AIG-UNUIGBE, JOHNFAVOUR EHIJIAGBON

Cerebellar disorders are a class of neurological impairments characterized by unsteady gait anduncoordinated movements, typically resulting from lesions or pathologies affecting the cerebellum. These disorders may arise from congenital anomalies, hereditary ataxias, or exposure to environmental neurotoxicants such as heavy metals. Mercury, a highly toxic heavy metal, is known to exert deleterious effects on the central nervous system. Its lipophilic nature enables it to cross the blood-brain barrier, where it accumulates and induces oxidative stress, leading to neuroinflammation, neuronal damage, and impaired motor coordination. Dietary antioxidants have shown promise in combating mercury-induced neurotoxicity. Accordingly, this study investigated the activity of ethanol extract of Pleurotus ostreatus (P. ostreatus) against mercuric chloride (HgCl2) induced cerebellar toxicity in Wistar rats. In this study, fortytwo (42) Wistar rats were randomly assigned into six groups (A-F). Group A rats served as control; Group B received 4 mg/kg body weight [bw] of HgCl2 only; Group C received 4 mg/kg bw of HgCl2+ 250 mg/kg of P. ostreatus; Group D received 4 mg/kg bw of HgCl2 + 500 mg/kg of P. ostreatus; Group E received 250 mg/kg bw of P. ostreatus only and Group F received 500mg/kg bw of P. ostreatus only. All administrations were done orally for twenty-eight (28) days. Neurobehavioural activity was subsequently evaluated using the Open Field, String, Movement Initiation and Step Tests. Following the assessments, the experimental rats were sacrificed via cervical dislocation and the cerebellum harvested for antioxidant enzymes activity, lipid peroxidation, mercury concentration and histological assessments. The findings revealed that rats exposed to HgCl2 exhibited significant (p <0.05) weight loss, motor deficit, impaired antioxidant defense, elevated lipid peroxidation, elevated mercury levels and degeneration of Purkinje cells and molecular layer neurons. However, co-administration with P. ostreatus significantly (p < 0.05) mitigated these mercury-induced cerebellar alterations in Wistar rats. Overall, the findings from this study indicate that P. Ostreatus mitigates mercuric chloride-induced cerebellar toxicity, primarily through its antioxidant, neuroprotective, and metal-chelating properties, thus making it a promising agent for the development of novel therapeutic strategies aimed at managing mercury neurotoxicity and its associated motor impairments.