谷胱甘肽对胰岛素淀粉样纤维化的抑制作用

目的探索谷胱甘肽抑制胰岛素淀粉样纤维化及纤维细胞毒性的分子机制。方法在pH 2.0、37℃及90r·min-1震荡的条件下孵育胰岛素,采用硫黄素(ThT)荧光检测胰岛素形成淀粉样纤维的动力学曲线,8-苯胺-1-萘磺酸(ANS)荧光检测胰岛素分子聚集体表面疏水性的变化,透射电镜观察纤维形态,以淀粉样纤维诱导人红细胞的聚集为指标,评估谷胱甘肽对胰岛素纤维细胞毒性的抑制作用。结果胰岛素在本文的实验条件下孵育可形成淀粉样纤维,谷胱甘肽能够抑制胰岛素的淀粉样纤维化和降低形成的纤维聚集体的表面疏水性,并降低胰岛素纤维对细胞的损害作用。谷胱甘肽的这种作用与分子中的巯基相关。结论谷胱甘肽能够抑制胰岛素的淀粉样纤维化,改变胰岛素聚集体的表面特性,从而使聚集体的细胞毒性降低。

Inhibitory effect of glutathione on insulin amyloid fibrillation

Objective To investigate the inhibitory effect of glutathione （GSH） on amyloid fibrillation and fibrillar cytotoxicity of in-sulin .Methods Insulin fibrils were prepared by incubating the protein at pH 2 .0 and 37 ℃ with agitation （90 r ？ min - 1 ） .Fibril formation was monitored by thioflavine T fluorescence and the surficial hydrophobicity of insulin aggregates was probed by ANS fluorescence .The fibrillar morphology was visualized under transmission electron microscopy and the cytotoxicity of insulin fibril was evaluated by measuring the aggregation of human red blood cells .Results Incubation of insulin under the condition of the present study resulted in the formation of amyloid fibril .The growth kinetics ,surfacial hydrophobicity and morphology of the fi-bril were changed by co-incubating insulin and GSH .GSH inhibited the amyloid formation of insulin in a dose-dependent manner . Moreover , GSH decreased the fibrillar hydrophobicity and abolished the cell damages induced by insulin aggregates . Conclusion GSH is able to inhibit amyloid formation of insulin and to decrease the fibril-induced cytotoxicity .It is suggested that the anti-amyloidogenic role of GSH is attributed to the thiol group of the molecule .