The glycosaminoglycans in menisci in experimental and natural osteoarthritis

The glycosaminoglycans in the menisci of beagles 5--7 years old were analyzed at various times after osteoarthritis was induced by sectioning the anterior cruciate ligament of one knee; the unoperated knee served as control. In the first month after induction, there were signs of inflammation in the operated joint. After 1 week, the water content was elevated and the glycosaminoglycan content (per dry weight) was reduced. The content of keratan sulfate decreased more than that of chondroitin sulfate, but the hyaluronic acid content did not change consistently. The relative proportions of chondroitin-4-sulfate, chondroitin-6-sulfate, and dermatan sulfate remained unchanged. After 3--18 months, the glycosaminoglycan levels reverted to normal, and there was some evidence that after 15--18 months, they were elevated above normal. These results, together with results obtained from single examples of mild and severe osteoarthritis in working foxhounds, suggest that, in contrast to articular cartilage, the meniscus is capable of some regeneration in response to injury.