Immunotoxicological Investigation of The Intracranial Auditory Centers In Pyrethroids Formulation Treated Wistar Rat

Purpose: The use of pesticides and their potential impact on public health are of great concern. Recent studies on the pathophysiology of neurodegenerative diseases have suggested that chronic exposure to pyrethroids could be associated with alterations in the central auditory pathways. This study was therefore aimed at evaluating the neurotoxicity of pyrethroids on the intracranial auditory relay-centers in adult wistar rats. Methods: Forty adult wistar rats of both sexes with average weight of 180g were assigned into five groups (n=8). Groups A, B, and C were treated with known pyrethroids formulation containing Cyfluthrin, Imiprothrin, and Prallethrin, diluted with olive oil to form 25%, 50% and 75% concentrations. Groups D and E were administered distilled water and olive oil once treatment negative and positive controls, respectively. The treatment lasted for duration of forty days. At the end of the duration, all animals were sacrificed by cervical dislocation, after which the inferior colliculi (IC), medial geniculate bodies (MGB) and cerebellum were harvested for histology and immuno histochemistry using calbindin and palvalbumin antibodies. Results: Histologically, there was slight degeneration of neuronal cells and vacuolated cytoplasm, dispersed distribution of nissl bodies in several cells of MGB and IC of the treated groups compared to the controls. In the cerebellum, there was abnormal proliferation of cells in the purkinje layer with poor distribution of nissl bodies when compared to control groups. Immuno histochemistry further revealed decreased immuno-reactivity of Calbindin2 and Parvalbumin in the treated tissues compared to the control groups. Conclusion: Pyrethroids influences motor coordination and balance of rats, and also the function of the auditory relay-centres.