Aβ25-35诱导大鼠心肌细胞内质网应激和细胞凋亡的研究

Aβ25-35 induce endoplasmic reticulum stress and apoptosis of rat cardiomyocytes

目的 研究β淀粉样蛋白25-35（Aβ25-35）对培养大鼠心肌细胞的凋亡及内质网应激相关蛋白的影响,探讨内质网应激在A β25-35所致心肌损伤中的作用.方法 体外培养大鼠心肌细胞,给予不同浓度Aβ25-35刺激,用MTT方法观察心肌细胞的存活率,采用Hoechst33258染色观察心肌细胞的形态,流式细胞术检查细胞凋亡率,采用Western blot方法检测内质网应激蛋白X盒结合蛋白-1（XBP-1）、葡萄糖调节蛋白78 （GRP78）和CCAAT/增强子结合蛋白同源蛋白（CHOP）的水平,以及凋亡蛋白cleaved caspase-3和cleaved PARP的水平.结果 Aβ25-35可以降低体外培养大鼠心肌细胞的存活率,促进凋亡,且呈现浓度依赖的方式.给予Aβ25-35后内质网应激蛋白XBP-1、GRP78和CHOP表达增加,同时凋亡蛋白cleaved caspase-3和cleaved聚腺苷二磷酸核糖聚合酶（PARP）表达也增加.结论 Aβ25-35可以导致体外培养的大鼠心肌细胞发生凋亡,而内质网应激可能参与了心肌细胞发生凋亡过程,为有效防治AD相关性心肌损伤提供新思路.

Objective To investigate the effects of amyloid-β （Aβ）25-35 on endoplasmic reticulum （ER） stress and apoptosis in cultured rat cardiomocytes,and to elucidate the role of ER stress in the injury of cardiomocytes induced by Aβ25-35.Methods The isolated rat myocardial cells were cultured in vitro.Following stimulation of Aβ25-35 with different dose,the survival ratio was observed with methyl thiazolyl tetrazolium （MTT） method.Hoechst33258 staining was used to observe the morphology of apoptotic changes.The percentage of apoptotic cardiomyocytes was quantified with flow cytometry.The expressions of ER stree proteins,including X box-binding protein-1 （XBP-1）,glucose-regulated protein 78 （GRP78）,and CCAAT/enhancer-binding protein homologous protein （CHOP） were measured with Western blot.The cleaved caspase-3 and cleaved poly （ADP-ribose） polymerase （PARP） were measured with Western blot.Results Aβ25-35 decreased the survival ratio and induced the apoptosis of cultured rat cardiomocytes in dose-dependent mode.Meanwhile,Aβ25-35 increased the expressions of ER stree proteins,including XBP-1,GRP78,and CHOP.Aβ25-35 increased the expressions of cleaved caspase-3 and cleaved PARP.Conclusions Aβ25-35 could induce the apoptosis of rat cardiomyocytes,which were involved in ER stress possibly.This study might provide a new strategy for clinical treatment of Alzheimer＆#39;s disease （AD）-associated myocardial injury.