Objective: To observe the protective role of recombinant Chinese interferon-gamma (INF-gamma) in pulmonary injury (PI) induced by bleomycin (BLM) in C57 mice.
Methods: Seventy-five C57 mice were randomly divided into a control group and groups treated with BLM, BLM + INF-gamma minimum dose (0.25 microg/d), BLM + INF-gamma medium dose (0.5 microg/d), and BLM + INF-gamma maximum dose (1.0 microg/d, with 15 mice each). PI was induced by BLM, and intervention with different doses of INF-gamma was carried out in the experiment groups, but no treatment was administered in the control mice. Measurement of pulmonary hydroxyproline (Hyp), image analysis of collagen I and III, and measurement of the ratio between lung alveoli and interstitial areas were performed.
Results: Lung Hyp content and collagen I and III deposition were increased as compared with the control after administration of BLM (0.78 +/- 0.08 vs 0.65 +/- 0.06, P < 0.01; 0.048 +/- 0.006 vs 0.004 +/- 0.001, P < 0.01). Hyp content and collagen I and III deposition were reduced in group INF-gamma maximum dose (0.67 +/- 0.08 vs 0.78 +/- 0.08, P < 0.05; 0.008 +/- 0.001 vs 0.048 +/- 0.006, P < 0.01). The ratio of lung collagen to lung tissue areas was increased with the increase of INF-gamma doses (1.78, 0.12, 0.67, 0.73, 1.65 respectively).
Conclusion: INF-gamma is effective in alleviating BLM induced pulmonary injury in mice, possibly by inhibition of transformation of fibroblasts to myofibroblasts and collagen synthesis.