紫绀型先天性心脏病心肌线粒体DNA拷贝数的变化

Changes of mitochondrial DNA copy in congenital heart disease with cyanosis

目的比较紫绀型和非紫绀型先天性心脏病心肌线粒体DNA(mtDNA)拷贝数,探讨慢性缺氧状态下心肌线粒体的适应性改变。方法选取紫绀型和非紫绀型先天性心脏病各10例,取手术中切除的右室流出道心肌组织,运用实时荧光PCR技术检测心肌组织中mtDNA相对拷贝数,运用实时荧光RT-PCR技术检测心肌组织中线粒体转录因子A(Tfam)的mRNA表达水平。结果紫绀型先心病患者右室流出道心肌组织中mtDNA相对拷贝数明显高于非紫绀组(P<0.01),Tfam的mRNA表达水平明显高于非紫绀组(P<0.01)。结论紫绀型先天性心脏病患者右室流出道心肌mtDNA复制增多,可能为心肌在慢性缺氧状态下的代偿性改变。

Objective To compare mitochondrial DNA copy in congenital heart disease with and without cyanosis, discuss mitochondrial response to chronic hypoxia in myocardium. Methods 20 patients with cyanotic （n= 10） or acyanotic cardiac defects （n = 10） were investigated. Myocardium from the right ventricular outflow tract were studied, mtDNA copy was detected by RT-PCR. Mitochondrial transcription factor A （Tram） mRNA was detected by RT-PCR. Results mtDNA copy was significantly elevated in patients with cyanotic compared to that with acyanotic congenital heart disease （P〈0.01）. mRNA levels of Tram were significantly higher in the myocardium of cyanotic than that of acyanotic patients （P〈0.01）. Conclusions mtDNA replication is activated in myocorrdium in right ventricular outflow tract in congenital heart disease with cyanosis, which could he the adaptive response to chronic hypoxia.