A histomorphologic analysis of pyrethroid pesticide on the cerebrum and cerebellum of adult albino rats

Abstract

Introduction: Pyrethroids Pesticide formulations are complex mixtures and some studies have associated their usage to predisposition to some degenerative diseases. This study was therefore aimed at investigating the sub-acute and acute histomorphologic effects of orally administered mixture of Allethrin, Imiprothrin and Phenothrin (P. pesticide) on the cerebrum and cerebellum of adult Wistar rats.

Materials and Methods: 80 adult Wistar rats of both sexes were divided into 5 groups of 15 rats each. Group I-III which was the treatment groups were further subdivided into 3 groups of 5 rats each while groups IV and V were normal and oil control respectively. The Pesticide was diluted with olive oil into 3 grades (75, 50 and 25% concentration) and orally administered to the rats of the treatment groups for 7, 21 and 40 days. The rats in group IV and V were given water and olive oil respectively for the duration of the treatment. At the end of the treatment, the rats were sacrificed by cervical dislocation. The brains were harvested and processed for histology using standard manual tissue processing techniques.

Results/Discussion: The behaviors exhibited by the animals included itching, twitch contraction, dilation of pupils, erected furs, tail suspension and increased salivation. Histological examination of the brain tissues revealed mild to marked distortion of the cyto-architectural patterns with multifoci of necrosis, severe gliosis involving predominantly astrocytes and olingodendrocytes both in the cerebral and cerebellar tissues.

Conclusion: In conclusion, this study showed that oral administration of P. pesticide resulted in several histomorphologic changes in the brain tissues in both dose and time dependent manner.

Keywords: Brain, cerebellum, cerebrum, histomorphologic, pyrethroids, Wistar rats