[Effect of atorvastatin on MMP-9 and TIMP-1 levels in bronchoalveolar lavage fluid and serum of rats with bleomycin-induced pulmonary fibrosis].

OBJECTIVE: To investigate the effects of atorvastatin on matrix metalloproteinase-9 (MMP-9) and the tissue inhibitor-1 of matrix metalloproteinase (TIMP-1) levels in bronchoalveolar lavage fluid (BALF) and serum of rats with experimental pulmonary fibrosis. METHODS: Pulmonary fibrosis was induced by intratracheal administration of bleomycin in 30 female rats, which were further divided into two groups: Group M (without treatment) and Group A (treated with atorvastatin 10 mg/kg); control group (n = 5, Group C) was intratracheally administrated with same volume of saline. Five animals were sacrificed at 2 weeks (M2 and A2), 4 weeks (M4 and A4) and 6 weeks (M6 and A6) after model establishment, respectively. Lung tissue samples were harvested and prepared for HE and Masson's trichrome staining. Concentrations of MMP-9 and TIMP-1 in BALF and serum were measured by ELISA. RESULT: The severity of inflammation and pulmonary fibrosis was significantly reduced in Group A than that in Group M, especially at week 6. No significant difference was noted in the serum concentrations of MMP-9 and TIMP-1 among the Group M, A and Group C. The BALF concentrations of MMP-9 in Group M2 and M6 were significantly higher than those in Group C (P < 0.01 and 0.05), whereas those in the atorvastatin groups (A2, A4 and A6) were lower than those in M2, M4 and M6. Although the MMP-9 was still higher in Groups A2 and A4 than in the Group C, there was no significant difference in MMP-9 between Group A6 and Group C. TIMP-1 levels in BALF were significantly higher in M4 and M6 than Group C (P < 0.01 and 0.05), there were no significant differences between Group M2 and Group C. The TIMP-1 levels in BALF of atorvastatin groups were significantly lower than those of model groups and control group (P < 0.01 and 0.05), which resulted in a significantly increased ratio of MMP-9 to TIMP-1 in the atorvastatin groups. CONCLUSION: Atorvastatin inhibits the synthesis and release of MMP-9 and TIMP-1 in the lung tissue of rats with bleomycin-induced pulmonary fibrosis, and has no significant effect on circulating MMP-9 and TIMP-1, which may be associated with the attenuation of experimental pulmonary fibrosis in rats.