Changes in the Sedimentation Profile of Proteoglycan Aggregates in Early Experimental Canine Osteoarthritis

Osteoarthritis was induced in 12 normal dogs by severing of the anterior cruciate ligament of the right knees, the left knees serving as sham operated controls. The animals were killed at 7 and 14 weeks postsurgery. The total hexuronate. and thus proteoglycan, content of the articular cartilage of operated knees remained unaltered during the period of study. After pretreatment with a highly purified collagenase and in the presence of selected protease inhibitors, a higher proportion of the tissue hexuronate could be extracted from the different topographical areas of osteoarthritic joints under non dissociative conditions (70-75% versus 55-65% for control knees). The nondissociatively recovered osteoarthritic proteoglycans (a-Al preparations) displayed progressive and consistent changes in their sedimentation profile. First, the size of the fast sedimenting or more saturated aggregates appeared to be reduced in the different regions of osteoarthritic joints at 7 weeks postoperatively. The disappearance of...