Hyaluronic acid in combination with chondroitin sulfate and hyaluronic acid improved the degeneration of synovium and cartilage equally in rabbits with osteoarthritis

The purpose of this study was to compare the chondroprotective effects of chondroitin sulfate (CS)-hyaluronic acid (HA) (CS-HA) injection and HA injection in an experimental model of osteoarthritis. After induction of osteoarthritis in rabbits, 28 rabbits were randomized into four groups: control group, 'HA' group, 'CS' group, and 'CS-HA' group. After 7 days, rabbits in the control group, 'HA' group, 'CS' group and 'CSHA' group were respectively treated with normal saline, HA, CS, or CS-HA injection in the knees. All animals were treated once weekly. The animals were treated continuously for 5 weeks. Histological and biochemical evaluations were performed. As shown by histological observation, CS-HA injection treatment showed a chondroprotective effect on osteoarthritis. However, the histological scores of 'HA' group and 'CS-HA' group were not significantly different (p > 0.05). The results of biochemical evaluation showed that the expression levels of IL-1 beta, TNF-alpha, TIMP-1 and NO in synovial fluid of treated groups were all different from the control group (p < 0.05). However, the expression levels of these biochemical molecules in three treated groups were not significantly different (p > 0.05). In conclusion, CS-HA injection showed no obvious advantage over HA injection in osteoarthritis treatment.