Diabetes mellitus (DM) is a chronic health problem with a growing spread universally. Diabetes poses severe health complications,
including neuropathy, cardiomyopathy, and ocular difficulty which is a typical complaint between diabetic subjects. Virgin olive oil is
a natural product rich in phenols and other antioxidants. It is commonly recognized to protect against numerous ailments and
disorders, including diabetes. The main objective of the present study was to investigate the possible protective role of virgin olive
oil against diabetic induced corneal histopathological changes in streptozotocin (STZ) induced diabetic rats. Furthermore, the
underlined mechanism was investigated regarding the antioxidant’s capacity. Diabetes was induced by giving a single
intraperitoneal (i.p.) injection of STZ (40 mg/kg bw). Twenty-four male Sprague-Dawley rats were allocated in 4 equal groups: nondiabetic
control, STZ- diabetic, diabetic and olive oil (1.0 ml/100 gmbw/day), and diabetic and metformin (500 mg /kg/bw/day). The
experiment design for treatment last for six weeks. Pathological examination of the corneal tissue was used to ascertain the potential
protective effect of virgin olive oil against the damage associated with diabetes. The results of this study showed a glycemic and
glycated hemoglobin lowering effect of virgin olive oil and metformin in STZ-induced diabetes. Moreover, olive oil and metformin
reduced the lipid peroxidation product and increased the level of total antioxidants capacity. Furthermore, this study showed an
ameliorative effect of olive oil on diabetic induced corneal histopathological complications. In conclusion, olive oil seemed to protect
against diabetic induced changes in rat’s cornea as it maintained epithelium integrity and prevented keratinization and stroma
neovascularization via both controlling blood glucose level and most probably via antioxidant activity.
Keywords: Diabetes, olive oil, metformin, HbA1c, glucose, antioxidant, cornea, histopathology