AN INVESTIGATION OF THE TOXICITY OF LINDANE IN VIVO AND IN VITRO

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Date
1997-09
Authors
BABAYE, YUSUF
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Abstract
The goal of this project is to study in vivo and in vitro, the mode of toxicity of lindane (an organochlorine insecticide) at tissue/cellular level with the hope diat the information obtained would provide an insight into the non-target toxicity of the compound. The in vivo investigation involved acute and chronic toxicity studies. In the acute toxicity studies, the median lethal dose (LD50) of lindane using the intraperitoneal (I.P.) route was determined as 25.4 mg/kg. The symptoms of toxicity were scored and were found to be dose-dependant and mainly those of central nervous system (CNS). In the chronic toxicity studies, results of the histopathological examination of sections of the rat brain exposed to feeds contaminated with lindane indicated lesions of different structures. There was vacuolations, necrosis of the oligodendroglial cells and some degree of neuronal degeneration especially in the brain of rats exposed to the contaminated feeds for a long period of time (4 to 12 weeks). Electroencephalographic (EEG) pattern of rats fed on contaminated feeds showed some degree of desynchronisation as compared to the control. The effect was found to increase with dose and time of exposure. Since desynchronisation of EEG pattern is associated with increased CNS activity, it is possible that chronic exposure to lindane may produce symptoms of CNS stimulation. The in vitro investigation was aimed at evaluating the role of sodium ions (Na+) in the neurotoxicity of lindane. It was found that lindane dose-dependently attenuated the effect of lignocaine (P< 0.001) on both the rabbit ileum and phrenic nerve preparations. It was suggested that lindane increases the permeability of the membrane to Na+ thereby interfering with the generation and propagation of action potential. The importance of identifying the mechanism by which various chemicals produce their toxicity cannot be overemphasized; in order to design a rational basis for treatment and to make available adequate information necessary in the prevention, diagnosis and management of intoxication.
Description
A Thesis in the Department of Pharmacology and Clinical Pharmacy Submitted to the Postgraduate School in partial fulfillment of the requirements for the Degree of Master of Science in Pharmacology Ahmadu Bello University, Zaria - Nigeria
Keywords
INVESTIGATION,, TOXICITY,, LINDANE,, VIVO,, VITRO
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