Effect Of Selenium And Oxidative Stress Inducers On SelS MRNA Expression

Diabetes is an inflammatory disease and one of the most serious diseases in human. SelS is closely related with diabetes. The researches on SelS and its effect on the pathogenesis, the prevention and cure of diabetes are one of the frontier fields in human health. The potential preventive and therapeutical effects of the essential trace element selenium on diabetes are concerned, but the mechanisms of them remain elusive.To investigate the the effect of SelS and selenium on the development of diabetes, HepG2 cells and alloxan-induced diabetic Wistar rats were acted as research objects in this paper. The main results are as follows:1) The effects of Na2SeO3,β-mercaptoethanol (β-ME), ONOO? and SIN-1 on the cell viability of HepG2 cells were investigated by MTT assay. The results showed that lower dose of Na2SeO3,β-mercaptoethanol (β-ME), ONOO? or 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 selenium onβ-ME-induced apoptosis was investigated by DNA ladder analysis. The results suggested thatβ-ME induced apoptosis in a dose-dependent manner. Apoptosis could be triggered by higher concentrations ofβ-ME and aggravated as doses increased. An adaptive dose of selenium redounded to alleviatedβ-ME induced apoptosis. The effect ofβ-ME, ONOO? and SIN-1 on SelS mRNA expression in HepG2 cells and the role of selenium were examined by RT-PCR. The results indicated that SelS mRNA expression was highly increased by lower dose ofβ-ME, ONOO? and SIN-1 in HepG2 cells, and sharply decreased by higher dose of them. Meanwhile, SelS mRNA expression has a significant increase after pretreatment with an adaptive dose of selenium at indicated concentration of them. The two RT-PCR, semiquantitative RT-PCR and quantitative real time RT-PCR, were used to examine the effect of SIN-1 on SelS mRNA expression in HepG2 cells. The results illustrated that the two variance tendencies were similar, though there was slightly difference in quantity. 2) The effect ofβ-ME, ONOO?, SIN-1 on glycogen synthase (glgA) and glycogen phosphorylase (glgP) mRNA expression in HepG2 cells and the role of selenium were examined by semiquantitative RT-PCR. The results indicated that the trace element selenium andβ-ME had no significant effect on glgA, glgP mRNA expression. However, ONOO? and SIN-1 could cause glgA, glgP mRNA expression disturbance, and an adaptive dose of selenium played a role in inhibiting this disturbance. Following with the occurrence of apoptosis, higher dose of selenium,β-ME and ONOO? sharply decreased glgA, glgP mRNA expression in HepG2 cells.3) Three consecutive intraperitoneal injections method was applied to induce diabetic model. The results indicated that alloxan-treated rats displayed the typical complications of diabetes such as polyuria; polydipsia; hyperphagia and emaciation, the experimental rats′whole-blood glucose level were over 16.7 mM, and the success rate was 60%. The variation of SelS, glgA, glgP mRNA expression in liver and SelS mRNA expression in adipose tissue, skeletal muscle and pancreas of alloxan-induced diabetic Wistar rats after fasting were examined by semiquantitative Reverse Transcription Polymerase Chain Reaction (semiquantitative RT-PCR). The results showed that, compared with the control, hepatic SelS and glgP mRNA expression of the diabetic rat model were increased significantly; but hepatic glgA mRNA expression of it was decreased significantly. Meanwhile, there were no significant difference of SelS mRNA expression in adipose tissue and skeletal muscle between the diabetic rat model and the control. However, SelS mRNA expression in pancreas of the diabetic rat model was increased significantly, compared with the control. The contents of lipid peroxidation products in liver of the two groups were investigated by thiobarbituric acid (TBA) method. The results suggested that the content of lipid peroxidation products in liver of the diabetic rat model was increased significantly, compared with the control.