Effect Of Selenium And Oxidative Stress Inducers On Sevaral Selenoproteins MRNA Expression Of Endothelial Cell

Selenium (Se) is an essential trace element and functions primarily in the form of selenoproteins. The intake of Se can to be inversely correlated with the incidence of atherosclerosis and coronary heart disease. Oxidative damage to the endothelium is thought to be a primary event in the pathogenesis of atherosclerosis and Se, added as selenite, can protect the endothelium cells from such damage by altering the expression of specific selenoproteins.In this paper, the effect of sin-1 and H₂O₂ on the mRNA levels of several selenoproteins and the protections by sodium selenite were investigated. The main results are as follows:1) The effects of Na2SeO3, H₂O₂ and SIN-1 on the cell viability of ECV304 cells were investigated by MTT assay. The results showed that lower dose (0.1⁰.3 mM) of Na2SeO3, H₂O₂ and SIN-1 had no significant effect on the cell viability, higher dose of them could induce acute cytotoxicity and aggravated as doses increased. The effect of H₂O₂ and SIN-1 on SelS mRNA expression in ECV304 cells and the role of selenium were examined by RT-PCR. The results indicated that SelS mRNA expression was highly increased by lower dose (0.1⁰.3 mM) of H₂O₂ and SIN-1 in ECV304 cells, and then decreased by higher dose of them. It was showed that the mRNA level of SelS had a significant increase when ECV304 cells were treated with an adaptive dose of selenium at indicated concentration after exposured to H₂O₂ or SIN-1.2) The effect of H₂O₂ and SIN-1 on glutathione peroxidase (GPx1) and thioredoxin reductase (TR1) mRNA expression in ECV304 cells and the role of selenium were examined by semiquantitative RT-PCR. The results indicated that SelS mRNA expression was highly increased by lower dose (0.1⁰.2 mM) of H₂O₂ and SIN-1 in ECV304 cells, and then decreased by higher dose of them. Furthermore the mRNA level of TR1 had a significant increase when ECV304 cells were treated with an adaptive dose of selenium at indicated concentration after exposured to H₂O₂ or SIN-1. However, H₂O₂ and SIN-1 could down regulated GPx1 mRNA expression, and these effects were partially reversed by selenium. The effects of H₂O₂,SIN-1 and selemium on the GPx1 were consisitent with the level of GPx1 mRNA expression.