The Expression and Significance of mTORC1 in Diabetic Retinopathy
Abstract Background: To investigate the expression and significance of mechanistic target of rapamycin complex 1(mTORC1) in diabetic retinopathy(DR), and to find new targets and new methods for the treatment of DR.Methods: A DR rat model was prepared by general feeding combined with intraperitoneal injection of 10% streptozotocin (60 mg/kg). The rats were randomly divided into a control group (NDM group) and diabetes group (DM group).Three months later,the degrees of retinopathy were determined using hematoxylin and eosin staining,and the levels of p-S6, VEGF, and PEDF proteins were detected by immunohistochemistry and western blotting. Human retinal capillary endothelial cells (HRCECs) were cultured in high glucose conditions,then treated with rapamycin or transfected with siTSC1.The protein levels of p-S6 were assessed by western blotting. The 5-ethynyl-2´-deoxyuridine assay was used to detect cell proliferation, and the Transwell assay was used to detect cell migration.Results: A DM rat model was successfully developed. The expressions of p-S6 and VEGF proteins were significantly increased in the DM group (p < 0.05), and the expression of PEDF protein was significantly decreased compared with the control group (p < 0.05). In vitro,the p-S6 protein in high glucose(HG) induced HRCECs was increased compared with the normal control (p < 0.05), and cell proliferation and migration were increased compared with the normal glucose(NG) group (p < 0.05). After transfection with siTSC1 to activate mTORC1,the expression of p-S6 was increased,as well as cell proliferation and migration.In contrast rapamycin decreased p-S6 expression in HG induced HRCECs, as well as decrased proliferation and migration (p < 0.05).Conclusion: The mTORC1 played an important role in DR. After activation, mTORC1 induced expression of the p-S6 protein, regulated the expressions of VEGF and PEDF proteins, and changed the proliferation and migration of endothelial cells.The mTORC1 can therefore be used as a new target,as well as in the treatment of DR.