The present study was undertaken to determine if in vitro exposure to
mercuric chloride produces
reactive oxygen species (ROS) in the synaptosomes prepared from various regions of rat brain. The effects of in vivo exposure to
mercury on
antioxidant enzymes such as
superoxide dismutase (SOD) and
glutathione peroxidase (GPx) activities in different regions of rat brain were also investigated. Adult male Sprague-Dawley (CD) rats were dosed with 0, 1, 2.0 or 4.0 mg
HgCl2/kg
body weight, for 7 days. One week after the last dose, animals were sacrificed by
decapitation, their brains were removed and dissected and frozen in
dry ice prior to measuring the activities of these
enzymes. The results demonstrated that in vitro exposure to
mercury produced a concentration-dependent increase of ROS in different regions of the rat brain. In vivo exposure to
mercury produced a significant decrease of total SOD, Cu, Zn-SOD and
Mn-SOD activities in the cerebellum of rats treated with different doses of
mercury. SOD activity did not vary significantly in cerebral cortex and brain stem. GPx activity declined in a dose-dependent manner in the cerebellum with a significant reduction in animals receiving the 4 mg
HgCl2/kg
body weight. The activity of GPx increased in the brain stem while unchanged in the cerebral cortex. The results demonstrate that inorganic
mercury decreased SOD activity significantly in the cerebellum while GPx activity was affected in both cerebellum and brain stem. Therefore, it can be concluded that oxidative stress may contribute to the development of
neurodegenerative disorders caused by
mercury intoxication.