Lead induces inflammation and neurodegenerative changes in the rat medial prefrontal cortex

Abstract

Objectives: Lead (Pb) is a neurotoxicant heavy metal ubiquitously present in the eco-system. The precise mechanism by which Pb confers its deleterious effects on the cellular profile of the central nervous system remains unknown. The aim of this study was to investigate the effect of Pb on the medial prefrontal cortex (mPFC) using histological, immunohistological and morphological techniques.

Methods: Thirthy juvenile male Wistar rats were used in this study. The rats were randomly assigned into three groups. Group A served as the control group, Group B received 5 mg/kg Pb-nitrate (PbNO3) orally for 21 days, and Group C received 5 mg/kg PbNO3 and left for an additional 21 days to recover.

Results: There was a significant decrease in the number of normal neurons in the mPFC of the PbNO3-treated rats. The number of degenerating neurons significantly increased in the PbNO3-treated groups compared with the control group. A marked increase was observed in the number of astrocytic cell count in the PbNO3-treated groups compared with the control. The neuronal cells in the cytoarchitectural profile of the mPFC of the rats receiving PbNO3 showed marked neurodegenerative modification with features of distorted morphology, swollen and vacuolized cytoplasm, and features of either pyknotic or karyorrhectic nuclei. The cytoarchitecture of the mPFC of the rats in the control group preserved the normal histological outline suggestive of a normal and functional mPFC.

Conclusion: Exposure to Pb ingestion can result in significant inflammatory responses in the cytoarchitectural profile of the mPFC. Furthermore, 21 days of cessation of exposure to PbNO3 did not halt or reverse the deleterious effects of Pb on the mPFC of the rats, suggesting that Pb persists in the central nervous system of the rats.

Keywords

• astrogliosis
• cell death
• heavy metals
• neurodegeneration
• pathology

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