Investigation of effects of antibiotics on experimental bleomycin-induced pulmonary fibrosis

Abstract

Several reports have shown results of antifibrotic action of antibiotics in experimental models of idiopathic pulmonary fibrosis (IPF). Effects of antibiotics on course of IPF has been also investigated in the present work. IPF model was created in male rats Vistar (n = 41) using intratracheal instillations of bleomycin 10 mg/kg followed by intramuscular injections of cefotaxime (n = 10) or erythromycin (n = 10) after the 5th day during 8 days. We evaluated bronchoalveolar lavage fluid (BALF) cell count and differentiation, oxidative activity of alveolar macrophages (AM) using luminol-dependent chemiluminescence, and histological changes in the lung tissue. Both the antimicrobials decreased total cell count in BALF, increased AM and lymphocyte numbers and decreased neutrophil number. Erythromycin increased oxidative activity of AM and cefotaxime reduced it in some degree. Structure of the lung tissue after 14 days of administration of antibiotics did not differ from that seen in rats received bleomycin alone but the formers had more severe vascular lesions such as vasculitis, perivascular fibrosis, full-blooded capillaries. Therefore, antibiotics inhibited neutrophil-related inflammation, heterogeneously affected oxidative activity of AM, caused vascular lesions and did not influence fibrosis. These results do not suggest antibiotics to be used as therapeutic drugs in IPF.