肌钙蛋白Ⅰ与肌红蛋白联合应用评价异丙肾上腺素诱导的心肌缺血损伤及凋亡发生

Serum cTnI and Mb as Markers for Evaluating Isoprenaline-induced Myocardial Ischemia and Apoptosis

目的:探讨肌钙蛋白Ⅰ与肌红蛋白在异丙肾上腺素诱导的心肌缺血中,对心肌损伤评价的价值。方法:将32只大鼠随机分成4组,用异丙肾上腺素建立不同程度的心肌缺血模型,分别为对照组和低、中、高剂量组,用ELISA方法检测不同程度心肌缺血大鼠血清中肌钙蛋白I含量与外周血肌红蛋白表达水平,同时结合心肌酶CK、CK-MB结果,分析血清中肌钙蛋白I检测的灵敏性,分析大鼠心肌缺血后外周血肌红蛋白与心肌缺血严重程度之间的关系。取大鼠心肌组织制成石蜡切片,采用末端标记法对其进行免疫组化染色,镜下观察心肌细胞是否凋亡及凋亡的程度与心肌缺血的关系,以凋亡细胞占细胞总数的平均百分比表示。结果:(1)大鼠模型建立成功,大鼠血清中肌钙蛋白Ⅰ含量明显升高,与CK、CK-MB的升高程度相比有显著差异(P<0.05),其升高的倍数均大于CK、CK-MB,且随着程度的加重,血清中肌钙蛋白Ⅰ蛋白的含量越高。(2)肌红蛋白在缺血早期升高较早且幅度较大,随缺血程度的进一步加重,其升高程度也随之增加。(3)心肌细胞凋亡检测可见,对照组未见明显凋亡细胞,低剂量组和中剂量组相继出现数量不等的棕黄色颗粒,而高剂量组出现大量棕黄色颗粒。结论:肌钙蛋白Ⅰ与肌红蛋白都可作为缺血心肌损伤程度评价的指标,肌钙蛋白Ⅰ具有较高的灵敏性并随缺血程度加深而升高。肌红蛋白在缺血发生的早期即可大幅升高,但对于缺血程度的评价价值不及肌钙蛋白Ⅰ。随着缺血程度的加深,心肌细胞除缺血坏死外还可出现凋亡,说明凋亡也是加重缺血表现的一个因素。

OBJECTIVE：To evaluate the values of cTnI and Mb in evaluating myocardial damage in isoprenaline-induced myocardial ischemia.METHODS：A total of 32 rats were established into models of myocardial ischemia of different degree using isoprenaline before being randomized to high-dose group,medium-dose group,low-dose group and control group.Serum cardiac troponin I（cTnI） and myoglobin（Mb） in peripheral blood measured by ELISA together with the levels of myocardial enzyme CK and CK-MB determined were used to analyze the sensitivity of cTnI detection in serum and the association between myoglobin in peripheral blood and the severity of myocardial ischemia.Paraffin section of mice＇s myocardium tissue was made,which were immunohistochemically stained by TUNEL method and microscopically observed regarding the cell apoptosis as well as the association between apoptotic degree and myocardial ischemia（expressed as the average percentage of apoptotic cells in the total）.RESULTS：1） The establishment of myocardial ischemia model in rats was successful.Serum content of cardiac troponin I（cTnI） increased significantly,showing significant differences as compared with the elevation degree of CK and CK-MB（P0.05）,and the elevation multiples were all higher than those of CK and CK-MB,furthermore,serum content of cTnI increased as the increase of the severity of myocardial ischemia;2） Serum Myoglobin（Mb） level witnessed a large increase at the early myocardial ischemia stage and the elevation increased further accompanied with the worsening of myocardial ischemia;3） Apoptosis of myocardial cells were noted in all except control group.Different amount of brown particles were noted in low-and medium-dose groups while a large number of brown particles were noted in large-dose group.CONCLUSION：Both cTnI and Mb all serve as evaluation markers for myocardial damage in myocardial ischemia.cTnI had a higher sensitivity and it elevated with the worsening of myocardial ischemia.Myoglobin level elevated significantly at the early stage of ischemia,but it has lower value as marker to evaluate the ischemia degree than does cTnI.With the worsening of ischemia,besides ischemic necrosis,apoptosis might occur in myocardial cells,suggesting that apoptosis is an important factor for the worsening of myocardial ischemia.