Expression pattern of fibronectin and its co-purified proteins in healthy and diseased bladder tissue.

Urinary bladder expression of fibronectin (green) and its co-purified proteins (red) in a representative healthy (left panels) and FIC diseased bladder (right panels). Physiological distribution of fibronectin (green) in healthy bladder (A). Extracellular matrix of the lamina propria mucosae and the muscle tunic show a distinct immunoreactivity for fibronectin, whereas a loss in FIC affected bladder tissue (B), especially in the subepithelial and muscular tunices, is evident. C4a (red) is moderately expressed in the apical transitional cell epithelium of the physiological bladder (C) and disappears in the FIC affected bladder tissue (D). Galectin-7 (red) is expressed especially in umbrella cells of the transitional epithelium and around blood vessels in the lamina propria under normal condition (E). In contrast, expression changes profoundly in FIC affected bladders to distinct expression in the transitional cell epithelium (F). Reactivity of I-FABP (red) throughout all tunices in healthy bladder (G) almost disappears in FIC diseased tissue (H). Thioredoxin (red) reveals a predominant signal in the entire healthy bladder tissue (I) compared to a leakage of thioredoxin into the lumen (arrow) of FIC affected bladder tissue resulting in a slight immunoreactivity of the diseased bladder tissue (J). The blue colour reveals staining of cell nuclei (DAPI). a = Transitional cell epithelium, b = Lamina propria mucosae, c = Muscle tunic, d = Normal vessel.