Ameliorating effects of sericin on retinal oxidative stress and micro-inflammatory status in diabetic rats / 眼科新进展

ABSTRACT

Objective To investigate the improvement effects of sericin on the retinal oxidative stress and micro-inflammatory state in diabetic rats.Methods A diabetic rat model was established by using high-fat and high-sugar diet and intraperitoneal injection of streptozotocin.Then 24 diabetic rats were randomly divided into sericin treatment group and diabetic model group,with 12 rats for each group,and additional 12 normal rats with the same age were collected as a normal control group.Next,the rats in the sericin treatment group received sericin solution,while the other two groups was given the same amount of normal saline once a day for 35 days.After the agent intervention,the content of malondialdehyde (MDA) and glutathione (GSH) in the retina of all rats were detected by related kits.The expressions of nuclear factor erythroid 2-related factor 2 (Nrf2),heme oxygenase 1 (HO-1),nuclear factor-κB (NF-κB) and tumor necrosis factor-α (TNF-α) protein were detected by Western blot,and finally,the retinal morphology was examined by hematoxylin-eosin staining in the 3 groups.Results The content of MDA,NF-κB and TNF-α protein expression in the sericin treatment group was (4.145 ±0.282) mmol· gprot-1,0.232 ±0.027 and 0.761 ±0.058,respectively,which was significantly lower than that in the diabetic model group [(6.813 ± 0.446) mmol · gprot-1,0.334 ± 0.024 and 0.994 ± 0.084] (all P ＜ 0.05).The content of GSH,Nrf2 and HO-1 protein expression in rat retina in the sericin treatment group was (78.518 ± 4.317) mg · gprot 1,0.591 ± 0.054 and 0.954 ± 0.091,respectively,which was significantly higher than that in the diabetic model group [(59.890 ± 5.932) mg · gprot-1,0.351 ± 0.044 and 0.585 ± 0.054] (all P ＜ 0.05).The diabetic model group presented the disorder arrangement of the neurocyte in different levels in the retina,irregular and swollen inner limiting membrane,vacuoles in the ganglion cells,but in the sericin treatment group,the morphology of retinal layers was more regular and mildly disorderly arranged.The pathological damages in the retina were alleviated significantly.Conclusion Sericin can ameliorate oxidative stress and inflammation in diabetic retina,thereby delaying the development of diabetic retinopathy.