摘要
目的探讨胰岛淀粉样多肽(IAPP,也称胰淀素Amylin)的纤维状态胰岛淀粉样纤维(IAf)对胰岛细胞膜的毒性作用及可能机制。方法比较用可溶性IAPP和IAf孵化培养的胰岛细胞膜流动性的变化,并在黏附细胞仪570记录各组[Ca2+]i的动态变化;以10μmol/LIAf组为对照组,分别比较Ca2+通道阻断剂组、无Ca2+培养液组、胆固醇干预组[Ca2+]i的动态变化,了解[Ca2+]i变化与钙离子通道的关系。结果细胞膜流动性和[Ca2+]i在IAf组中呈剂量依赖性升高,与可溶性IAPP组及空白对照组比较差异有统计学意义(P<0.01);而可溶性IAPP组与空白对照组间差异无统计学意义(P>0.05)。Ca2+通道阻断剂预处理组加10μmol/LIAf刺激后[Ca2+]i变化与对照组相比差异无统计学意义(P>0.05),而无Ca2+培养液组和胆固醇预处理组加10μmol/LIAf刺激后[Ca2+]i变化均明显低于对照组(P<0.01)。结论IAf可能通过改变胰岛细胞膜流动性和细胞内钙超载而导致细胞损伤,钙超载是由于外钙内流所致,其途径可能并非经过钙离子通道,可能与"淀粉样通道"形成有关。胆固醇具有拮抗此毒性的作用。
Obectives To investigate the toxicity effect of islet amyloid fibril （IAF） on cytomembrane of islet cells in vitro and possible mechanisms. Methods We incubated islet cells with soluble islet amyloid polypeptide （IAPP group） and IAF（IAF group） in concentration gradient, and blank control and stimulation control were set up. The membrane fluidity was detected by fluorescence polarization. The dynamic changes of [Ca^2＋ ]i were recorded by adherent cell analysis and sorting （ACAS）. The fluorescence intensity and time represented changes of [Ca^2＋ ]i. The 10μmol/L IAF as stimulation group was set up to compare other three groups, including Ca^2＋ channel blocker group, non-Ca^2＋ group and cholesterol intervention group. The changes of [Ca^2＋ ]i after adding 10μmol/L of IAF were recorded in these groups. Results Membrane fluidity and [Ca^2＋ ]i were positively dose-dependent in IAF group, and there was significant difference when compared with lAPP group and blank control group respectively （P〈0. 01）, while there was no significant difference between IAPP group and blank control group （P〉0. 05）. After adding 10 μmol/L of IAF, there was no significant difference in [Ca^2＋ ]i between Ca^2＋ channel blocker group and the control group （P〉0.05）, while [Ca^2＋ ]i was significantly lower in non-Ca^2＋ group and cholesterol intervention group （P〈0.01） than in control group. Conclusions IAF can change the membrane fluidity and lead to overloading of intra-cellular Ca^2＋. Extra-cellula Ca^2＋ enters cell, which results in the overloading of [Ca^2＋ ]i. It is not through Ca^2＋ channel but maybe through the ＂amyloid channel＂ by which extra-cellula Ca^2＋ enters cell. Cholesterol, one of the components of membrane, could counteract the effect of ＂amyloid channel＂.
出处
《中国糖尿病杂志》
CAS
CSCD
北大核心
2007年第7期429-432,共4页
Chinese Journal of Diabetes
