RESUMO
Objective To explore the role of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) in hyperoxia-induced lung injury in preterm rats. Methods At the 2 nd postnatal day Sprague-Dawley preterm rats were randomly assigned to air group and hyperoxia group (exposed to about 85% of O 2). At 3,7,14 and 21 days after exposure, six rats of each group were used to assess lung histologic changes and expression of MMP-2, MMP-9, TIMP-1 and TIMP-2 in lungs by immunohistochemistry. At 3,7 and 14 days after exposure, gelatinase activity in bronchoalveolar lavage fluid (BALF) of another six rats in each group by gelatin zymography was examed. Results Except 3 d after exposure, hyperoxia group showed lung injury characterized by subacute alveolitis and inhibition of lung development. Expression of MMP-2, MMP-9, TIMP-1 and TIMP-2 in hyperoxia group was stronger than that in air group at every time (P
