Exposure to Insecticide Mixture of Cypermethrin and Dichlorvos Induced Neurodegeneration by Reducing Antioxidant Capacity in Striatum

Abstract

To evaluate the effect of cypermethrin (CP) and dichlorvos (2,2-dichlorovinyl dimethyl phosphate, DDVP) on the striatum of adult Wistar rats. Thirty-two animals were grouped into 4; group A (control) inhaled fresh air, and groups B, C, and D were exposed to a formulation of 5 mm^-1 (4.4 ppm) of dichlorvos and 10 mm^-1 (8.7 ppm) of cypermethrin insecticide for 2hrs/day, 3hrs/day and 4hrs/day respectively. We utilized the wire suspension test to demonstrate the neurobehavioral changes across the four groups of animals to identify the animal groups that have lost their motor function. Following the neurobehavioral test, the animals were weighed, anesthesized and dissected for brain tissue harvesting. Half of the brain tissue was frozen for biochemical analysis while the other part was fixed in 10% Neutral Buffered Formalin for two days and grossed to isolate the brain tissue of interest for histopathology. The results from the neurobehavioral studies show a significant decrease in motor function of the experimental groups. There was a significant elevation in the malondialdehyde and glucose levels of all the exposed groups, while their various antioxidant levels decreased significantly (p<0.05). Histopathological features were observed across the exposed groups ranging from the presence of vacuolated neuronal cells, neuronal cell shrinkage, and chromatolysis, which characterize the neurodegenerative effect of cypermethrin and dichlorvos on the striatum. This study indicates that a combined administration of cypermethrin and dichlorvos exerts a neurodegenerative effect on the striatum of adult Wistar rats.