Effects of montelukast, a cysteinyl-leukotriene type 1 receptor antagonist, on the pathogenesis of bleomycin-induced pulmonary fibrosis in mice

Cysteinyl-leukotrienes are potent mediators involved in various inflammatory diseases and lung disorders such as asthma However their precise role in the pathogenesis of pulmonary fibrosis is unknown In the present study we investigated the effect of montelukast a cysteinyl-leukotriene type 1 receptor antagonist on bleomycin induced pulmonary fibrosis in mice Montelukast (10 mg/kg/day) was orally administered to the bleomycin-induced pulmonary fibrosis mice for 3 days before and 14 days after intratracheal instillation of bleomycin We evaluated the effects of montelukast on the development of pulmonary fibrosis in these mice and investigated the expression of venous cytokines and two cysteinyl-leukotriene receptors Treatment with montelukast significantly attenuated the Increased fibrotic area and hydroxyproline content in the fibrotic lungs of bleomycin instilled mice Montelukast treatment also decreased mRNA levels of IL 6 IL-10 IL-13 and TGF-beta 1 all of which were elevated in fibrotic lungs In fibrotic lungs TNF-alpha and IL-1 beta mRNA levels were Increased and IFN-gamma mRNA levels were decreased but montelukast did not affect these mRNA levels Furthermore cysteinyl-leukotriene type 1 receptor mRNA levels were increased whereas cysteinyl-leukotriene type 2 receptor mRNA levels were decreased in fibrotic lungs Montelukast treatment induced the recovery of cysteinyl leukotriene type 2 receptor mRNA levels to normal control levels but did not change cysteinyl leukotriene type 1 receptor mRNA levels These results suggest that montelukast exhibits its beneficial effects by inhibiting the overexpression of IL 6 IL 10 IL-13 and TGF-beta 1 and by modulating the homeostatic balance between the cysteinyl-leukotriene type 1 and type 2 receptors (C) 2010 Elsevier B V All rights reserved