大鼠肺纤维化模型间质成纤维细胞和肺泡巨噬细胞基质金属蛋白酶2及膜型基质金属蛋白酶mRNA的表达

目的探讨肺间质成纤维细胞和肺泡巨噬细胞基质金属蛋白酶2(MMP-2)和膜型基质金属蛋白酶(MT1-MMP)mRNA在肺纤维化中的表达及意义.方法清洁级SD大鼠50只,随机分为10组,实验组5组气管内注射盐酸博莱霉素A5,对照组5组代以等剂量生理盐水.于注射后1d、3d、7d、14d、28d分离和提取肺间质成纤维细胞及肺泡巨噬细胞,应用逆转录多聚酶链反应(RT-PCR)方法,观察其MMP-2及MT1-MMPmRNA的动态变化.结果(1)博莱霉素作用后1d成纤维细胞MMP-2基因转录就明显增强,达对照组的2.05倍(t=10.667,P＜0.01),且一直维持于高水平,直到用药28d才略下降.而此过程中肺泡巨噬细胞MMP-2mRNA的转录极微弱,仅于实验第1d较对照组增高(t=3.27,P＜0.05).(2)成纤维细胞和肺泡巨噬细胞MT1-MMPmRNA的转录均有增强,前者于实验第14d和第28d时分别为对照组的2.1倍(t=4.823,P＜0.01)和1.8倍(t=4.016,P＜0.01),后者于第28d时为对照组的2.4倍(t=5.851,P＜0.01).结论(1)成纤维细胞不单纯是肺纤维化效应细胞,其通过MMP-2基因转录的增强,参与了肺基膜结构的损伤,参与了肺间质纤维化的启动机制.(2)实验中后期成纤维细胞和肺泡巨噬细胞MT1-MMP表达增强,有助于MMP-2的持续活化,促进肺间质纤维化的进展.

mRNA expression of matrix metalloproteinase-2 and membrane type matrix metalloproteinase in pulmonary fibroblasts and macrophages of rat pulmonary fibrosis model

Objective To study the changes and significance of MMP 2 and MT1 MMP mRNA expressions in fibroblasts and macrophages of rat pulmonary fibrosis model. Methods Fifty pathogen free Sprague Dawley rats were randomly divided into ten groups Five groups were instillated with bleomycin A 5(BLM A 5) intratracheally,while 5 control groups with normal saline instead Pulmonary interstitial fibroblasts and alveolar macrophages were isolated at day 1,3,7,14,28th after BLM exposure. The mRNA expression of MMP 2 and MT1 MMP was evaluated by RT PCR quantitative analysis. Results (1) The MMP 2 gene expression of fibroblasts increased 2 05 times( t =10 667, P <0 01) higher than that of control in 24 hours after bleomycin instillation and remained at the high level until the 28th day after exposure It was only slightly increased in macrophages at the first day ( t =3 27, P <0 05)and dropped down to the level of control during pulmonary fibrosis (2) The mRNA expressions of MT1 MMP were enhanced both in fibroblasts and macrophages of fibrosis groups They were 2 1 times( t =4 823, P <0 01)higher than that of control at the 14th day and 1 8 times( t =4 016, P <0 01)at the 28th day, respectively, in fibroblasts, while it was 2 4 times( t =5 851, P <0 01)higher than that of control at the 28th day in macrophages. Conclusions (1)Fibroblasts not only were the target cells but also involved in the damage of the pulmonary basement membrane and in the initiation of pulmonary fibrosis mediated by up regulation of the mRNA expression of MMP 2 (2)The highly expressed MT1 MMP of fibroblasts and macrophages in the late stage of pulmonary fibrosis participated in the activation of pro MMP 2 to promote the progression of pulmonary fibrosis