32.15 mg,396.78 ± 26.46 mg,p<0.05)and the sole muscle(322.64 ± 20.87 mg,265.33 ± 22.17 mg,p<0.05)after training.2.The immunofluorescence staining results showed that there were a significant increase in Aromatase positive expression in skeletal muscle in the treadmill running group(p<0.05).Western blot analysis showed that the level of aromatase in exercise group was significantly higher than the control group(p<0.01).3.The results of estrogen immunofluorescence staining showed that the expression of estradiol in the sole of the exercise group was significantly higher as compare to the control group(p<0.05).However,there was no significant difference between the exercise group and the control group in the plantar muscle.4.The expression of Myo D and AKT in the exercise group was significantly higher than the control group(p<0.05)in the bilateral soleus muscle and plantar muscle.The expression of Fox O1 / Fox O3 was significantly lower than the control group(p<0.05)in the bilateral soleus muscle and plantar muscle.Conclusions Exercise can improve the quality of skeletal muscle at low estrogen level,and promote the expression of aromatase and estrogen production in skeletal muscle.It suggested that exercise can improve the quality of skeletal muscle,which may promote the production of estrogen and regulate the expression of skeletal muscle protein synthesis.