Deficiency of matrix metalloproteinase-13 increases inflammation after acute lung injury

Human and animal studies of acute lung injury (ALI) have shown that matrix metalloproteinases (MMPs) play an important role in disease pathogenesis, but despite being detected during ALI, the function of the collagenase MMP-13 in ALI is unknown. To evaluate this role of MMP-13, mice deficient in MMP-13 (KO) were examined after hyperoxic lung injury, and compared to wild-type (WT) mice. There was no survival difference between KO and WT mice. There was also no difference in fibrosis between WT and KO mice, as determined by hydroxyproline content and collagen expression by real-time polymerase chain reaction (PCR). Within the bronchoalveolar lavage (BAL), the KO mice exhibited a significant increase in inflammatory cells, when compared to the WT mice (5.51 x 10