RESUMO
OBJECTIVE: To investigate the interventional effect of the Chinese herbal preparation Xi Fu Pai Chen(XFPC) on pulmonary inflammation and fibrosis in rats with silicosis. METHODS: A total of 144 adult specific pathogen free male SD rats were randomly divided into 6 groups: blank control group, silicosis model group, drug administration control group and groups of low-dose,medium-dose and high-dose XFPC, with 24 rats in each group. Lung silicosis model was established by single inhalation tracheal instillation method, which was treated with 50.0 g/L silica suspension, in groups except in the blank control group. On the 7 th day of modeling, the rats in the drug administration control group were orally given tetrandrine(5 mg/kg body weight), while those in the low-, medium-and high-dose groups were given 43, 86 and 192 g/L of XFPC by atomization inhalation once a day for 20 minutes, 5 days a week for 4 weeks. At the end of drug administration, the histopathological changes of the lung were observed. The number and classification of cells in bronchoalveolar lavage fluid(BALF)were examined, and the levels of malondialdehyde(MDA) and interferon-gamma(IFN-γ) in BALF were measured by enzyme-linked immunosorbent assay. RESULTS: On the 7 th day after modeling, the body weight in the drug administration control group and XFPC high-dose group decreased compared with the blank control group(P<0.05). On the 35 th day after modeling, the body weights of rats in the other 5 groups were lower than that in the blank control group(P<0.05). The pathological changes of lung tissue(infiltration of inflammatory cells, fibrosis and size of silicon nodule) in drug administration control group and XFPC low-dose group were better than those in silicosis model group by naked eyes and under light microscope. The lung coefficient, the proportion of neutrophils and the level of MDA and IFN-γ in BALF of the drug administration control group and XFPC low-dose group decreased(P<0.05), and the proportion of macrophages in BALF increased(P<0.05) compared with the silicosis model group. There was no significant difference in lung coefficients and the relevant indices of BALF between XFPC medium-, high-dose groups and silicosis model group(P>0.05). CONCLUSION: Low dosage XFPC can improve pulmonary fibrosis and inflammation in rats with silicosis, and its mechanism of action may be related to reducing the levels of IFN-γ and MDA in BALF.