Mercury-Induced Oxidative Stress and Neuropathologic Changes in the Prefrontal Cortex of Wistar Rats

Abstract

Access to clean water is necessary for human, animal, and environmental health. Anthropogenic human activities such as mining, agriculture, and continuous pollution from industrial waste, as well as population growth, continue to compromise the quality of water. The neurodegenerative impact of mercury with a similar concentration as obtained from waterways on the prefrontal cortex of Wistar rats was studied. Twenty adult rats were randomised into two groups: a control group and a 0.001 mg/L mercury (II) thiocyanate (Hg(SCN)2) group, ad libitum for 65 days, after which the animals were euthanised via cervical dislocation. Blood and tissue samples were obtained for analyses of oxidative stress biomarkers: superoxide dismutase (SOD), glutathione peroxidase (GPx), malondialdehyde (MDA), hydrogen peroxide (H2O2), histological, and glial fibrillary acidic protein (GFAP) and inducible nitric oxide synthase (iNOS) immunohistochemical evaluation. Statistical data were analysed using a t-test, set at p < 0.05. When comparing the mercury-treated groups to the control, a significant difference was observed in the SOD, GPx, MDA, and H2O2 values, with cellular alterations evident in the mercury-treated rats. Additionally, mercury treatment resulted in the distortion of the cortical histoarchitecture with intense immunoreactivity of GFAP and iNOS suggesting neuroinflammation. This study highlighted that mercury exposure induced oxidative stress and led to distortion in the histoarchitecture of the prefrontal cortex of adult Wistar rats.