Garlic extract attenuates retinal oxidative stress and IL-1 expression in STZ-induced diabetic rats

Abstract

Retinopathy is one of the most common complications of diabetes. Hyperglycemia damages to the tissues through induction of oxidative stress and inflammation. In this study, the effects of garlic extract on the oxidative stress status and interleukin1 beta (IL-1β) mRNA and protein levels in the retinal tissue of diabetic rats were investigated. Twenty-four male Wistar rats were divided into four groups: control rats (C), diabetic rats (D), garlic treated diabetic rats (D+G), and garlic treated normal rats (G). At the end of the treatment period, for determination of oxidative stress, lipid peroxidation (LPO), thiol group (SH), total antioxidant capacity (TAC), and total oxidant status (TOS) were assayed. The expression of mRNA and protein levels of IL-1β was determined in retinal homogenates by real-time PCR and ELISA, respectively. In diabetic rats, TAC and thiol group decreased (p<0.05 and p<0.001, respectively), whereas TOS and LPO increased (p<0.001 and p<0.01, respectively) compared with control rats. In garlic treated diabetic rats TAC and thiol group increased (p<0.05 and p<0.001, respectively), whereas TOS and LPO decreased (p<0.001) compared with untreated diabetic rats. The mRNA expression and protein levels of IL-1β increased in diabetic rats in comparison with control group (p<0.001). These parameters decreased in garlic treated diabetic rats compared with untreated diabetic rats (p<0.05 and p<0.001, respectively). These results indicate that garlic extract has antioxidant property, can decrease IL-1β protein and mRNA level, and therefore, it can be a good candidate for reduction of diabetic retinopathy.