Astaxanthin Attenuates Oxidative Damage in Retina by Potentiation of the Antioxidant Capacity in Experimental Model of Diabetic Retinopathy

Background: astaxanthin is a natural carotenoid, which is belonged to the xanthophylls family. previously, the powerful antioxidant properties of this compound have been demonstrated in several biological environments. objectives: as overproduction of reactive oxygen species (ros) has a critical role in the pathophysiology of diabetic retinopathy (dr), we aimed to evaluate the effects of astaxanthin on the antioxidant capacity of retina in experimental model of dr. methods: forty eight rats were randomly divided into four groups (n=12 for each group); normal, diabetic, and two treated normal and diabetic groups. diabetes was induced by a single intravenous injection of streptozotocin (50 mg/kg). rats with blood glucose >500 mg/dl were selected as diabetic animals. treatment groups were treated with astaxanthin (20 mg/kg/day, orally) for six weeks. at the end, the eyeballs were removed under deep anesthesia and then the retinal tissues were quickly frozen for assessment of the glutathione and malondialdehyde contents as well as superoxide dismutase (sod) activity. results: malondialdehyde levels of the retina in diabetic rats increased significantly (16%), whereas the glutathione levels decreased (85%), (p<0.05). astaxanthin significantly increased the glutathione content of retina in treated diabetic rats by 77% compared to untreated rats (p<0.05). diabetes also increased the activity of sod in retina. treatment with astaxanthin enhanced the sod activity both in treated normal and diabetic rats (p<0.05). conclusion: our findings reveal that astaxanthin can decrease oxidative damage of retina by improving the antioxidant capacity in diabetic rats, which may ultimately delay the appearance of dr.