METHODS: Eighteen male SD rats were divided into control group, model group and ghrelin group. HE staining was used to observe the morphology of retina, TUNEL staining was used to observe apoptosis, transmission electron microscope was used to observe the ultrastructure of retinal pigment epithelium, immunohistochemistry was used to detect oxidative stress index, and ELISA was used to detect the content of inflammatory factors.

RESULTS:Morphological observation showed that ghrelin could reduce the degree of retinal tissue damage and the apoptosis of retinal tissue in diabetic rats. The results of immunohistochemistry showed that the activities of SOD(superoxide dismutase)and glutathione peroxidase(GSH-Px)in retina tissue of ghrelin group were increased, and the content of malondialdehyde(MDA)was decreased, compared with model group(P<0.05). ELISA results showed that intercellular cell adhesion molecule-1(ICAM-1), tumor necrosis factor-a,(TNF-a)and interleukin-1β(IL-1β)in model group were significantly higher than those in control group(P<0.05). After ghrelin intervention, the expression of inflammatory factors decreased, compared with model group(P<0.05).

CONCLUSION:Ghrelin could effectively retard the progression of diabetic retinopathy in diabetic rats, and its mechanism was related to lowering the level of oxidative stress and inhibiting inflammation.