<p>Light micrographs show cellular intraluminal debris in MV110+24 h lungs (A, B), intact epithelium of C110+24 h bronchiole (C) and bronchiole with denuded epithelium in MV110+24 h lung (D). The basement membrane perimeter of bronchioles was not different between all saccular stage MV and control lungs (E). Epithelial thickness of bronchioles was greater in MV110+24 h fetuses than in controls; however, it was lower in MV110+15 days fetuses relative to 15 days controls (F). The proportion of bronchioles that contained debris within the lumen was increased in MV110+24 h and MV110+15 d fetuses compared with age-matched controls (G). Values that do not share a common letter are significantly different from each other (P<0.05, scale bar = 10 µm in A and B and 20 µm in C and D).</p