Utility of Micro CT in a Murine Model of Bleomycin-Induced Lung Fibrosis

Serial micro-CT assessment of the therapeutic effects of rosiglitazone in a bleomycin-induced lung fibrosis mouse model

Objective

The aim of this study was to assess the therapeutic effects of rosiglitazone with serial micro-CT findings before and after rosiglitazone administration in a lung fibrosis mouse model induced with bleomycin.

Materials and Methods

We instilled the bleomycin solution directly into the trachea in twenty mice (female, C57BL/6 mice). After the instillation with bleomycin, mice were closely observed for 3 weeks and then all mice were scanned using micro-CT without sacrifice. At 3 weeks, the mice were treated with rosiglitazone on days 21 to 27 if they had abnormal CT findings (n = 9, 45%). For the mice treated with rosiglitazone, we performed micro-CT with mouse sacrifice 2 weeks after the rosiglitazone treatment completion. We assessed the abnormal CT findings (ground glass attenuation, consolidation, bronchiectasis, reticular opacity, and honeycombing) using a five-point scale at 3 and 6 weeks using Wilcoxon-signed ranked test. The micro-CT findings were correlated with the histopathologic results.

Results

One out of nine (11.1%) mice improved completely. In terms of consolidation, all mice (100%) showed marked decrease from 3.1 ± 1.4 at 3 weeks to 0.9 ± 0.9 at 6 weeks (p = 0.006). At 6 weeks, mild bronchiectasis (n = 6, 66.7%), mild reticular opacity (n = 7, 77.8%) and mild honeycomb patterns (n = 3, 33.3%) appeared.

Conclusion

A serial micro-CT enables the evaluation of drug effects in a lung fibrosis mouse model.