间歇性缺氧预适应通过提高细胞膜修复能力减轻心肌缺血/再灌注损伤

Intermittent hypoxic adaptation attenuates myocardial ischemia/reperfusion injury by improving ability of plasma membrane repair

目的探究间歇性低氧预适应(intermittent hypoxia adaptation,IHA)能否通过增强细胞膜修复能力,从而减轻心肌缺血/再灌注(ischemia/reperfusion,I/R)损伤。方法利用小动物低压舱模拟高空缺氧环境建立低氧预适应模型,将雄性Sprague-Dawley大鼠随机分为4组,分别为:假手术(Sham)组、假手术+预适应(Sham+IHA)组、缺血/再灌注手术(I/R)组和缺血/再灌注手术+预适应(I/R+IHA)组。预适应7 d后Sham组仅进行开胸手术,冠状动脉左前降支(left anterior descending artery,LAD)挂线不结扎,I/R组结扎LAD 30 min后再灌注12 h。造模成功后对各组大鼠行超声心动图检查,评估心脏结构与功能,以酶联免疫吸附(enzyme linked immunosorbent assay,ELISA)法检测血清乳酸脱氢酶同工酶-1(lactate dehydrogenase isoenzyme-1,LDH-1)、肌酸激酶同工酶-MB(creatine kinase isoenzyme-MB,CK-MB)水平,处死大鼠后苏木素-伊红(hematoxylin-eosin staining,HE)染色观察心肌组织病理变化,免疫荧光法检测心肌组织内MG-53荧光强度,Western blot测定心肌组织MG-53、dysferlin、caveolin-3表达水平。结果与I/R组相比,I/R+IHA组心肌组织损伤较轻,超声心动图检测各项收缩功能指标均明显升高(P<0.01),提示IHA处理能明显改善心脏收缩功能。与I/R组相比,I/R+IHA组大鼠心肌MG-53荧光强度明显增加(P<0.05),dysfelin、MG-53、caveolin-3蛋白表达含量均显著升高(P<0.05)。结论IHA处理产生的作用包括降低血清LDH浓度、改善心肌病理学改变、提高心脏收缩功能减轻大鼠心肌I/R损伤,其机制可能与提高细胞膜修复能力有关。

AIM To investigate whether intermittent hypoxic adaptation(IHA)can attenuate myocardial ischemia/reperfusion(I/R)injury by improving the ability of plasma membrane repair.METHODS Small animal hypobaric chamber was used to simulate different barometric heights.Male Sprague Dawley rats were randomly divided into four groups:Sham,Sham+IHA,I/R,I/R+IHA.After 7 days of IHA,different treatments were used in each group.In I/R group,LAD was ligated for 30 minutes and then reperfusion for 12 hours.The myocardial ischemia/reperfusion injury was assessed with HE staining,echocardiography.The fluorescence intensity of mg-53 in myocardial tissue was detected by immunofluorescence assay.The levels of serum lactate dehydrogenase isoenzyme-1(LDH-1)and creatine kinase isoenzyme-MB(CK-MB)were detected by enzyme-linked immunosorbent assay(ELISA).The expression of dysferlin,caveolin-3 and MG-53 proteinwere detected by Western Blot.RESULTS There was no significant difference in all indexes between Sham and Sham+IHA.Compared with those in I/R group,the myocardial injury in I/R+IHA group was lighter,and the systolic function were significantly increased(P<0.01).Compared with those in IR group,the fluorescence intensity of MG-53 in I/R+IHA group was significantly increased(P<0.05),and the expression levels of dysfelin,MG-53 and caveolin-3 protein were significantly increased(P<0.05).CONCLUSION IHA treatment can reduce myocardial I/R injury by improving the ability of plasma membrane repair in adult SD rats.