Temporal Expressions and Significances of Matrix Metalloproteinases-13 and Tissue Inhabitor of Metalloproteinases-1 in Lung of Newborn Rats with Hyperoxia Induced Chronic Lung Disease

Objective To observe temporal expression of matrix metalloproteinases(MMP-13) and tissue inhibitor of metalloproteina-ses-1 (TIMP-1) in lung of newborn rats with hyperoxia induced chronic lung disease (CLD),and to explore the relationship of CLD with MMPs.Methods The neonatal rats within 24 hours after birth were randomly divided into hyperoxia-exposed group(n=40) and control group(n=40).On postnatal 1,3,7,14 and 21 days,lung tissue of rats in 2 groups were collected.Lung histological changes were evaluated by hematoxylin and eosin and Masson stain;Collagen Ⅰ was detected by enzyme linked immunoadsorbent assay;MMP-13 and TIMP-1 were identifide by immunohistochemistry.Results Exposured to hyperoxia enviroment for 21 days,the number of alveolar decreased,terminal air space enlarged,inter-alveolar septa thickened,and deposition of interstitial collagen fibers.On 14 and 21 days,collagen Ⅰ in the lung of hyperoxia-exposed group increased significantly compared with that of control group(P0.01,0.001).MMP-13 and TIMP-1 were expressed in cytoplasmic of epithelial cells and microvascular endothelial cells,interstitial cells and pulmonary macrophages.Compared with control group,the expression of MMP-13 in the lung of hyperoxia-exposed group kept the same level on 1,3,7,14 day(Pa0.05),obviously decreased on 21 day(P0.05);with time of hyperoxia exposure extended,TIMP-1 increased continuously,significantly enhanced on 14,21 day(Pa0.01).Conclusions There exist imbalances of MMP-13/TIMP-1 in lung of newborn rats with hyperoxia induced CLD.And which maybe play an important role in extracellular matrix abnormal deposition at the later phase of hyperoxia exposure.