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-HBE[Ca2+]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。
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.