LONG-TERM EFFECTS OF HYALURONAN ON EXPERIMENTAL OSTEOARTHRITIS IN THERABBIT KNEE

Objective: Long-term assessment of the effect of hyaluronan (HA) on th e articular cartilage and synovium in an animal knee joint during the development of osteoarthritis (OA). Design: Sixty mature New Zealand w hite rabbits underwent unilateral anterior cruciate ligament transecti on (ACLT) and were divided into two groups. Group 1 (SA) received intr a-articular injections of 0.3 ml hyaluronan (HA) (i.e., ARTZ, MW: 8x10 (5)) beginning 4 weeks after ACLT, once a week for 5 weeks. Group 2 (S V) received injections of the vehicle (phosphate buffered saline) in t he same fashion as with the SA group. The contralateral nonoperated kn ee served as control. All animals were killed 21 weeks after surgery a nd their knee joints evaluated by gross morphologic, histologic, histo morphometric and biochemical analyses. Results: Gross morphological in spection indicated that the femoral condyles from the knees injected w ith vehicle suffered more severe cartilage damage than cartilage from the knees injected with HA. Furthermore, two out of three histomorphom etric parameters measured in the HA-treated cartilage (i.e., cartilage thickness and cartilage area which were not statistically different t han control) provided evidence showing a protective effect of HA on th e femoral condyles following ACLT. Biochemical analysis showed articul ar cartilage remaining on the femoral condyles following ACLT to have similar characteristics to contralateral controls. However, DNA concen tration in the synovium from the ACLT knees of the vehicle-treated ani mals was greater than contralateral control, while this parameter was not statistically different than contralateral control in the HA treat ed animals. Conclusions: These results demonstrate a protective effect of HA on preservation of the articulating surface of the femoral cond yle following ACLT up to 21 weeks post-surgery.