Effects of curcumin in treatment of experimental pulmonary fibrosis: A comparison with hydrocortisone

To compare curcumin with hydrocortisone for treating bleomycin-induced pulmonary fibrosis (BLMPF), four groups of rats were injected with 1.5 mg/kg bleomycin intratracheally. Then the Group HC rats were treated with three injections of 2 mg/kg hydrocortisone i.p.; Group CH and CL rats, respectively, were orally given 500 or 250 mg/kg curcumin daily; and Group PC rats were given deionized water alone. After 28 days of treatment, lung samples were examined by H-E staining, Masson's staining and immunohistochemical analyses and pulmonary type I collagen (Col-I), inducible nitric oxide synthetase (iNOS) and transforming growth factor-β1 (TGF-β1) were determined by Western blotting and real-time RT PCR analyses. The results showed that (1) Group PC rats had histopathological characteristics of BLMPF with significant increase in their protein/mRNA expressions of Col-I (+114%/+173%), iNOS (+146%/+523%) and TGF-β1 (+476%/+527%) (P < 0.01); (2) in Group HC, CH and CL rats, protein/mRNA expressions of Col-I (−39%/−52%, −31%/−57%, −33%/−58%), iNOS (−31%/−51%, −31%/−79%, −31%/−47%) and TGF-β1 (−64%/−78%, −75%/−74%, −81%/−79%) were significantly lower than Group PC (P < 0.05); (3) except for levels of TGF-β1 protein, there was no significant difference among Group CH, CL and HC rats (P > 0.05). It suggests that curcumin may play a similar role as hydrocortisone in preventing BLMPF.