The effect of sulfur dioxide inhalation on visual evoked potentials, antioxidant status, and lipid peroxidation in alloxan-induced diabetic rats

The aim of the study was to investigate the effect of 10 ppm sulfur dioxide (SO2) exposure on visual evoked potentials (VEPs), thiobarbituric acid rea ctive substances (TBARS), and the activities of Cn,Zn superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) in diabetes mell itus. Forty healthy male albino rats, aged 3 months, were divided into four equal groups: control (C), sulfur dioxide + control (CSO2), diabetic (D), and sulfur dioxide + diabetic (DSO2) groups. Experimental diabetes mellitus was induced by IV injection of alloxane monohydrate in a dose of 50 mg/kg body weight. Ten ppm sulfur dioxide was administered to the animals of sulf ur dioxide-exposed groups in an exposure chamber for 1 h/day x 7 days/week x 6 weeks while control and diabetic groups were exposed to filtered air in the same condition. SO2 exposure, though markedly decreasing retina CAT an d GSH-Px activities, significantly increased retina Cu,Zn-SOD activity in t he diabetic and nondiabetic groups. In contrast to SO2-related increase in the activity of Cu,Zn-SOD, decrease in GSH-Px activity was observed in the brain of those groups. Brain CAT activity was unaltered. SO2 exposure cause d the significant elevation in brain TBARS levels of CSO2 and DSO2 groups, whereas only in the retina TBARS level of the CSO2 group. SO2 exposure caus ed the significant prolongations of P-1, N-1, P-2, and P-3 components of VE Ps in the nondiabetic and all components of VEPs in the diabetic groups. SO 2 exposure also resulted in significant amplitude reductions in both experi mental groups.