Protective effects of curcumin against amiodarone-induced pulmonary fibrosis in rats

(1) We have studied whether curcumin prevents amiodarone-induced lung fibrosis in rats. Intratracheal instillation of amiodarone (6.25 mg kg(-1) on days 0 and 2, and then killed on day 3, day 5, week 1, week 3 and week 5 after amiodarone administration) induced increases in total protein and lactate dehydrogenase (LDH) activity on days 3 and 5 in bronchoalveolar lavage fluid (BALF). Total cell counts, alveolar macrophages, neutrophils and eosinophils recovered by BAL, and lung myeloperoxidase (MPO) activity were significantly higher in amiodarone rats. (2) Tumor necrosis factor-alpha (TNF-alpha) release after lipopolysaccharide (LPS) stimulation and superoxide anion generation after phorbol myristate acetate (PMA) stimulation were higher in the alveolar macrophages of amiodarone rats at 3 and 5 weeks postamiodarone instillation than in controls. Amiodarone also induced increases in transforming growth factor-beta1 (TGF-beta1) expression, collagen deposition, type I collagen expression and c-Jun protein in lungs. (3) Curcumin (200 mg kg(-1) body weight after first amiodarone instillation and daily thereafter for 5 weeks)-treated amiodarone rats had reduced levels of protein, LDH activity, total cell numbers and differential cell counts in BALF. LPS-stimulated TNF-alpha release and PMA-stimulated superoxide generation were significantly suppressed by curcumin. Furthermore, curcumin inhibited the increases in lung MPO activity, TGF-beta1 expression, lung hydroxyproline content, expression of type I collagen and c-Jun protein in amiodarone rats. Our results have important implications for the treatment of amiodarone-induced lung fibrosis.