Microanatomy, lipid peroxidation and antioxidant system of the visual cortex of rats following withdrawal from prolonged lead nitrate administration

Abstract

Exposure to lead (Pb) has been shown to alter the function of central nervous system and affect cholinergic neurons of the visual cortex in animal models. This study sought to investigate the withdrawal symptoms and oxidative stress on the visual cortex after lead exposure. A total of 20 healthy male Wistar rats were randomly divided into two groups (n=10): group A, control, received 10 ml/kg of distilled water for 30 days orally; group B, lead treated group, received 10 mg/kg of lead nitrate solution for 30 days orally. Group B was divided into two subgroups, group B1 serves as non-recovery while B2 serves as recovery (withdrawal). Five rats from each group were sacrificed under ether anesthesia 24 hours after the last oral administration of lead, while the remaining 5 rats (withdrawal subgroup) were sacrificed 30 days after the last oral administration of lead. The visual cortex was grossed from the brain tissue and processed for histology. Blood/serum samples were obtained and markers of oxidative stress (superoxide dismutase [SOD], catalase [CAT], glutathione peroxidase [GPX]), and lipid peroxidation (malondialdehyde [MDA]) were analyzed. Lead-exposed rats display a significant reduction in the SOD, CAT, and GPX level as well as increased in MDA level. However, following a recovery period, a non-significant improvement was seen in the histoarchitecture of the visual cortex.