Rapid and sustained rise in the serum level of hyaluronan after anterior cruciate ligament transection in the dog knee joint.

OBJECTIVE: To monitor changes in serum levels of hyaluronan (HA) in experimental canine osteoarthritis (OA), and to relate these changes to the level of HA in synovial fluid (SF) and/or to the rate of HA synthesis by synovium.

METHODS: OA was induced in 16 dogs by anterior cruciate ligament transection; 7 dogs were sham operated. An immunoassay was used to measure HA levels in serum at various times postsurgery and in SF from OA knees at sacrifice (Week 13 postsurgery). The rate of HA synthesis by synovium from both knees of 9 OA dogs and 5 sham operated dogs was measured at 13 weeks.

RESULTS: The serum level of HA showed a minor transient rise postsurgery in sham operated dogs. In all OA dogs, this rise was marked and sustained and correlated with the SF level of HA. Further, in OA dogs, the rate of HA synthesis by synovium was elevated in both the operated OA knee and the nonoperated knee.

CONCLUSION: The sustained rise in the serum level of HA in OA dogs appears to be the result of increases in the rate of HA synthesis by synovium in both the operated and nonoperated knees, and possibly in other synovial joints.