Pulmonary Fibrosis Induced by Acute Paraquat Exposure in C57BL Mice

Objective To explore the pathogenesis of pulmonary fibrosis in mice with acute paraquat (PQ) poisoning.Methods The C57BL mice aged 8 weeks,treated with paraquat (5 mg/ml) at 20 mg/kg,through intraperitoneal injection for 3 consecutive days. The changes of behavior were observed and recorded everyday and the rats were sacrificed on day 1,3,7 respectively after administration. The histopathological,immunochemical examination and count of cells with expressions of MMP-2 and MMP-9 in lung tissues were conducted. Results Compared with the control group,the mice with acute paraquat poisoning appeared dyskinesia,trembling,piloerection,less activity to a certain extent on the third day. Hemorrhage,fibroplasia and stroma thickening in part of the lung were found on 7th day. The expression of MMP-2 and MMP-9 in group of PQ poisoning was significantly up-regulated (P 0.01) compared with the control group.Conclusion MMP-2 and MMP-9 may play an important role in the pathogenesis of pulmonary fibrosis induced by paraquat in C57BL mice.