Lung function dynamics for noninvasive severity evaluation of lung fibrosis in rats

抄録

Bleomycin-induced lung fibrosis model is widely-used for the study of mechanism and therapeutic agents. In this study, lung function measurements of respiratory frequency and tidal volume were applied to estimate the severity of inflammation and fibrosis in Bleomycin-induced lung fibrosis model in rats. A single intratracheal instillation of bleomycin (2.5 mg/kg) was used for inducing lung fibrosis. Lung function measurements were performed at 3, 7, 14, 21 and 28 days post-ITI. Inflammatory cell count, lactate dehydrogenase (LDH) activity in the bronchoalveolar lavage fluid (BALF), and light microscopic examination of lung injury were followed. The increasing number of total cells and neutrophils in BALF along with the sustained increase in macrophages and lymphocytes at days 3 and 7. BALF LDH level was significantly increased compared up to 14 days. On day 3, the infiltration of neutrophils in the alveolar spaces was seen. These changes were developed into marked peribronchiolar and interstitial infiltration by inflammatory cells, and extensive thickening of interalveolar septa on day 7. At 14, 21 and 28 days mild peribronchiolar fibrosis was shown together with the inflammatory cell infiltration. The results of lung functions show significant consistencies compared to the results of other tests.