[Salidroside alleviates retinopathy in diabetes rats by inhibiting oxidative stress and immune inflammation through activating PI3K/AKT pathway].

Objective To investigate the ameliorative effect of salidroside on diabetes retinopathy (DR) rats and its mechanism. Methods Male SD rats were randomly divided into blank group, model group, low-dose and high-dose salidroside treatment groups. Except for the blank group, other groups were modeled by intraperitoneal injection of streptozotocin. After successful modeling, treatment groups were injected intraperitoneally with [50 mg/(kg.d)] and [100 mg/(kg.d)] salidroside respectively, for 4 weeks; the blank group and model group were injected with corresponding doses of saline. ELISA was used to measure the expression levels of antioxidant-related enzyme activity and inflammatory factors in blood glucose and serum of rats in each group. Retinal tissue lesions were detected by HE staining, and the expression of vascular endothelial growth factor (VEGF) and intercellular adhesion molecule 1 (ICAM-1) in retinal tissues were detected by immunohistochemical staining. Western blot analysis was used to detect the expression of phosphatidylinositol 3 kinase (PI3K) , nuclear factor κB p65 (NF-κB p65), phosphorylated p38 MAPK (p-p38 MAPK), and phosphorylated protein kinase B (p-AKT) proteins. Results Compared with model group, salidroside could significantly reduce blood glucose level and increase body mass in DR rats. The serum levels of superoxide dismutase (SOD) and catalase (CAT) were significantly increased, while the levels of malondialdehyde (MDA), tumor necrosis factor α (TNF-α), interleukin 6 (IL-6) and IL-1β were reduced. The protein expression of VEGF, ICAM-1, NF-κB p65 and p-p38 MAPK was significantly decreased, while the protein expression of PI3K and p-AKT was increased. Conclusion Salidroside can reduce DR in rats by inhibiting oxidative stress and immune inflammatory response, which may be related to the reduction of abnormal expression of VEGF and ICAM-1 and the activation of PI3K/AKT signaling pathway.