Expressions Of Matrix Metalloproteinase 9 And Tissue Inhibitor Of Metalloproteinases 1 In Lung Tissues Of Neonatal Rats With Intrauterine Infection

Objective: To investigate the changes and mechanisms of matrix metallopeptidase 9 (MMP-9) and tissue inhibitor of metalloproteinases 1 (TIMP-1) in the lung tissues of neonatal rats with intrauterine infection (II). Methods: The pregnant rats were divided into the intrauterine infection group (group LPS) and the control group (group NS). The rats in group LPS were intraperitoneally injected lipopolysaccharide (LPS) to establish the II animal model; the neonatal rats of the two groups were selected on D1, D3, D7, and D14 after birth for the HE staining and radiation alveolar count (RAC); meanwhile, the protein expression and mRNA quantification of MMP-9 and TIMP-1 in the lung tissues were detected. Results: Group LPS showed significantly increased infiltration of alveolar inflammatory cells and decreased RAC than group NS. The protein and mRNA expressions of MMP-9 in group LPS were significantly higher than group NS on D3, D7, and D14, and those expressions in group LPS showed no significant difference. The protein and mRNA expressions of TIMP-1 in group LPS were gradually increased after birth, and showed significant difference with group NS on D3, D7, and D14. Conclusions: The post-II expressions of MMP-9 and TIMP-1 in the lung tissues of the neonatal rats were significantly increased, and its imbalance might play an important role in repairing lung injuries and abnormalities.