Abstract
The glycosaminoglycans that exist in rabbit bone marrow were analyzed chemically, and their in situ localization was studied immunohistochemically. Femoral bone marrow of 3-month-old rabbits was defatted with organic solvents. Glycosaminoglycans were prepared from the defatted tissue after its digestion with pronase, treatment with mild alkali, and then digestion with DNase-I. The tissue contained glycosaminoglycans equivalent to 195 mg of hexosamine per femur, which accounted for 27.3% of the total hexosamine in the tissue. Studies with hyaluronidase from Streptomyces hyalurolyticus and chondroitinase ABC showed that the glycosaminoglycans were composed of hyaluronic acid (16% of the total glycosaminoglycan) and chondroitin 6-sulfate (79%). The chondroitin 6-sulfate was separated on Bio-Gel A-0.5m gel into two molecular species with mol wt of greater than 12,000 (Kd greater than 0.2) and approximately 8,000 (Kd = 0.47). Bone marrow digested with chondroitinase ABC and then treated with three monoclonal antibodies 4/8/9-A-2, 5/6/3-B-3, and 5/6/1-B-5, which were specific for unsaturated 4-sulfated, 6-sulfated, and nonsulfated disaccharide structures, respectively, at the nonreducing end of chondroitin sulfate chains, reacted with only 5/6/3-B-3. This result indicated that the chondroitin sulfate, isomer in the bone marrow is chondroitin 6- sulfate, consistent with the biochemical results. The chondroitin 6- sulfate was localized mainly in the extracellular compartment and was considered to be involved in construction of the hemopoietic microenvironment in the bone marrow.
