可溶性生长刺激表达基因2蛋白对缺血性心肌病大鼠心室重塑的调控作用

Regulatory effect of soluble growth stimulator gene 2 protein on ventricular remodeling in rats with ischemic cardiomyopathy

目的探讨可溶性生长刺激表达基因2蛋白(sST2)对缺血性心肌病(ICM)大鼠心室重塑的调控作用。方法采用左侧冠状动脉结扎法建立ICM大鼠模型,随机分为模型组(15只)、空载体组(15只)及用药组(15只),另设假手术组(15只);空载体组皮下注射1 mL空载腺病毒,用药组皮下注射1mL腺病毒sST2载体诱导sST2过表达,模型组及假手术组皮下注射等量生理盐水,所有大鼠连续给药2 d后正常饲养1周。所有大鼠均在末次给药后1周通过超声心动图检查心室重塑指标[左心室射血分数(LVEF)、左心室舒张末期内径(LVEDd)、左心室收缩末期内径(LVESd)、室间隔舒张末期厚度(IVSd)],并检测血清sST2、心肌损伤标志物[心肌肌钙蛋白I(cTnI)、肌酸激酶(CK)、肌酸激酶同工酶(CK-MB)]及炎症指标[白细胞介素(IL)-33、IL-6、肿瘤坏死因子-α(TNF-α)]水平,同时通过苏木精-伊红(HE)染色实验与Masson染色实验观察大鼠心肌组织病理变化及心肌纤维化程度,并通过免疫组化实验检测心肌组织中sST2表达情况。sST2表达水平与炎症指标及心室重塑指标的相关性应用Pearson相关性分析。结果与假手术组相比,模型组及空载体组大鼠心肌细胞排列紊乱,细胞间隙较大,心肌细胞间质胶原沉积较为明显,用药组大鼠心肌细胞排列更加不规则,细胞间隙更大,间质胶原沉积更多。模型组、空载体组及用药组LVEF、IL-33低于假手术组,且用药组上述指标低于模型组与空载体组(F=618.974、28.151,P<0.05);模型组、空载体组及用药组LVEDd、LVESd、IVSd、sST2、cTnI、CK、CK-MB、IL-6、TNF-α水平高于假手术组,且用药组上述指标高于模型组与空载体组(F=3.665、3.418、122.807、36.596、101.736、37.573、79.716、20.371、51.494,P<0.05);模型组、空载体组及用药组心肌组织中sST2表达水平高于假手术组,且用药组高于模型组与空载体组(F=122.843,P<0.05);ICM大鼠血清及心肌组织中sST2水平与心室重塑指标LVEF及炎症指标IL-33呈负相关(P<0.05),与LVEDd、LVESd、IVSd、IL-6、TNF-α呈正相关(P<0.05)。结论sST2与ICM大鼠心室重塑有关,sST2高表达会促进大鼠心室重塑进程。

Objective To explore the regulatory effect of soluble growth stimulator gene 2 protein(sST2)on ventricular remodeling in rats with ischemic cardiomyopathy(ICM).Methods The left coronary artery ligation method was used to establish the ICM rats model.Rats were randomly divided into model group(15 cases),empty vector group(15 cases)and drug group(15 cases).A sham operation group(15 cases)was set up.The empty vector group was subcutaneously injected with 1 mL of empty adenovirus.The drug group was subcutaneously injected with 1 mL adenovirus carrying sST2 vector to induce the overexpression of sST2.The model group and the sham operation group were subcutaneously injected with equal amount of normal saline.All rats fed normally for 1 week after continuous administration for 2 days.All rats were examined by echocardiography for ventricular remodeling indexes[left ventricular ejection fraction(LVEF),left ventricular end-diastolic diameter(LVEDd),left ventricular end-systolic diameter(LVESd),interventricular septal thickness at diastole(IVSd)]one week after the last administration.The levels of serum sST2,myocardial injury markers[cardiac troponin I(cTnI),creatine kinase(CK),creatine kinase isoenzyme(CK-MB)]and inflammatory indicators[interleukin(IL)-33,IL-6,tumor necrosis factorα(TNF-α)]were detected.At the same time,the pathological changes of rat myocardial tissue and the degree of myocardial fibrosis were observed by hematoxylin-eosin(HE)staining and Masson staining.The expression of sST2 in myocardial tissue was detected by immunohistochemistry.Pearson correlation was used to analyze the correlation between sST2 expression level,inflammatory indicators and ventricular remodeling indicators.Results Compared with the sham operation group,the myocardial cells in the model group and empty vector group were arranged in disorder,with larger intercellular space and more obvious interstitial collagen deposition,and the myocardial cells in the drug group were arranged more irregularly,with larger intercellular space and more interstitial collagen deposition.LVEF and IL-33 in the model group,empty vector group,and drug group were lower than those in the sham operation group,and the above indexes in the drug group were lower than those in the model group and empty vector group(F=618.974,28.151;P<0.05).The levels of LVEDd,LVESd,IVSd,sST2,cTnI,CK,CK-MB,IL-6,and TNF-αin the model group,empty vector group,and drug group were higher than those in the sham operation group,and the above indexes in the drug group were higher than those in the model group and empty vector group(F=3.665,3.418,122.807,36.596,101.736,37.573,79.716,20.371,51.494;P<0.05).The expression level of sST2 in myocardial tissue of the model group,empty vector group,and drug group was higher than that of the sham operation group,and the sST2 expression level in the drug group was higher than that in the model group and empty vector group(F=122.843,P<0.05).The level of sST2 in serum and myocardial tissue of ICM rats was negatively correlated with ventricular remodeling index LVEF and inflammatory index IL-33(P<0.05),but positively correlated with LVEDd,LVESd,IVSd,IL-6,and TNF-α(P<0.05).Conclusion sST2 is associated with ventricular remodeling in ICM rats,and high expression of sST2 promotes the process of ventricular remodeling in rats.