心力衰竭大鼠心肌细胞端粒酶逆转录酶的表达

Expression of telomerase reverse transcriptase in myocardial cell of rats with heart failure

目的研究异丙肾上腺素(ISO)诱导的心力衰竭大鼠心肌细胞端粒酶逆转录酶(TERT)的表达意义。方法健康清洁级SD大鼠20只,随机分为对照组及心力衰竭模型组(ISO组)各10只,对照组腹腔注射生理盐水2 mL.kg-1,ISO组腹腔注射ISO30 mg.kg-1,均每日1次,连续2 d,给药结束观察48 h。检测大鼠血清肌酸激酶(CK)、乳酸脱氢酶(LDH)水平,计算心脏系数,同时检测心肌细胞超氧化物歧化酶(SOD)活性和丙二醛(MDA)水平;应用Western blotting方法检测TERT蛋白表达的变化;利用免疫组织化学方法检测TERT蛋白在心肌细胞中的定位。结果与对照组比较,ISO组大鼠血清CK、LDH明显升高(P<0.01),心肌坏死程度加重,心脏系数也显著增加(P<0.01);ISO组大鼠心肌细胞MDA明显升高(P<0.05),SOD活性显著下降(P<0.01);对照组心肌细胞未见TERT蛋白表达,ISO组大鼠心肌细胞TERT蛋白表达明显增加,免疫组织化学实验结果显示ISO组大鼠心肌细胞浆中和胞核内有TERT阳性免疫产物生成。结论心力衰竭大鼠心脏存在心肌细胞增殖,心肌细胞增殖对心功能有代偿作用。

Objective To research the expression of telomerase reverse transcriptase （TERT） in myocardial cell of rats with heart failure induced by isoprenaline（ISO）. Methods Twenty healthy rats were randomly divided into control group and heart failure model group（ ISO group）. The rats in control group were given normal saline（2 mL · kg^-1 ） by intraperitoneal injection,and ISO（30 mg · kg^-1） was used in ISO group,once a day,for 2 days. serum creatine kinase（CK） ,lactate dehydrogenase （LDH） , cardiac index, superoxide dismutase （SOD） activity and malondialdehyde （MDA） were detected. TERT protein was determined by Western blotting, and the localization of TERT in myocardial cell was determined by immunohistocheminstry. Results Compared with control group, CK, LDH and cardiac index were higher（ P 〈 0.01 ） ,the degree of heart muscle necrosis aggravated. The contents of MDA in myocardial cell increased obviously （P 〈 0.05 ） , the activity of SOD descended significantly. The TERT expression of myocardial cell was not obversed in control group, but the expression increased obviously in ISO group. Positive immunohistochemical staining of TERT was located in the nucleus and cytoplasm of myocardial cell in ISO group. Conclusion There is myocyte proliferation in the rats with heart failure. Myocyte proliferation play compensatory role in heart function.