Figure 8

Model of MIF/A1-I3 complex formation and paracellular transport through the urothelium. In the intact bladder (A), A1-I3 (not synthesized by the bladder and most likely of liver origin) is located in the lamina propria immediately below the urothelium and throughout the interstitial spaces in the bladder. MIF is found in the urothelium, in the basal and intermediate cells. The lamina propia shows only weak MIF immunostaining. There is basal MIF release (and MIF/A1-I3 complexes) into the bladder lumen, however, A1-I3 is not located in the urothelium of intact rats. After SP-induced neurogenic inflammation (B), there is upregulation of MIF production in the urothelium, increased MIF staining in the lamina propria and greater release of MIF and MIF/A1-I3 complexes. Paracellular transport of A1-I3 can be observed in the urothelium. In addition, apical (umbrella cells) are now observed co-localizing both MIF and A1-I3.