Figure 5

Sub-epithelial fibrosis in Bpifa1^−/−Evi1^Jbo/+ and Evi1^Jbo/+ middle ears. Picrosirius red staining showing collagen fibres in the sub-epithelial connective tissue of WT (A) and Bpifa1^−/− (B) ME. Staining intensity increases in the inflamed and expanded mesenchyme of Evi1^Jbo/+ (C) and Bpifa1^−/−Evi1^Jbo/+ (D) ME indicating increased deposition of collagen fibres. IHC analysis of ME sections shows no α-SMA staining in the thin sub-epithelial mesenchyme of WT (E) and Bpifa1^−/− (F) ME epithelium but intense α-SMA staining in the lower half of the expanded mesenchyme of Evi1^Jbo/+ (G) and Bpifa1^−/−Evi1^Jbo/+ (H) ME. Arrowheads indicate positive staining. Data is representative of n = 3 mice for all genotypes. Scale bar: 500 μm for 4x objective images and 50 μm for 60x objective images (insets).