Dose-dependent effect of thymoquinone on markers of oxidative stress in renal tissue of diabetic rats

Due to important role of enhanced oxidative stress in development of renal disorder in diabetes and with regard to antidiabetic and antioxidant effect of thymoquinone, this study was conducted to evaluate the effect of its administration on renal tissue level of some markers of oxidative stress in diabetic rats. In this experimental study, Wistar rats were divided into 5 groups, i.e. control, high dose thymoquinone-treated control (20 mg/kg), diabetic, and thymoquinone-treated diabetic groups (10 and 20 mg/kg). After 4 weeks, tissue level of malondialdehyde and nitrite and activity of superoxide dismutase (SOD) in kidney tissue were measured. Diabetic rats showed a significant increase in tissue level of malondialdehyde (p<0.01) and nitrite (p<0.05) and a significant reduction in SOD activity (p<0.05) and thymoquinone treatment at a high dose significantly reduced only levels of MDA and nitrite (p<0.05) and SOD activity in treated-diabetic groups was non-significantly higher as compared to diabetics. Chronic treatment with thymoquinone dose-dependently could attenuate some markers of oxidative stress in renal tissue from diabetic rats.