Developmental Effects of Perinatal Lead Exposure on the Cerebellum of Wistar Rat Pups

Abstract

Lead (Pb) exposure is a persistent global health problem, with the heaviest burden in developing regions such as Africa. In Nigeria, repeated cases of Pb poisoning due to mining and environmental contamination have raised serious public health concerns. The cerebellum, which plays a critical role in motor coordination, balance, and cognitive processes, is highly susceptible to toxic insults during development. However, the specific timing of Pb exposure that produces the greatest cerebellar damage remains uncertain. This study examined the timingdependent neurotoxic effects of Pb acetate on the histology of the developing cerebellum in Wistar rats, with emphasis on structural alterations. Twenty-four Wistar rats were assigned into four groups: control, prenatal Pb exposure, postnatal Pb exposure, and gestation-through-lactation Pb exposure groups. Lead (500 ppm) was administered through drinking water during the designated exposure periods. Following sacrifice, brain tissues 
were harvested, fixed, and processed for histological examination of the pons using hematoxylin and eosin staining. Photomicrographs were examined for histopathological changes. The control group showed normal cerebellar cytoarchitecture with intact Purkinje cell, molecular, and granular layers. Pb-exposed groups exhibited marked neuropathological alterations including Purkinje cell degeneration, fibrosis, pyknosis, karyolysis, karyorrhexis, astrocytosis, perineural vacuolation, vascular congestion, and areas of necrosis. These 
findings indicate that Pb disrupts cerebellar integrity in a timing-dependent fashion, with combined prenatal and postnatal exposure causing the most severe damage. Pb acetate exposure during vulnerable developmental windows induces profound cerebellar damage, characterized by neuronal loss, vascular changes. The perinatal 
stage appears to be the most sensitive period for Pb-induced neurotoxicity. These results underscore the need for strict preventive measures to minimize early-life Pb exposure and its long-term neurodevelopmental consequences.