1991 Volume 22 Issue 1 Pages 3-12
Changes in sugar residues in articular cartilage during the fetal and postnatal development of rabbits were studied by light and electron microscopy using biotinylated lectins as a probe. Rabbits were divided into eight different age groups; fetal (15, 21, 28 days) and postnatal (1, 3, 6 months, 1 year, and over 2 years). The articular cartilage at the distal end of the femur was cut into slices of about 1 mm thickness, and was fixed with 2.5 % glutaraldehyde in phosphate-buffered saline (PBS) for 2 h at 4℃. Frozen sections of about 5 pm thickness were cut, immersed in 1 % bovine serum albumin-PBS, and in biotinyl lectins (WGA, RCA, ConA, PHA-E4, PHA-L, DSA, ECA, SBA, DBA, HPA, GS-I, PNA, LTEA-I, and Lotus), followed by ABC reaction and examination by light microscopy. Some of the fixed slices were embedded in Lowicryl K4M, ultrathin sections were made, and then treated with biotinylated lectins and streptavidin-colloidal gold conjugates followed by observation under a transmission electron microscope. WGA, RCA, ConA, and PHA-E4 were positive in chondrocytes throughout the development of cartilage. WGA also bound to the intercellular matrix. DSA, ECA, and PHA-L stainings were definitely positive in fetal and 1 and 3 month old postnatal rabbits while faint or almost negative in postnatal individuals older than 6 months. Under the electron microscope, WGA binding sites were found in Golgi complex, secretory granules, cell membrane and intercellular matrix. DSA bound mainly to Golgi complex, secretory granules and rough endoplasmic reticulum. DSA, ECA and PHA-L are known to posses an affinity for Galβ1→4GlcNAc sugarlinkage in complex-type glycoconjugates. It is suggested that such type of sugar structure is, to some degree, involved in the early development and formation of the articular cartilage.
