LECTIN-BINDING PROPERTIES OF BOVINE RESTING CARTILAGE

The aim of this study was to evaluate the differential localisation of glycoconjugates of bovine hyaline cartilage matrix by lectin histoche mistry, to compare the results of lectin histochemistry with those tha t can be obtained in the same tissue with PAS and alcian blue. Frozen and paraffin sections were stained with HE, PAS and alcian blue (pH 1. 8). Alcian blue staining was carried out also after 1 and 24 hour dige stion with bovine testicular hyaluronidase. Peroxidase conjugated WGA, PNA and RS lectins were tested on all sections before and after 1 hou r digestion with bovine testicular hyaluronidase. The results show tha t all the lectins used in this study react with sugars linked to prote oglycans of territorial matrix, the reaction being increased in territ orial, and induced in interterritorial matrix by 1 hour hyaluronidase digestion. Alcian blue at pH 1.8 and PAS were complementary, the forme r staining territorial, and the latter interterritorial matrix. After 1 hour hyaluronidase digestion, alcian blue stained also the interterr itorial matrix. These results suggest that lectins react with low mole cular weight proteoglycans and that short hyaluronidase digestion caus es depolymerization of high molecular weight proteoglycans without los s of their glucidic components, allowing: a) penetration of alcian blu e molecules into the macromolecular proteoglycan network; b) an increa se of sugar residuals available for lectin histochemistry. Lectin hist ochemistry can be useful for differential localisation of glycoconjuga tes in bovine cartilage, especially if associated with short hyaluroni dase digestion and conventional histochemical techniques.