Olive Leaf Extract Protect Diabetic Retinopathy in Diabetic Rats: Antioxidant and Advance Glycation End Products Pathway‎

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Diabetic retinopathy (DR), a major microvascular complication of diabetes mellitus (DM). Long-term hyperglycemia-induced irreversible damage in the retina, leading to DR. Olive leaf extract (OLE) has several health benefits. This research aimed to assess the protective effect of OLE against DR on streptozotocin (STZ)-induced DM in rats with underline antioxidant and protein glycation mechanisms. Diabetes induced in rats via injection with STZ intraperitoneal (i.p.). OLE (200 and 400 mg/kg/day) was given orally for 6 weeks and compared with Metformin (MT), as a reference drug. Change in body weight (BW), serum glucose and lipid profile levels were determined. Antioxidant status and advanced glycation end products (AGEs) biomarkers in retina tissue were measured. The changes in retina tissue in the different groups were examined under the microscope. Significant decrease in BW and increases in glucose, lipids, retina oxidative stress and AGEs levels compared with the control group. Administration of OLE (400 mg/kg) and MT reversed these parameters significantly compared with DM rats. In histology retina tissue showing focal abnormal vascularization of the ganglion layer with vacuolated cells with congested blood capillaries in different layers of the retina especially the ganglion layer, while OLE(400 mg/kg) and MT prevent most of these changes. Therefore, OLE displays a major role as an antihyperglycemic and antihyperlipidemic, also it possesses curative role against DR, through its antioxidant and inhibition of AGEs in DM rats.