Experimental Study On The Preventive Effect Of Curcumin On Bleomycin-induced Pulmonary Fibrosis In Rats

Object:To evaluate the effect of curcumin on the pulmonary function and extracellular matrix in rats which were induced pulmonary fibrosis by bleomycin (BLM). And the study of curcumin on the proliferation of human embryo lung fibroblast MRC-5 cells was performed.Methods:In vitro: 144 male Sprague-Dawley rats were randomized into 6 groups (24 rats in each group), sham group, model control group, prednisone group, curcumin with low dose 5 mg group per 100g of body weight, curcumin with middle dose 10 mg group per 100g of body weight and curcumin with high dose 20 mg group per 100g of body weight. Rats in all groups except rats in the sham group were injected with BLM intratracheally. Curcumin with different doses were given by gavage one time everyday. On Day 7, 14 and 28, lung function (inspiratory resistance, maximual voluntary ventilation, forced vital capacity, FEV0.2/FVC, peak inspiratory flow) was determined; hydroxyproline concentrations in lung homogenates were assayed; and serum levels of procollagen III N-terminal peptide, IV-collagen, laminin and hyaluronic acid were measured in eight rats from each group.In vivo: MTT colorimetry was used for assaying proliferation of MRC-5. The proliferation curves of MRC-5 were drawn in a week. After cells were incubated with different concentration of curcumin for 24 hours, the inhibiting effects of curcumin were determined by absorbance at 570nm. The content of collagen were determined by the optical density at 540nm after the cells were dyed by Pico Sirius Red.Results:Administration of curcumin in different doses improved lung function of BLM-induced fibrotic rats and it decreased the concentration of procollagenⅢN-terminal peptide,Ⅳ-collagen, laminin and hyaluronic acid in the serum and the level of hydroxyproline in lung homogenates compared with those levels in the model control group. In vitro, curcumin suppressed the proliferation and collagen synthesis of MRC-5. Conclusion:Administration of curcumin suppressed BLM induced pulmonary fibrosis in rats indicated by improved respiratory function, probably resulting from a decrease in the content of extracellular matrix. The inhibitory effect of curcumin on the proliferation and collagen synthesis may contribute the amelioration of the fibrosis.