Studies Of Effects Of Sodium Selenite On Mercury-Poisoned Rat

ObjectiveMercury (Hg) is a highly toxic heavy metal, which poses a severe risk to human health and ecological environment. Methylmercury is the most toxic form of mercury. Selenium(Se) is an essential element,but is toxic at certain level to organisms. The antagonism between selenium and mercury has been founded for a long time. The aim is to explore effect of sodium selenite on methylmercuy poisoned rats.MethodsWe firstly established methylmercury-poisoned rats model by gavage.The three different doses of sodium seleniute was supplemented to the rats by gavage every other day. The changes of general indicators,including biological behaviors, weight gains,organ coefficients,biochemical indexes including MDA and GSH-Px and the selenium and mercury content in liver and urine were studied.Results1General index determination:(1) Weight gains:mercury exposure could significantly reduce the weight gains of rats. Compared with the control group, Se supplementation at each dose group of Se could increase the weight gains.(2) Organ coefficients:Selenium supplementation could significantly increase the organ coefficient of the kidney ang brain.2Biochemical indexes:(1) MDA:The contens of MDA increased significantly in liver and kidney in the methylmercury-exposed rats. When supplemented with Se for60days, each dose group could significantly reduce the contens of MDA in the liver.There is no significant difference between Se supplementation groups and the control group in the renal MDA level.(2)GSH-Px:After The GSH-Px activity reduce significantly in liver and serum when exposed to methylmercury. After supplementation of Se for30days, each dose group of Se could significantly increase GSH-Px activity in the liver. The GSH-Px activity increased significantly in the serum when supplemented Se for60days.3Se and Hg content in the organs: The Hg and Se contents increased significantly in kidney and liver after exposure to methylmercury, while the Hg content increased significantly in brain but not the Se. When supplemented with sodium selenite, there is no significant difference between each dose group of Se and model group in kidneys. After supplementation for60days, The high-Se dose could significantly increase Hg content in livers. The high and middle dose of Se could increase significantly the Hg content in brain.Conclusion1MeHg could accumulate in different organs,with an order of kid ney>liver>brain.2Sodium selenite can reduce oxidative injury of organim, increase antioxidant enzyme activities.3The mercury and selenium are positively correlated in the liver and the brain, and negatively correlated in the kidney. As the contens of Se-increased, the contens of Hg had no significant in the kidney but increased in the liver and brain.