EXPRESSION OF MONOCYTE CHEMOATTRACTANT PROTEIN-1 (MCP-1) BY RAT ALVEOLAR MACROPHAGES DURING CHRONIC LUNG INJURY

Using a well-characterized model of bleomycin-induced pulmonary fibros is in the rat, we determined that there was a time-dependent elaborati on of monocyte chemotactic activity in bronchoalveolar lavage fluid. N orthern hybridization analysis revealed markedly increased expression of rat monocyte chemoattractant protein-1 (MCP-1) mRNA in alveolar mac rophages (AMs) from rats following induction of pulmonary fibrosis. Mo nocyte chemotactic activity was also significantly increased in condit ioned media from AMs retrieved from injured rat lungs. These data sugg est that one important role of AMs in the pathogenesis of chronic infl ammatory lung injury and pulmonary fibrosis is the regulation of monoc yte recruitment and activation within the lung secondary to secretion of monocyte chemoattractants including MCP-1.