Developmental exposure to organophosphate insecticide is
well known to induce neurobeha-vioral impairments, at late period. The present
study aims to investigate the effects of chronic exposure to Malathion, from in
utero to young adult stage, on locomotor skills and anxiety like- behavior
among wistar rat. Four groups of female rats, bred with one non-pesticide
exposed male, are used. On gestational day
6, three groups receive daily, by intragastric gavage, 3 different doses
of Malathion dissolved in corn oil (100, 200 and 300 mg/kg body weight). The
control group receives the corn oil only. On postnatal day 21, weaned
offsprings are submitted to the similar treatment until adult age. Spontaneous
locomotor activity is evaluated using the Open-Field test (OF) and anxiety-like
behavior is measured using both Open-Field (OF) test and Elevate Plus-Maze
(EPM). Malathion at 300 mg/kg is toxic to pregnant dams, and pups are stillborns.
In males, Malathionlevelat 100 and 200 mg/kg induced significant impairment of
spontaneous locomotor activities, which is reflected by high decrease of number
of squares crossed in OF. In contrast, no discernible changes are observed within females Malathion-treated-group. However, females exposed to both malathion levels develop further anxiety-like
response, expressed by significant reductions of exploratory activities in OF
and time spent in open arm of EPM. Neurochemistry assay shows that cerebellum
and neocortex acetylcholinesterase (AChE) activity
inhibition are significantly increased with neurobehavioral deficits in
males, relative to females. Overall, neurobehavioral outcomes of current
study reveal that developmental exposure to Malathion induces sex-selective effects
with greater changes in females.