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.