The Neurotoxic Impact of Formulated Pyrethroid Insecticide on the Substantia Nigra of Adult Wistar Rat

Pyrethroid toxicity has been reported in animal models and some cases of poisoning have been reported in humans. This research was aimed at evaluating the effects of formulated pyrethroid insecticide on the substantia nigra of adult Wistar rat. Thirty two (32) adult Wistar rats were divided into 4 groups, group A (control) inhaled fresh air, group B (short-term), group C (medium-term) and group D (high-term) were exposed to 10% formulated pyrethroid for 2hrs/day, 3hrs/day and 4hrs/day respectively for five times a week in four weeks. Wire suspension test was utilized to demonstrate the motor function. The brain tissues were homogenized for biochemical analysis while some tissues were fixed in 10% Neutral Buffered Formalin for 48hrs and grossed to isolate the brain tissue of interest for histological investigations. The neurobehavioral test presents statistical non significant decrease in the motor function of the exposed groups when compared to the control group (p<0.05). The malondialdehyde and glucose level of the exposed groups were significantly higher, while the total antioxidant capacity in the exposed groups were significantly lower. Mild to severe histopathological features were observed in the exposed groups which suggests substantia nigra. Neuronal degeneration on exposure to formulated pyrethroid. This study indicates acute exposure of formulated pyrethroid in rats exacts neurodegenerative changes in the substantia nigra via elevation of oxidative stress and depletion of antioxidant capcity. Thus, further studies should be carried out to demonstrate the long-term effect as well as the mechanism of action of formulated pyrethroid insecticide induced degeneration on the substantia nigra.