CHARACTERIZATION AND IMMUNOHISTOCHEMICAL LOCALIZATION OF THE GLYCOCONJUGATES OF THE RABBIT BLADDER MUCOSA

An impairment of the mucosal glycoconjugates could be an important fac tor in the development of bladder disorders such as interstitial cysti tis. However, very little definitive biochemical information is availa ble on the glycoconjugate components of the mammalian bladder mucosa. In this-study, the mucosa from metabolically radiolabeled rabbit bladd er was separated, delipidated, and digested with protease, and the rel eased glycosaminoglycans and glycopeptides were fractionated. About 80 and 36% of the nondialyzable tritium and S-35 activities, respectivel y, was associated with the sialoglycopeptide fractions. The balance of the total tritium activity in the protease digest was in glycosaminog lycans identified as hyaluronan, chondroitin sulfates, and heparan sul fate. Immunohistochemical examination using anti-heparan sulfate antib odies, including one against mouse syndecan-1, indicated the presence of heparan sulfate proteoglycan in the epithelium. In contrast, there was no significant staining of the bladder epithelium with anti-chondr oitin-4- and 6-sulfate antibodies or hyaluronan-binding protein. The l amina propria and muscle layers showed strong staining with anti-chond roitin-4-sulfate antibody and hyaluronan-binding protein and weak stai ning with anti-chondroitin-6-sulfate antibody. The insignificant level s of glycosaminoglycans in the glycocalyx of bladder mucosa epithelium suggest that glycosaminoglycans may be less important than other glyc oconjugates in maintaining normal epithelial function and in bladder d isorders such as interstitial cystitis. (C) 1996 Academic Press, Inc.