Mechanical Stretch Regulates Glycometabolism Through Estrogen In Mouse C₂C₁₂ Myoblasts

Objective:With aging,women will have some health problems including decreased estrogen,bone mass loss,abnormal glucose and lipid metabolism and so on.In recent years,it has been reported that exercise alleviated type 2 diabetes mellitus effectively of menopausal female,while there are some controversies in the mechanism.As we konw,estrogen plays an important role in the process of mitochondrial function,glycogenesis in liver and glucose homeostasis in adipose tissue.And it has been demonstrated that estrogen supplement improved insulin resistance and increased insulin sensitivity,wheres,the effect of regional estrogen in muscle on glycometabolism remains to be explored.Until now,the effect of exercise-induced estrogen on muscular glycometabolism is not well defined,the current study was designed to explore the effect of mechanical stretch-induced estrogen on glycometabolism in mouse C₂C₁₂2 myoblasts.Methods:The mouse C₂C₁₂2 myoblasts in vitro were plated at BioFlex Culture Plate,and assigned randomly to the control group?C?,stretch group?S?,SA group.S,SA groups were stretched by Flexcell FX-5000^TMM system?magnitude 15%,frequency 1Hz,duration 6hours?.SA group was cultured in growth medium?GM?with 400?g/ml anastrozole?aromatase inhibitor?,and other groups were cultured in GM with DMSO for 36h.Assays were used to detect glucose uptake,estradiol concentration,PFK-1activity and oxygen consumption rate.We detected the protein expression of HK,PI3K,the ratio of p-AKT and AKT,GLUT4 in total protein and membrane protein by western blotting.Results:1.Compared with the control group,estradiol concentration,oxygen consumption rate increased in the stretch group?P<0.05,P<0.05?,and aromatase inhibitor anastrozole addition significantly reduced the estradiol concentration and oxygen consumption rate?P<0.05,P<0.05?.2.Compared with the control group,there was no significant difference in glucose uptake of stretch group?P>0.05?,while glucose uptake decreased in SA group?P<0.05?.3.Compared with the control group,PFK-1 activity and the protein expression of HK elevated in stretch group?P<0.05,P<0.05?,and they reduced in SA group?P<0.05,P<0.05?.4.PI3K,the ratio of p-AKT and AKT,the ratio of GLUT4 in membrane and GLUT4in total protein were higher in stretch group than the control group?P<0.05,P<0.05,P<0.05?.For the SA group,the ratio of p-AKT and AKT,the ratio of GLUT4 in membrane and GLUT4 in total protein were lower than the stretch group?P<0.05,P<0.05?.5.The concentration of estradiol was positively correlated with glucose uptake?P<0.01,r=0.818?.Conclusions:1.Mechanical stretch increases estradiol concentration and oxygen consumption rate of mouse C₂C₁₂2 myoblasts,it improves glycometabolism through elevating HK and PFK1 activity and protein expression of PI3K-AKT-GLUT4 pathway.2.Estrogen mediates oxygen consumption rate,and regulated glucose uptake.It may be related to PI3K-AKT-GLUT4 signaling pathway and activity of glucose metabolic enzymes..