Effects of iloprost on bleomycin-induced pulmonary fibrosis in rats compared with methyl-prednisolone

Prostacyclin (PGI2) has been shown to inhibit the expression of pro-inflammatory and pro-fibrotic mediators in pulmonary fibrosis. In this study, we aimed to test the preventive effects of intraperitoneally administered iloprost, a stable PGI2 analog, on bleomycin-induced pulmonary fibrosis in rats and to compare the effects of iloprost with the effects of methyl-prednisolone, a traditional therapy.

Rats were randomly allocated into four groups: 1. Saline alone (n=6); 2. Bleomycin+placebo (n=7); 3. Bleomycin+methyl-prednisolone (n=7); 4. Bleomycin+iloprost (n=7). Fibrotic changes in the lungs were demonstrated by analyzing the cellular composition of bronchoalveolar lavage fluid, histological evaluation and lung hydroxyproline content.

Fibrosis was made in the lungs of rats by bleomycin experimentally. Fibrosis scores in the methyl-prednisolone and the iloprost groups were significantly lower than in the placebo group (p<0.05). Furthermore, the score of the iloprost group was significantly lower than the score of the methyl-prednisolone group. The hydroxyproline content was significantly less in the methyl-prednisolone and the iloprost groups (p<0.05). In the placebo group, the neutrophil percentage in bronchoalveolar lavage was significantly higher than in the other groups, whereas the macrophage percentage in placebo group was significantly lower (p<0.05).

Iloprost has protective effect on the pulmonary fibrosis induced by bleomycin and it may be more effective in decreasing fibrotic changes than methyl-prednisolone.