淫羊藿苷通过下调ATF6-DR5信号通路改善异丙肾上腺素所致小鼠左心室心肌细胞凋亡

Icariin improves ISO-induced left ventricle cardiomyocyte apoptosis via downregulating ATF6-DR5 signaling pathway in mice

目的以C57BL/6(简称C57)小鼠为研究对象,并基于ATF6-DR5信号通路研究淫羊藿苷(icariin,ICA)对异丙肾上腺素(isoproterenol,ISO)诱导的左心室心肌细胞凋亡作用及机制。方法30只6~7周龄的雄性C57小鼠连续14 d经颈背部皮下注射ISO(5 mg·kg^-1·d^-1)诱导心肌细胞凋亡,10只C57小鼠注射等体积生理盐水作为对照组。注射ISO的小鼠随机分为3组(n=10):ISO组、ICA-L组和ICA-H组。ICA组分别灌胃给予ICA混悬液(15,60 mg·kg^-1·d^-1),连续14 d。Control组和ISO组灌胃均给予等体积双蒸水。末次给药结束后称全心重,分离左心室(含室间隔)称重,计算左心室质量指数。TUNEL染色检测左心室心肌细胞凋亡情况;Western blot检测左心室GRP78、ATF6和DR5的蛋白水平。结果与Control组相比,ISO组左心室质量指数明显升高(P<0.05);TUNEL染色结果发现,左心室心肌细胞凋亡率明显增加(P<0.05);Western blot结果发现,左心室GRP78、ATF6和DR5的蛋白水平明显升高(P<0.05)。与ISO组相比,ICA高剂量组左心室质量指数明显降低(P<0.05);左心室心肌细胞凋亡率明显降低(P<0.05);左心室GRP78、ATF6和DR5的蛋白水平明显降低(P<0.05)。结论ICA具有改善ISO所致的左心室心肌细胞凋亡作用,其机制可能与抑制ATF6-DR5信号通路有关。

Aim To research the effect of icariin(ICA)on isoproterenol-induced left ventricular cardiomyocyte apoptosis in C57 mice based on the ATF6-DR5 signaling pathway and the related mechanism.Methods Thirty male C57 mice of 6~7 weeks were subcutaneously with ISO(5 mg·kg^-1·d^-1)to induce the cardiomyocyte apoptosis model of mice for 14 day,and 10 male C57 mice of 6~7 weeks were subcutaneously with normal saline for control group.The mice injected with ISO were randomly divided into three groups(n=10):ISO group,ICA-L group and ICA-H group.The ICA group were intragastrically administered of ICA(15,60 mg·kg^-1·d^-1)respectively for 14 days.The control group and ISO group were intragastrically administered of double-distilled water.After the last administration,the total heart weight and the left ventricle(including ventricular septum)were weighed separately,and the left ventricular mass index was calculated.Cardiomyocyte apoptosis of left ventricular was observed by TUNEL staining;the protein levels of GRP78,ATF-6 and DR5 were examined by Western blot.Results Compared with control group,the left ventricular mass index increased significantly(P<0.05)and the results of TUNEL staining showed that myocardial apoptosis of left ventricular increased significantly(P<0.05),and the results of Western blot showed that the protein levels of GRP78,ATF6 and DR5 increased markedly(P<0.05)in ISO group.Compared with ISO group,the left ventricular mass index and the myocardial apoptosis of left ventricular were reduced significantly(P<0.05),and the protein levels of GRP78,ATF6 and DR5 were reduced significantly(P<0.05)in ICA high-dose group.Conclusions ICA can improve the left ventricular cardiomyocyte apoptosis in ISO-induced mice,and its mechanism may be related to the inhibition of ATF6-DR5 signaling pathway.