AIM:To investigate the effect of paeoniflorin on the inflammatory response of diabetic retinopathy rats by regulating phosphatidylinositol-3 kinase/protein kinase B(PI3K/Akt)signaling pathway.

METHODS: A total of 70 SPF male SD rats were selected, and 12 rats were randomly selected as the control group(normal saline gavage). The remaining 58 rats were fed with high-sugar and high-fat diet combined with intraperitoneal injection of streptozotocin(STZ)to establish diabetic rat models. Rats with diabetic retinopathy were randomly divided into model group(normal saline), paeoniflorin low-dose group(100 mg/kg paeoniflorin), paeoniflorin high-dose group(200 mg/kg paeoniflorin)and metformin group(100 mg/kg metformin), with 12 rats in each group. The body mass of the rats in each group were compared. HE staining was used to observe the pathological changes of the rat retina. Automatic biochemical analyzer was used to detect the levels of fasting blood glucose, glycosylated hemoglobin, serum high-density lipoprotein cholesterol(HDL-C), low-density lipoprotein cholesterol(LDL-C), total cholesterol and triglyceride in the rats. Enzyme-linked immunosorbent assay was used to detect the levels of serum superoxide dismutase(SOD), reactive oxygen species(ROS), malondialdehyde(MDA), glutathione peroxidase(GSH-PX), tumor necrosis factor-α(TNF-α), interleukin-6(IL-6)and interleukin-1β(IL-1β)in the rats. Western blot was used to detect the expressions of Occludin, p-PI3K, tight junction protein-1(ZO-1), p-Akt and VE-Cadherin in the rat retina.

RESULTS: The expression levels of Occludin, ZO-1 and VE-cadherin in low-dose and high-dose paeoniflora groups were higher than those in the model group, while the expression levels of TNF-α, IL-6, IL-1β, p-PI3K and p-Akt in serum were lower than those in the model group. The high-dose group of paeoniflorin was significantly better than the low-dose group of paeoniflorin(all P<0.05).

CONCLUSION: Paeoniflorin may reduce inflammatory response in diabetic retinopathy rats by inhibiting PI3K/Akt signaling pathway.