Effect Of Endurance Exercise On T-cadherin And Its Myocardial Protective Effect In Old Mice

Objective: To explore the effect of endurance exercise on the expression of T-cadherin,its ligand adiponectin and downstream related protein molecules in the myocardium of aged mice,to elucidate the protective mechanism of endurance exercise on aged myocardium and the value of T-cadherin in it.Methods: This experiment is divided into two parts.The first part explores the effect of endurance exercise on the expression of T-cadherin and adiponectin / T-cadherin / AMPK cascade in aged mice.Thirty 17-month-old C57 male elderly mice were randomly divided into an elderly exercise group and an elderly control group,with 15 mice in each group.The mice in the elderly exercise group underwent 12-week moderate-intensity endurance exercise.The elderly control group was reared routinely without exercise intervention.Another 15 2-month-old C57 male mice were included in the young control group,Routine feeding without exercise intervention.Immunohistochemical method was used to observe the distribution and positive expression of T-cadherin and its ligand adiponectin in the myocardial tissues of the elderly exercise group,the elderly control group and the young control group,and to detect the myocardial tissue T-cadherin by immunoblotting,Adiponectin expression and AMPK phosphorylation level.The second part discusses the protective effect of endurance exercise on the myocardium of aged mice.Immunoblotting was used to detect the expression of pro-apoptotic protein molecules Bax and Caspase-9 and inhibitor of apoptosis protein molecule Bcl-2 in three groups of myocardial tissues;And positive expression,immunoblotting to detect the expression of autophagy protein Beclin-1,and to suppress the activation level of autophagy protein mTOR;immunoblotting to detect the expression of fibrosis-related molecules TGF-β1,CollagenⅠ,and CollagenⅢ in each group Scarlet staining was used to observe the degree of myocardial fibrosis in each group.Results: T-cadherin was located in the cell membrane and vascular endothelium of cardiac myocytes,adiponectin was located in the cell membrane,cytoplasm and vascular endothelium of cardiac myocytes;The results of immunohistochemistry and Western blotting showed that the expression of T-cadherin and its ligand adiponectin in the old control group was significantly lower than that in the young control group(P < 0.05),Western blotting showed that the activation level of AMPK in the old control group was significantly lower than that in the young control group(P < 0.05);the old exercise group received 12 weeks of endurance exercise training Compared with the control group,the expression of T-cadherin and adiponectin and the activation level of AMPK increased significantly(P < 0.05).Compared with the young control group,the expression of bcl-2,a pro-apoptotic protein,in the myocardium of the elderly control group was significantly down-regulated,and the expressions of pro-apoptotic proteins bax and Caspase-9 were significantly up-regulated(P <0.05),Compared with the elderly control group,the expression of Bcl-2 was significantly up-regulated,Bax and caspase-9 was significantly down regulated in the elderly exercise group(P < 0.05).Compared with the young control group,the activity of mTOR in the old control group was significantly up-regulated,and the expression of Beclin-1 was significantly down regulated(P < 0.05);compared with the old control group,the activity of mTOR in the old exercise group was significantly down regulated,and the expression of Beclin-1 was significantly up regulated(P < 0.05).Compared with the control group,the expression of TGF-β1,Collagen Ⅰ and CollagenⅢ in the elderly group was significantly increased(P < 0.05),and the degree of myocardial fibrosis was increased.However,after 12 weeks of endurance exercise,the expression of TGF-β1,Collagen Ⅰ and CollagenⅢ in myocardial fibrosis decreased significantly(P < 0.05)and the degree of fibrosis decreased in the elderly exercise group compared with the elderly control group.Conclusion: Endurance exercise can enhance the expression of T-cadherin,promote the combination of adiponectin and myocardial tissue,stimulate the activation of AMPK,and affect the expression of downstream apoptosis,autophagy and fibrosis related signal proteins,so as to achieve the protective effect on the aged myocardium.