Enhanced Zinc Intake Protects against Oxidative Stress and Its Consequences in the Brain: A Study in an In Vivo Rat Model of Cadmium Exposure

We examined, in a rat model of moderate environmental human exposure to cadmium (Cd), whether the enhanced intake of zinc (Zn) may protect against Cd-caused destroying the oxidative/antioxidative balance and its consequences in the brain. The intoxication with Cd (5 mg/L, 6 months) weakened the enzymatic (superoxide dismutase, glutathione peroxidase, catalase) and non-enzymatic (total thiol groups, reduced glutathione) antioxidative barrier decreasing the total antioxidative status and increased the concentrations of pro-oxidants (hydrogen peroxide, myeloperoxidase) in this organ and its total oxidative status. These resulted in the development of oxidative stress and oxidative modifications of lipids and proteins. The co-administration of Zn (30 and 60 mg/L enhancing this element intake by 79% and 151%, respectively) importantly protected against Cd accumulation in the brain tissue and this xenobiotic-induced development of oxidative stress and oxidative damage to lipids and proteins. Moreover, this bioelement also prevented Cd-mediated oxidative stress evaluated in the serum. The favorable effect of Zn was caused by its independent action and interaction with Cd. Concluding, the enhancement of Zn intake under oral exposure to Cd may prevent the oxidative/antioxidative imbalance and oxidative stress in the brain and thus protect against injury of cellular macromolecules in the nervous system.