[Effects of Fuzheng Huayu recipe on MMP-2 activity and type IV collagen expression at fibrotic lung].

OBJECTIVE: To study the mechanism of Fuzheng Huayu (FZHY) recipe against pulmonary fibrosis relating to MMP-2 activity and type IV collagen expression at lung tissue. METHOD: The pulmonary fibrosis model was induced by intratracheal instillation with bleomycin once in rats. The models were divided into 3 groups: model control, FZHY recipe treated, and methylprednisolone (Solu-Medrol) treated group, each group was of 14 model rats. Normal control group with 10 rats was intoxicated with the same amount of saline. From the second day of intoxication, FZHY recipe treated group orally took FZHY recipe at the dosage of 4.6 g x kg(-1) rat wt, methylprednisolone treated group received intraperitoneal injection with 15 mg x kg(-1) rat wt of methylprednisolone, while model and normal controls took the same volume of saline, 1 time each day and lasting for 4 weeks. Lung and body weights were weighed and the lung/body ratio was calculated. Collagens deposition was check with Masson stain, and lung hydroxyproline (Hyp) content was assayed with Jamall's method. Protein expressions of MMP-2/9 and type IV collagen at lung tissue were analyzed with Western blot and of MMP-2/9 activities by gelatin zymography. RESULT: Compared to normal rats, the model control rats had a high lung/body ratio, remarkable collagen deposition, increased Hyp content and the expressions of type IV collagen, MMP-2 and MMP-9 protein at lung tissue, increased MMP-2 activity, in particular active MMP-2 activity, but decreased MMP-9 activity. Compared to model control, FZHY recipe and methylprednisolone obviously attenuated pulmonary collagen deposition, decreased lung/body ratio and Hyp content, downregulated MMP-2 protein expression and activity, in particular active MMP-2 activity, and FZHU recipe had some better actions than methylprednisolone on lung/body ratio, type IV collagen expression and active MMP-2 activity. But both drug groups had no influence on MMP-9 protein expression and activity. CONCLUSION: FZHY recipe has a good action against experimental pulmonary fibrosis and its mechanisms are associated with the inhibition of MMP-2 protein and activity, and with the inhibition of over expression of type IV collagen at lung tissue.

[Feature changes of MMP-2/9 activities and TIMP-1/2 protein expressions during the progression of pulmonary fibrosis in rats].

OBJECTIVE: To investigate the dynamic trends of activities of matrix metalloproteinase (MMP)-2/9 and protein expressions of their inhibitors-tissue inhibitor of matrix metalloproteinase (TIMP)-1/2 during the progression of pulmonary fibrosis in rats so as to get insight of the roles played by MMP-2/9 in lung injury and fibrogenesis. METHODS: Forty-eight SD rats were randomly divided into normal control group (n=18) and bleomycin (BLM)-treated group (n=30). The pulmonary fibrosis was induced by intratracheal injection of BLM once. At the consecutive time of 1 day, 3 days, 1 week, 2, 3, and 4 weeks after intoxication, the lung-to-body weight ratio was calculated and the inflammation and collagen deposition in lung tissue were checked by HE and Masson stainings respectively. Meanwhile, the content of hypdroxyproline (Hyp) in lung tissue was assayed with Jamall's method, the protein expressions of MMP-2/9, TIMP-1/2 were examined by Western blotting, and the activities of MMP-2/9 were detected by gelatin zymography. RESULTS: The histopathological changes in lung tissue in the BLM-treated group from 1 day to 2 weeks after intoxication presented local lesions, broadened alveolar wall and septum, infiltration with lots of inflammatory cells and few of fibroblasts inside alveolar space and septum. At this early stage in the BLM-treated group, the lung-to-body weight ratio was increased significantly, the protein expressions and activities of MMP-2/9 were obviously increased especially for activity of active MMP-2, and the protein expressions of TIMP-1/2 were also increased gradually, as compared with those in the normal control group. From 3 to 4 weeks after intoxication in the BLM-treated group, the alveolar structure was damaged, parts of the alveolar space collapsed and replaced by collagens and fibroblasts, and the alveolar wall and septum obviously widened with remarkable fibrotic characteristics, as compared with those in the normal control group. Meanwhile, the lung-to-body weight ratio and the activities of MMP-2/9 were decreased in the BLM-treated group as compared with those in the same group at 2 weeks after intoxication, but the content of Hyp and the protein expressions of TIMP-1/2 were both increased dramatically, especially at 4 weeks after intoxication. CONCLUSIONS: During the lung fibrogenesis induced by BLM in rats, the alveolar inflammation is the most important alteration with enhanced MMP-2/9 activities in the early stage. While in the late stage, the main change is displayed as pulmonary fibrosis, characterized by increased TIMP-1/2 and declined MMP-2/9 activities.