Azelastine hydrochloride (Azeptin) inhibits peplomycin (PLM)-induced pulmonary fibrosis by contradicting the up-regulation of signal transduction

Inhibition of peplomycin (PLM)-induced pulmonary fibrosis by azelastine hydrochloride (Azeptin) was examined using ICR mice, and the effects of both drugs on signal transduction were investigated. Microscopically, Azeptin (a total of 56 mg/kg for 28 days) suppressed pulmonary fibrosis in mice which received an i.p. injection of a total of 60 or 75 mg/kg PLM. In parallel with the microscopic findings, smaller amounts of collagen were synthesized in the lungs of Azeptin-injected mice. PLM enhanced the expression of interleukin-1 beta-and transforming growth factor-beta-mRNA in lungs. In contrast, Azeptin suppressed the expression. Compatible with these in vivo results, Azeptin and PLM contradictively regulated protein tyrosine phosphorylation and c-myc mRNA expression in human gingival and mouse pulmonary fibroblasts. In addition, NF-kappa B was activated by fibroblast treatment with 5 mu g/ml PLM for 1 h, but intranuclear NF-kappa B was decreased by cell treatment with 10(-5) M Azeptin. From these results, it is concluded that Azeptin inhibits PLM-induced pulmonary fibrosis by antagonizing the up-regulation of signal transduction.