Correlation between the Airway Branching Patterns and the Heterogeneous Distribution of the Lesions in Bleomycin-Injured Mouse Lung: A 3-D Morphometric Study.

The possible roles of airway branching patterns on the pathogenesis of lung diseases, especially on the heterogeneous distribution of the lesions, were examined through three-dimensional (3-D) morphometric analysis of a mouse lung injury, induced by bleomycin. On serial sections of a mouse lung damaged by subcutaneous injection of bleomycin, we performed a computer-assisted reconstruction of the lung for visualizing the relation of airways with the distribution of the lesions, and defined the features of bronchial routes to each lesion by four parameters: LTB; the distance from the hilum, Ng; generation numbers, RD(min); irregularity of airway branching, and thetaTB; the grade of airway recurrence. Among these four parameters, only thetaTB was found to correlate with the severity of lesions (p < 0.05 by an ANOVA test), which was proved by a posthoc test (p < 0.0001). These results showing the acini supplied by recurrent branches are more prone to be damaged than those by non-recurrent branches suggest that branching patterns may underlie the heterogeneous distribution of lesions in diffuse interstitial lung diseases.