线粒体DNA拷贝量降低诱发人支气管上皮细胞钙信号失调

采用溴化乙锭（EtBr）诱导线粒体DNA（mitochondrial DNA，mtDNA）拷贝量降低的人支气管上皮细胞株（ρ-HBE）；Real—timePCR与共聚焦成像表明，经EtBr诱导60d并挑取的单克隆细胞株，其mtDNA拷贝量下降为正常细胞的24％，成功构建了ρ-HBE。与母本细胞相比，ρ-HBE群体倍增时间延长，生长速度减慢。流式细胞术检测细胞线粒体膜电位（△ψm）下降，以Fura-2标记胞浆内游离钙，ρ-HBECa2＋]i升高；线粒体解耦联剂FccP刺激细胞后，激光共聚焦扫描显微镜动态监测单个活细胞Ca2＋]i变化，发现ca2＋]i水平波动幅度小。提示mtDNA拷贝数降低可导致细胞内钙信号调节紊乱。

The Effects of Mitochondrial DNA Depletion in Human Bronchial Epithelial Line on Calcium Homeostasis

Human bronchial epithelial cells （HBE cells） were cultured in culture medium containing ethidi- urn bromide （EtBr） to establish a mitochondrial DNA （mtDNA）-depleted HBE model （ρ HBE）. Real-time PCR and confocal imaging show that the content of mtDNA in p-HBE selected from limiting-dilution in EtBr-treated cells was 24% of the wide-type HBE. Compared with parent HBE, p- HBE showed a slower growth rate, increased level of intracellular Ca2＋ concentrations （Ca2＋]i）, decreased condition of mitochondrial transmembrane potential （Aψm）, the magnitude of elevation of Ca2＋]i was markedly reduced to FCCP stimulation. These results indicated that the depletion of mtDNA disrupted calcium homeostasis.