[Study on the expression of matrix metalloproteinase-9 in lung fibroblasts of rat with acute paraquat poisoning].

OBJECTIVE: To investigate the expression and effect of matrix metaloproteinases-9 in lung injury of rats with acute paraquat poisoning. METHODS: 50 SD rats were randomly divided into control group and poisoned group. At 1, 3, 7, 14, 28 days after exposed to paraquat, five rats of each group were used to assess lung pathological changes, and the expression of MMP-9 mRNA in lungs was evaluated by RT-PCR. RESULTS: (1) The expressions of MMP-9 protein and mRNA markedly increased at the first day of paraquat poison, reached the peak at the 7th day, decreased slowly afterwards. (2) The expressions of MMP-9 protein and mRNA markedly increased at 1, 3, 7 days. The protein expression of MMP-9 returned to baseline level at the 28th day, and mRNA expression of MMP-9 returned to baseline at the 14th day. CONCLUSION: The expression of MMP-9 in lung fibroblasts is up-regulated in silicotic fibrosis model.