Articular cartilage proteoglycans from normal and osteoarthritic mice

Articular cartilage proteoglycans from an osteoarthritic mouse strain, STR/IN, were labeled in vivo with 35S-sulfate and characterized with respect to extractability, ability to aggregate, size of monomer and glycosaminoglycan chains, sulfation of glycosaminoglycans, relative amounts of chondroitin-4 sulfate and chondroitin-6 sulfate, and link proteins. The proportion of 35S-labeled proteoglycans extractable by 0.4M guanidine hydrochloride was the same in control and osteoarthritic animals. However, a greater proportion was extractable by 4M guanidine hydrochloride in the STR/IN animals as compared with the control mice. The ability of the 35S-proteoglycans to aggregate was comparable in controls and osteoarthritic mice, as judged by their exclusion on Sepharose CL-2B. Monomers from both controls and osteoarthritic animals eluted from Sepharose CL-2B with a KAV of 0.47. Glycosaminoglycans from control and osteoarthritic animals eluted from Sepharose CL-6B with a KAV of 0.63, and no differences in sulfation or chondroitin-4 sulfate content were found. Aggregates were immunoprecipitated with link protein-specific antiserum, and only link protein 2 was found in aggregates from control and osteoarthritic animals.