本文選題：亞砷酸鈉 + 大鼠胰島β細胞　； 參考：《大連醫(yī)科大學》2013年碩士論文

【摘要】：目的:砷（As）是一種廣泛存在于地殼中的類金屬元素，主要以有機砷和無機砷兩種形式存在，其中無機砷的毒性更強。人類接觸砷最主要的途徑是環(huán)境暴露，如接觸被砷污染的水源。近年有研究顯示，長期居住在富砷地區(qū)的人群糖尿病高發(fā)，提示砷可能對胰島細胞具有毒性作用。有研究證實砷可引起胰島細胞凋亡和DNA損傷。但關于砷對胰島細胞癌基因和抑癌基因表達及其編碼的蛋白質(zhì)的影響尚不明確。本研究探討了砷對胰島細胞p53、mdm2和Kras等基因和蛋白表達的影響。 方法：選定大鼠胰島β細胞（INS-1）。用MTT法檢測亞砷酸鈉對INS-1的毒性作用。用熒光實時定量PCR法檢測亞砷酸鈉對大鼠胰島β細胞野生型p53（Tp53）、mdm2和Kras基因表達的影響。用Western blot免疫印跡檢測亞砷酸鈉對大鼠胰島β細胞內(nèi)突變型p53蛋白和mdm2蛋白表達的影響。 結果：（1）亞砷酸鈉對大鼠胰島細胞的毒性作用：亞砷酸鈉（0、2.5、5、10、20、40、80、160μM）在37℃條件下，分別作用于INS-1細胞48h和72h后， OD值隨濃度的遞增而降低，，細胞存活率隨著亞砷酸鈉劑量的增大而降低，計算IC50分別為5.66μM、2.78μM；（2）亞砷酸鈉對大鼠胰島細胞Tp53、mdm2和Kras基因表達的影響：48h染毒各組Tp53（野生型p53腫瘤抑制基因）表達呈下降趨勢， mdm2、Kras基因表達增高；72h染毒中、低劑量組Tp53腫瘤抑制基因表達下降更加明顯，中、高劑量組Kras基因表達率升高更加明顯；（3）亞砷酸鈉對大鼠胰島細胞突變型p53蛋白和mdm2蛋白質(zhì)表達的影響：48h染毒后中、高劑量組突變型p53蛋白表達明顯增加，低劑量組突變型p53蛋白表達無明顯變化；72h染毒各組突變型p53蛋白表達均增加；而48h染毒和72h染毒均為中、高劑量組mdm2蛋白表達增加；72h染毒組與48h染毒組相比，中、高劑量染毒的p53蛋白表達量增加的差別顯著。 結論：亞砷酸鈉作用于INS-1可造成細胞內(nèi)抑癌基因Tp53表達率降低，且致癌基因mdm2和Kras的表達率增加；砷可導致INS-1細胞Tp53向突變型p53的轉變。
[Abstract]:Objective: as is a kind of metalloid element in the crust, which mainly exists in organic arsenic and inorganic arsenic, among which inorganic arsenic is more toxic. The main route of human exposure to arsenic is environmental exposure, such as exposure to water contaminated by arsenic. Recent studies have shown that there is a high incidence of diabetes in people living in arsenic-rich areas for a long time, suggesting that arsenic may have toxic effects on islet cells. Studies have shown that arsenic can induce apoptosis and DNA damage in islet cells. However, the effects of arsenic on the expression of oncogenes and tumor suppressor genes in islet cells and the proteins encoded by them are unclear. In this study, we investigated the effects of arsenic on the expression of p53 mdm2 and Kras genes and proteins in islet cells. Methods: rat islet 尾 cells were selected. The toxicity of sodium arsenite to INS-1 was detected by MTT method. The effect of sodium arsenite on the expression of wild-type p53Tp53mdm2 and Kras in rat islet 尾 cells was detected by real-time fluorescence quantitative PCR. The effect of sodium arsenite on the expression of mutant p53 and mdm2 protein in rat islet 尾 cells was detected by Western blot Western blot. Results the toxic effect of sodium arsenite on islet cells of rats: sodium arsenite at 37 鈩

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