PROTECTIVE EFFECT OF VITAMIN E ON ENDOSULFAN-INDUCED OXIDATIVE CHANGES AND ASSOCIATED NEUROBEHAVIOURAL DEFICIT IN MALE WISTAR RATS

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Department of Medicine

ABSTRACT
Endosulfan is an organochlorine pesticide commonly used to control pests in vegetables, cotton, fruits and other agricultural produce. It is a contact and stomach insecticide toxic to mammals, fish and other aquatic organisms. Several reports have shown that it is a highly neurotoxic agent. The aim of this study was to evaluate the role of brain lipoperoxidation and oxidative stress in sensorimotor and cognitive changes, arising from endosulfan exposure in Wistar rats and the ameliorative potentials of vitamin E. Thirty two (32) male Wistar rats were randomly divided into four groups of eight (8) rats each: group I rats received soya oil at 2 ml/kg body weight; group II rats received vitamin E at a dose of 30 mg/kg body weight; group III rats received endosulfan at a dose of 12 mg/kg; and group IV rats received vitamin E (30 mg/kg) followed by endosulfan (12 mg/kg) after 30 mins. The regimens were administered orally by gavage once daily for 28 days. The rats were examined for neurobehavioural parameters: assessing motor endurance and neuromuscular coordination at weeks 0, 2 and 4; and for cognition 48 hrs to the termination of the study. At the end of the study period, the rats were euthanized. Brain homogenate samples were evaluated for malondialdehyde (MDA) concentration and activities of superoxide dismutase (SOD) and catalase (CAT). The results showed significant elevation (p < 0.05) in MDA concentration in the endosulfan-treated group compared to the vitamin E pre-treated group; a significant increase in CAT activity in the endosulfan-treated group (p < 0.05) compared to the control group, and no significant change in SOD activity in all the groups. Endosulfan-treated rats showed decreased motor endurance and neuromuscular coordination, compared to that of the control rats and rats in other treatment groups; although the difference was not significant (p > 0.05). No significant difference (p > 0.05) was recorded for the learning acquisition in all treatment groups, although rats in the endosulfan-treated group showed an impaired ability to learn. However, the ability of the endosulfan-treated rats to retain memory was significantly impaired (p < 0.05) when compared to the vitamin E treated rats. The results showed that endosulfan induced oxidative stress, impaired motor skills and short term memory acquisition and retention, which were ameliorated by vitamin E treatment in male Wistar rats.