MMP9 and TIMP1 expression in human embryonic lung fibroblasts induced by supernatant of alveolar macrophage exposed to silica

Objective To observe the expression of metalloproteinase-9(MMP9)and tissue inhibitor of metallproteinnase-I(TIMP1)in human embryonic lung fibroblasts(MRC-5)induced by supernatant of alveolar macrophage(AMs)exposed to silica.Methods Rat AMs and MRC-5 were made into a model in vitro.MMP9 and TMIP1 mRNA levels in the induced MRC-5 were detected with RT-PCR technology at the culture time of 0,12,24,36,48,and 60 hours.Results Expression of MMP9 and TMIP1 could be induced by silica exposed AMs and there was a good time effect relationship between MMP9 and TIMP1 mRNA level and culture time.Increasing of MMP9 expression appeared earlier than TMIP1.Conclusion The result indicates that the biosyn thesis change of metalloproteinases occurs at transcription level.