Objective To investigate the expressions of thyroid transcription factor-1 (TTF-1), the type Ⅱ alveolar epithelial cells (AECII)-specific marker, and vimentin, the fibroblast-specific marker, in the lungs of neonatal mice with bronchopulmonary dysplasia (BPD) and explore the pathogenesis of BFD. Methods Neonatal mice were exposed to hyperoxia to induce BPD, and pathological changes in the lung tissues were examined. At 3, 7,14 and 21 days after the exposure, the protein and mRNA expressions of TTF-1 and vimentin were detected by double-labeled immunofluorescence assay and real-time PCR, respectively. Results Compared with the neonatal mice exposed in normal air, those with hyperoxic exposure showed developmental disorders and collagen deposition in the lung tissues. The protein expression of TTF-1 decreased while vimentin expression increased in the lung tissues, where their co-expression was observed at 14 and 21 days after the exposure. TTF-1 mRNA expression decreased markedly (P<0.05) and vimentin mRNA increased significantly in the lung tissues at 21 days after hyperoxic exposure of the mice (P<0.05). Conclusion Hyperoxia-induced transition of AECH to fibroblasts may play an important role in pulmonary fibrosis in neonatal mice with BPD.%目的 观察高氧暴露新生鼠肺泡Ⅱ型细胞(AECⅡ)标记[甲状腺转录因子,(TTF-1)]及成纤维细胞标记[波形蛋白,( Vimentin)]的表达规律,探讨支气管肺发育不良(BPD)发病机制.方法 新生小鼠随机分为:对照组及BPD组,高浓度氧暴露制作BPD小鼠模型,观察肺组织病理变化,于实验后3、7、14、21 d应用免疫荧光双标及荧光定量PCR技术检测TTF-1及Vimentin蛋白、mRNA的表达情况.结果 与对照组比较,BPD组高氧暴露后小鼠肺组织逐渐出现肺泡发育障碍、胶原沉积明显；AECⅡ标记TTF-1表达逐渐减弱,成纤维细胞标记Vimentin表达逐渐增强,14、21d时两者可见明显的共表达；BPD组21 d TTF-1mRNA表达较同时间对照组下调(P＜0.05),而Vimentin mRNA表达较同时间对照组上凋(P＜0.05).结论 高氧致AECⅡ向成纤维细胞转化可能是BPD纤维化的重要机制.
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