饱和氢盐水对心肌缺血再灌注损伤大鼠心肌细胞内质网应激的影响

Effects of hydrogen-rich saline on endoplasmic reticulum stress during myocardial ischemia-reperfusion in rats

目的 研究饱和氢盐水对大鼠心肌缺血再灌注损伤后心肌细胞内质网应激的影响.方法 选取健康成年清洁级雄性SD大鼠150只,采用随机数字表法将其分为5组（n=30）：空白对照组（Ⅰ组）、假手术组（Ⅱ组）、缺血再灌注组（Ⅲ组）、饱和氢盐水治疗组（Ⅳ组）、生理盐水治疗组（Ⅴ组）.Ⅰ组不做任何处理;Ⅱ组大鼠仅穿线不结扎;Ⅲ组制备大鼠心肌缺血再灌注损伤模型;Ⅳ组于再灌注前5 min给予1ml/100 g腹腔注射饱和氢生理盐水;Ⅴ组于再灌注前5 min给予1 ml/100 g腹腔注射等量生理盐水.于再灌注12、24 h后取左室心肌组织HE染色观察心肌病理学,同时采用原位末端转移酶标记法（TUNEL法）检测心肌细胞凋亡,蛋白质印迹法（Western blot）检测心肌细胞GRP78、Caspase-12、Bcl-2和Bax蛋白表达.结果 与Ⅰ组、Ⅱ组比较,Ⅲ组、Ⅳ组和Ⅴ组大鼠心肌缺血再灌注后心肌凋亡细胞增加,心肌细胞GRP78和Caspase-12表达水平升高,Bcl-2表达下调和Bax表达上调.与Ⅲ组、Ⅴ组比较,Ⅳ组大鼠心肌缺血再灌注后心肌凋亡细胞减少,心肌细胞GRP78和Caspase-12表达水平降低,Bcl-2表达上调和Bax表达下调.结论 饱和氢盐水可通过抑制内质网应激,降低细胞凋亡,减轻大鼠心肌缺血再灌注损伤,其机制可能与降低心肌细胞GRP78、Caspase-12和Bax蛋白表达,升高Bcl-2蛋白表达有关.

Objective To explore the effects of hydrogen-rich saline on endoplasmic reticulum stress during myocardial ischemia-reperfusion （I/R） in rats.Methods A total of 150 healthy male Sprague-Dawley rats were selected and then randomly divided into 5 groups of normal control （Ⅰ）,sham operation （Ⅱ）,myocardial ischemia-reperfusion （Ⅲ）,hydrogen-rich saline （Ⅳ） and normal saline （Ⅴ）（n =30 each）.Group Ⅰ had no treatment.In group Ⅱ,anterior descending branch was merely exposed but not ligated.Myocardial L/R was induced by an occlusion of anterior descending branch of left coronary artery for 30 min followed by 12 h and 24 h of reperfusion with bimbaum.Hydrogen-rich saline 1 ml/100 g was injected intraperitoneally 5 min before reperfusion in group Ⅳ.Normal saline 1 ml/100 g was injected intraperitoneally 5 min before reperfusion in group Ⅴ.The rats were sacrificed at 12 h and 24 h of reperfusion and heart tissues harvested.The pathological changes of myocardial tissue were detected by hematoxylin ＆ eosin staining.The apoptotic cardiomyocytes of myocardial tissue were tested by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling （TUNEL）.And the expressions of GRP78,Caspase-12,Bcl-2 and Bax in myocardial tissue were detected by Western blot.Results Compared with groups Ⅰ and Ⅱ,the numbers of apoptotic cardiomyocytes,the expression of GRP78,Caspase-12 and Bax in myocardial tissue significantly increased and the expression of Bcl-2 in myocardial tissue significantly decreased in groups Ⅲ,Ⅳ and Ⅴ.Compared with group Ⅲ and Ⅴ,the numbers of apoptotic cardiomyocytes,the expression of GRP78,Caspase-12 and Bax in myocardial tissue significantly decreased while the expression of Bcl-2 in myocardial tissue significantly increased in group Ⅳ.Conclusions Hydrogen-rich saline may decrease cell apoptosis and attenuate myocardial reperfusion injury through inhibiting endoplasmic reticulum stress.The mechanism may be associated with decreasing the expression of GRP78,Caspase-12 and Bax and increasing the expression of Bcl-2 in myocardial tissue.