AIM:To observe the protective effect of Danhong injection on retina of diabetic rats and explore its mechanism.

METHODS: From June 2015 to December 2016, sixty male SD rats were randomly divided into four groups: normal group, diabetic group, Danhong intervention group and blank intervention group. The rats in the latter three groups were injected with 50 mg/kg of streptozotocin(STZ)into the abdominal cavity to establish diabetic retinopathy rat model. On the day after successful modeling, Danhong treatment group was injected with 5 ml/kg Danhong injection intraperitoneally every day, while the blank intervention group was treated with intraperitoneal injection of distilled water with the same volume as Danhong treatment group. Therapeutic effects were observed from two levels: retinal vascular disease and nerve injury. Retinal morphology was observed by hematoxylin-eosin(HE)staining at the level of vascular disease. The expression of retinal vascular endothelial growth factor(VEGF)was detected by immunohistochemistry. Neurological injury level: tunel staining was used to observe apoptotic cells, and transmission electron microscopy was used to observe the morphology of retinal ganglion cells.

RESULTS:Vascular level: in the normal group, the structure of retinal tissues showed clear layers. The structure of the diabetic group and blank intervention group was more disordered than that of the normal group, and the Danhong treatment group was better than that of the diabetic group and blank intervention group. Compared with the diabetic group and blank intervention group, the expression of VEGF in Danhong intervention group decreased. Neurological injury level: there was a larger degree of apoptosis of ganglion cells in the diabetic group and the blank intervention group, while the number of apoptotic cells in the Danhong intervention group was lower than the diabetic group and blank intervention group.

CONCLUSION:Danhong injection has protective effect on the retina of diabetic rats. It can improve the condition of retinal ischemia and hypoxia by down-regulating VEGF, reduce the formation of retinal neovascularization. At the same time, it can reduce the apoptosis of retinal nerve cells to acertain extent.