Caracterização da injúria no córtex motor de ratos em um modelo de exposição crônica ao metilmercúrio (MeHg)

Abstract

The mercury is an environmental contaminant which poses a great risk to human health. Exposure to this toxic metal occurs mainly through a diet contaminated by methylmercury (MeHg) in low concentrations and over a long period of time. Thus, in this study we propose an assessment of the effects of MeHg on the motor cortex in an animal model of chronic exposure and low dose, similar to dietary exposure in areas of high environmental toxicity of mercury. Adult rats were exposed to MeHg for 60 days with a dose of 0.04 mg/kg/day, while the control group received only the vehicle. After this period, they were subjected to behavioral testing in order to evaluate the motor performance after mercury exposure, and then sacrificed and evaluated for oxidative biochemical parameters (change in the concentration of nitrite - NO Lipid Peroxidation - LPO and Antioxidant Capacity Total) as well as evaluation of total deposits of mercury in the motor cortex and changes in cell density of neurons and astrocytes. Data were tabulated and statistically analyzed by Student's t-test (p <0.05). It was possible to observe total mercury deposits in the motor cortex, and deficits in motor parameters, with a reduction in the overall locomotion, on balance and increase in the number of failure, coupled with a significant increase in the levels of NO and LPO and decreased ability antioxidant full of animals exposed, reducing the population of astrocytes and neurons compared to control animals these findings suggest that exposure of adult animals to MeHg, even at low dose and chronically, causes changes in the motor cortex with damage to their functions.