目的 探究Brahma相关基因1（Brahma-related gene 1, Brg1）通过调控Wnt/β-联蛋白（β-catenin）信号通路在支气管肺发育不良（bronchopulmonary dysplasia, BPD）模型中的作用及机制。 方法 将野生型C57BL/6及Brg1^f1/f1小鼠随机分为野生型对照组、野生型BPD组、Brg1^f1/f1对照组、Brg1^f1/f1 BPD组（n=5）。培养永生化小鼠肺泡Ⅱ型上皮细胞（immortalized mouse pulmonary alveolar type 2 cell, imPAC2），利用慢病毒转染技术敲低细胞Brg1基因，将细胞分为对照组、空载体组、Brg1敲低组。采用苏木精-伊红染色和免疫荧光检测小鼠肺组织病理改变，Western blot和实时荧光定量PCR检测小鼠肺组织Brg1蛋白和mRNA表达水平，Western blot和免疫荧光检测小鼠肺组织和imPAC2细胞中同源结构域蛋白（homeodomain-containing protein homeobox, HOPX）、表面活性蛋白C（surfactant protein C, SPC）、Wnt/β-catenin信号通路蛋白表达情况，CCK8法检测imPAC2细胞增殖情况以及免疫共沉淀验证imPAC2细胞中Brg1和β-catenin蛋白相互作用情况。 结果 与Brg1^f1/f1对照组、野生型BPD组比较，Brg1^f1/f1 BPD组肺组织肺泡直径、SPC蛋白表达增加，肺血管相对密度、HOPX蛋白表达减少（P<0.05）。与对照组相比，Brg1敲低组细胞增殖能力和SPC、Wnt5a、β-catenin蛋白表达水平及β-catenin蛋白荧光强度升高，HOPX蛋白表达降低（P<0.05）；Brg1与β-catenin蛋白存在相互作用。 结论 Brg1基因可能通过调控Wnt/β-catenin信号通路促进Ⅱ型肺泡上皮细胞增殖，从而影响BPD的发生发展。

Objective To investigate the role and mechanism of Brahma-related gene 1 (Brg1) in regulating the Wnt/β-catenin signaling pathway in a bronchopulmonary dysplasia (BPD) model. Methods Wild-type C57BL/6 and Brg1^f1/f1 mice were randomly divided into four groups: wild-type control, wild-type BPD, Brg1^f1/f1 control, and Brg1^f1/f1 BPD (n=5 each). Immortalized mouse pulmonary alveolar type 2 cells (imPAC2) were cultured, and Brg1 gene was knocked down using lentivirus transfection technology. Cells were divided into three groups: control, empty vector, and Brg1 knockdown. Hematoxylin and eosin staining and immunofluorescence were used to detect pathological changes in mouse lung tissue. Western blot and real-time fluorescent quantitative PCR were used to measure Brg1 protein and mRNA expression levels in mouse lung tissue. Western blot and immunofluorescence were used to detect the expression of homeodomain-containing protein homeobox (HOPX), surfactant protein C (SPC), and Wnt/β-catenin signaling pathway proteins in mouse lung tissue and imPAC2 cells. The CCK8 assay was used to assess the proliferation of imPAC2 cells, and co-immunoprecipitation was performed to verify the interaction between Brg1 and β-catenin proteins in imPAC2 cells. Results Compared to the Brg1^f1/f1 control group and wild-type BPD group, the Brg1^f1/f1 BPD group showed increased alveolar diameter and SPC protein expression, and decreased relative density of pulmonary vasculature and HOPX protein expression (P<0.05). Compared to the control group, the Brg1 knockdown group showed increased cell proliferation ability, protein expression levels of SPC, Wnt5a and β-catenin, and β-catenin protein fluorescence intensity, along with decreased HOPX protein expression (P<0.05). An interaction between Brg1 and β-catenin proteins was confirmed. Conclusions The Brg1 gene may promote the proliferation of alveolar type 2 epithelial cells by regulating the Wnt/β-catenin signaling pathway, thus influencing the occurrence and development of BPD.