Brain, lung, and heart oxidative stress assessment of an over-the-counter pyrethroid insecticide product in Nigeria

We evaluated the brain, lung, and heart oxidative stress in rats exposed to aerosol of an over-the-counter pyrethroid insecticide product in Nigeria. The experimental animals were randomly divided into four groups: group I (control) was not exposed to the insecticide aerosol, while groups II, III, and IV were exposed to 6.0 mL m^-3, 12.0 mL m^-3, and 18 mL m^-3 of insecticide aerosol respectively. Exposures were carried out in wooden-glass chambers one hour daily for six weeks. Malondialdehyde (MDA) and reduced glutathione (GSH) concentrations, as well as catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione S-transferase (GST) activities were determined. The brain, lung, and heart showed no significant difference in their weights and relative weights compared with the control. A significant increase in brain lipid peroxidation (LPO) was seen in groups III and IV, while there was no significant increase in lung and heart LPO compared with control. Significant decrease in the brain and lung GSH were observed in all the treatment groups when compared with the control, but only group IV showed significant reduction in heart GSH. Also, activities of lung GST and SOD were decreased compared with control, while the activity of GPx in the lung was significantly increased in group III. Lastly, non-significant increase in lung CAT activity was recorded in groups II and III, but decreased in group IV compared with control. Prolonged and incessant exposure to the insecticide aerosol over a long period of time may lead to tissue oxidative stress. These findings suggest that the use of insecticide aerosol for domestic purposes should be regulated.

Keywords
Insecticide aerosol; pyrethroid; oxidative stress; lipid peroxidation; rats