[Effect of peptides, isolated from the tracheal mucosa, on alveolar macrophages and the nature of the course of fibrosing alveolitis in the rat].

Rats with bleomycin-induced pulmonary fibrosis were treated with a complex of low-molecular weight peptides isolated from the tracheal mucosa (PTM). Cytological examinations of bronchoalveolar lavage fluid from the animals receiving PTM revealed increases in the number of alveolar macrophages (AM) as compared to that in saline-treated rats. The AM obtained from PTM-treated animals also showed an enhanced phagocytic activity, as well as increased superoxide anion production when stimulated with the opsonized zymosan. However, basal superoxide production after PTM administration was reduced to normal values. These PTM effects of the AM paralleled the reduction of pulmonary fibrotic changes and myocardial hypertrophy. The findings suggest that the AM functional activity is mediated by PTM.