Different effects of high molecular weight sodium hyaluronate and NSAID on the progression of the cartilage degeneration in rabbit OA model

Objective: We examined the effects of nonsteroidal anti-inflammatory drug (NSAID) and intra-articular injections of sodium hyaluronate (HA) on cartilage degeneration in rabbit knee osteoarthritis (OA) model induced by partial meniscectomy. Methods: Loxoprofen sodium (LOX) was used as the NSAID, administered p.o. once daily for 14 days at a dose of 4 mg/kg, starting from the day of meniscectomy. Suvenyl(R) (SVE) was used as the high molecular weight HA, injected intra-articularly into injured knee every 3 days from the day of surgery. The effect on pain was assessed by an Incapacitance Tester, and the damage of cartilage was evaluated by visual assessment and histopathology at 14 days after the surgery. Results: Hind paw weight bearing on the injured paw decreased time-dependently in the control group. In other three groups, the decrease of hind paw weight distribution was suppressed, demonstrating an analgesic effect. Visible damage and histopathological findings of cartilage degeneration were evident in the cartilages of the control group at day 14. In the SVE group, the damaged cartilage area decreased and cartilage degeneration was ameliorated. In contrast, in the LOX group, the cartilage degeneration was augmented compared with the control group. And, this exacerbated cartilage degeneration induced by LOX was reversed by the concomitant use of SVE. Conclusion: Our data show that the treatment with high molecular weight HA from earlier stage is strongly recommended to preserve the structure of cartilage. (C) 2006 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.