33 Hz脉冲电场辐照对胰岛素淀粉样变性的影响

蛋白质结构失稳后会发生错误折叠、集聚或纤维化，不仅丧失正常功能，有时甚至会产生生物毒性，导致相关疾病。纤维化了的蛋白质是神经退行性疾病以及二型糖尿病等的主要诱因，它在溶液中具有和淀粉类似的特性，因此蛋白质的纤维化又被称为淀粉样变性。电磁辐射是引起蛋白质结构失稳的一个常见因素。经电场辐照后，蛋白质会发生去折叠和集聚，改变自发折叠机制。同时，经受电场辐照的扰动而失稳的蛋白质，纤维化过程也会受到一定的影响。以胰岛素为研究对象，利用硫磺素T(ThT)染色的荧光光谱法、透射电子显微镜(TEM)以及圆二色谱(CD)法，分别从纤维化的宏观动力学过程、成熟纤维丝微观形貌以及原纤维二级结构组成等不同角度，探究经33 Hz脉冲电场(PEF)不同电场强度及不同持续时间辐照后蛋白质在体外淀粉样变性机制的变化情况。结果表明，胰岛素溶液经过33 Hz PEF辐照后，淀粉样变性初期产生前体蛋白的成核期延长，原纤维丝聚集延长过程(即中间产物的寿命)缩短，形成的成熟纤维丝长度变短且整齐成簇无分支。这些效应随着辐照电场强度和辐照时间的增加而有不同程度的加强。研究结果一致说明PEF辐照对胰岛素的淀粉样变性有一定的抑制作用。

Effect of 33 Hz Pulsed Electric Field on Insulin Amyloidosis

The destabilizing of protein leads to self‐aggregation and fibrillar assemblies .In the form of amyloid fibrils or fibril precursors ,protein not only lacks the original biological function but also may be harmful to organisms .Stimulated by an intense electric field ,the secondary structures of protein can be disturbed and transfer to aggregations or unfolding conformations ,which may inhibit the fibrillation process .As a model for disease‐associated amyloids ,insulin fibrillation is proposed to occur via partial unfolding of a monomeric intermediate .This project is focusing on in‐vitro studies employing a 33 Hz pulsed electric field (PEF) to see if there is possible causal connection between insulin fibrillation and PEF exposure .Thioflavin T (ThT)‐fluorescence ,cir‐cular dichroism(CD) and transmission electron microscopy (TEM ) techniques were employed regarding the effects of exposure duration and field intensity of the PEF on the fibrillation mechanism of insulin .The results confirm that the PEF exposed insulin molecules may primitively have a slight change in its native structure ,causing aggregation .The aggregates in the PEF exposed insulin solution are difficult to dissolve to facilitate the unfolding of insulin molecules .When the molecular conformation converts from α‐helical toβ‐sheet structure ,the fibrillation velocity in the PEF exposed insulin is accelerated by the PEF exposure thereby shortening the lifetime of the intermediates .The morphology of mature fibrils changes from long twisted fibrils to shorter and less matured fibrils .All these effects enhance when the exposure duration and electric intensity increase .The investigated evi‐dences suggest that the PEF can inhibit insulin amyloidosis .