Glycoconjugate histochemistry in the glycocalyx of guinea pig middle ear mucosa

An attempt was made to determine the composition of oligosaccharide side chains in the apical cell surface glycocalices of the middle ear epithelium. This glycoconjugate is located on the innermost luminal surface, but its function is still unknown. The lectins evaluated included Triticum vulgare, Canavalia ensiformis, Maclura pomifera, Arachis hypogaea, Ricinus communis I (RCA-I), and Limax flavus. The staining results obtained with the six different lectin probes in the Lowicryl K4M-embedded guinea pig middle ear mucosa suggest that the glycocalyx contains beta-D-N-acetylglucosamine, sialic acid, and beta-D-galactose in the major carbohydrate moiety. The present study also indicates that a polarity exists on the cell surfaces in the distribution pattern of the carbohydrate component, especially those of beta-galactosyl residues, as revealed by RCA-I binding. This may imply functional separation of the epithelial cells.