K^+通道阻断剂四乙铵对胰岛β-细胞凋亡的作用机制研究  

Effects of tetraethylammonium on the apoptosis of pancreatic β-cells

作　　者：虞涛[1] 雷萍[2] 朱慧芬[2] 邵静芳[2] 杨敬[2] 张悦[2] 沈关心[2] 

机构地区：[1]华中科技大学同济医学院附属妇女儿童保健中心检验部,武汉430016 [2]华中科技大学同济医学院免疫学系,武汉430030

出　　处：《免疫学杂志》2006年第4期358-361,共4页Immunological Journal

基　　金：国家"973"重点基础研究发展规划(CB510008);国家自然科学基金(30300166)资助项目

摘　　要：目的研究K+通道阻断剂四乙铵(TEA)对诱导胰岛β细胞凋亡的作用及机制。方法以IFNγ+IL1β诱导NIT细胞凋亡,同时加入TEA,通过AnnexinV检测、PI染色,利用四唑蓝比色实验(MTT法)检测不同浓度TEA对链脲佐菌素(STZ)处理细胞活性的影响;使用流式细胞术检测TEA对诱导NIT细胞凋亡的影响;通过硝酸还原酶法、硫代巴比妥酸TBA法、化学比色法、黄嘌呤氧化酶法、分别测定培养上清液中NO和氧自由基含量以及细胞裂解物中NO合成酶(NOS)及超氧化物歧化酶(superoxidedismutase,SOD)活性。结果1mmolLTEA能显著抑制IFNγ+IL1β诱导的NIT细胞凋亡。IFNγ+IL1β可显著增加NOS活性,降低SOD的活性,从而导致培养上清液中NO及氧自由基的含量显著增加;TEA可显著抑制STZ的作用。结论K+通道在胰岛β细胞的凋亡中可能起着重要作用;K+通道阻断剂TEA可显著抑制IFNγ+IL1β诱导的胰岛β细胞凋亡,其机制可能与下调NIT细胞诱导性NO合成酶(iNOS)活性,上调SOD活性,减少NO的产生以及增强其清除氧自由基的能力有关。Objective To examine the effects of tetraethylammonium （TEA, K^＋ channels blocker） on pancreatic β-cell apoptosis and explore its mechanism. Methods Mouse β-cells （NIT cells） were exposed to IFN-γ plus IL-1β to induce the apoptosis. TEA was applied along with apoptotic inducers to prevent efllux of intracellular K^＋ , and then the cells were stained with Annexin V and PI. The percent of apoptotic or viable cells was determined by flow cytometry （FCM）. MTr method was used to observe the effects of different concentrations of TEA on the activity of apoptotic NIT cells. Nitrate reductase method, thiobarbituric acid （TBA）, chemical colorimeter, and xanthine oxidase method were used to quantify the contents of NO and ROS produced by NIT-cells and to detect the activity of iNOS （ inducible nitric oxide synthase） as well as super oxide dismutase （SOD） in cells lysates. Results TEA （1 mmol/L） could significantly inhibit the NIT cell apoptosis induced by IFN-γ plus IL-1β （P 〈 0.01）. TEA also could inhibit the upregulafion of iNOS activity and the downregulation of SOD activity in cytoplasm of NIT cells induced by IFN-γ plus IL-1β, hence prevented productions of NO （ P 〈 0.01） and ROS （ P 〈 0.01）; Conclusion K^＋ channel blocker TEA may inhibit the apoptosis of pancreatic β-cells significantly, which may relate to inhibition of enzyme activity change induced by IFN-γ plus IL-1β, such as the activity of iNOS and SOD. K^＋ channels may play an important role in the apoptosis of pancreatic β-cells.

关 键 词：K^+通道 胰岛Β细胞 K^+通道阻断剂 细胞凋亡 

分 类 号：R965[医药卫生—药理学]