弹力蛋白酶和基质金属蛋白酶在肺组织破坏中协同作用的实验研究

目的：采用肺成纤维细胞三维立体培养技术，直接观察弹力蛋白酶和基质金属蛋白酶对肺的主要成分之一胶原组织的降解作用。方法： 用明胶酶谱法和Western blotting法测定MMP-1、2、 3、9和TIMP-1和2 (金属蛋白酶抑制因子), 同时测定胶原含量。结果： TNF-α和IL-1β诱导培养在立体胶原内的肺成纤维细胞产生MMP-1、3和9, 但是只引起少量胶原降解（2.8%±1.5%, P＞0.05），同时加入中性粒细胞弹力蛋白酶(NE), 结果导致胶原完全降解（Ｐ＜0.01）。NE 使MMP-1、2、3和9由非活化的形式转化为较小分子量的活化分子，同时，清除TIMP-1和2。胶原降解后基质发生强烈收缩。结论： 基质金属蛋白酶可直接降解肺内胶原和其它间质组织，导致肺组织破坏，中性粒细胞弹力蛋白酶通过活化基质金属蛋白酶引起或加速细胞外基质的破坏。基质金属蛋白酶与弹力蛋白酶的协同作用可能是肺气肿等肺组织破坏的机理。

Neutrophil elastase activates MMP and induces collagen degradation in three dimensional culture of human lung fibroblasts in type I collagen gels

AIM: To investigate the effects of neutrophil elastase (NE) and matrix metalloproteinases (MMP) in lung fibroblast mediated collagen degradation in three dimensional culture. METHODS: Human lung fibroblasts were cultured in three dimensional collagen gels. TNF-α and IL-1β were added to induce MMPs, and NE was added to the culture media at same time. Collagen content, MMPs and gel areas were determined on day 5. RESULTS: TNF-α and IL-1β induced fibroblast productions of MMP-1, 3, 9 in latent forms. NE cleaved the inhibitors of MMP and activated MMPs into active forms, resulting in completely collagen degradation. CONCLUSION: The results demonstrate that the synergistic interaction between neutrophil elastase and MMPs may be involved in the lung tissue destruction in emphysema and chronic obstructive pulmonary disease.