Owoeye O, Edem VF, Akinyoola BS, Rahamon SK, Akang EE, Arinola OG. Histological changes in liver and lungs of rats exposed to dichlorvos before and after vitamin supplementation. European Journal of Anatomy 2012; 16(3): 190-198.

ABSTRACT

This study evaluated the effect of vitamins with antioxidant activity on the effect of Dichlorvos (2, 2-dichlorovinyl dimethyl phosphate), an organophosphorus compound used in pest control on mammalian organs. Literature is scanty on the histopathological effects of inhalationally administered dichlorvos, especially of the formulations used in Nigeria. The objective of the study is to evaluate these effects on vital organs, with a view to proffering solutions to ameliorate the effects.

Fifty Wistar male rats were divided into 10 groups of 5 rats each. A group served as control, while the other groups were exposed to dichlorvos for between 1-6 weeks in a poorly ventilated compartment. The last three groups in addition to dichlorvos exposure received supplementation with vitamin C, E or red palm oil (RPO). Exposure to dichlorvos was done for 4 hours daily. At completion of exposure, animal tissue was processed by the routine method for paraffin wax and stained sections were examined under the light microscope.

Histopathological studies of the lung showed extension in the width of bronchial associated lymphoid tissue (BALT), mild generalized congestion of the peri-bronchiolar and inter-alveolar septum as compared with the control. These observations were much reduced in the vitamin-treated groups. Similarly, histopathological studies of the liver showed diffuse vacuolar degeneration of hepatocytes with peri-portal cellular infiltration by mononuclear cells, vacuolar degeneration and necrosis of hepatocytes when compared with the normal. These changes were significantly reduced in the vitamin-supplemented groups.

In conclusion, inhalationally absorbed dichlorvos caused histopathological changes in the lung and liver of rats, but these were ameliorated by co-treatment with vitamin supplementation. The changes provide the histological basis for further work and counselling on careful use of dichlorvos for domestic and agriculture, especially in enclosed areas.