Histologic study on the protective effect of α-lipoic acid in sciatic nerve neurotoxicity induced by cypermethrin in albino rats

Abstract

Objective This work was undertaken to study the possible protective role of α-lipoic acid (ALA) in the sciatic nerve of rats intoxicated with the pesticide cypermethrin by histological and morphometric methods. Materials and methods Thirty adult male albino rats were randomly divided into five equal groups (six rats each): group I (control group) received no treatment, group II received daily 1 ml of corn oil orally, group III received 100 mg/kg of oral ALA daily, group IV received oral cypermethrin (75 mg/kg) daily, and group V received both ALA and cypermethrin. After 5 days treatment, both sciatic nerves were dissected out from each animal, and then semithin and ultrathin sections were prepared for light and electron microscopic examinations. Morphometric and statistical analyses were also conducted. Results After cypermethrine administration, the sciatic nerve showed nerve damage particularly affecting the myelinated nerve fibers. The lesions were manifested as axonal damage and changes in the myelin sheath. Myelinated nerve fibers were swollen showing Wallerian degeneration. Ultrastructurally, myelin sheaths exhibited fragmentation, vacuolations, and hyalinization. Axoplasm displayed shrinkage, vacuolations, fragmentations, myelin figures, and intra-axonal wide spaces, with swelling of Schwann cells. Unmyelinated fibers were minimally affected. Concomitant administration of ALA with cypermethrine displayed an observable protection against these changes. Conclusion ALA showed a protective effect against sciatic neurotoxicity induced by cypermethrin in albino rats.