BACKGROUND:Intraarticular hyaluronic acid (HA)has been used as one common method in the treatment of osteoarthritis. But its application in treating Kashin-Beck disease (KBD) is generalizing. The effect of HA on chondrocyte metabolism in KBD patients remains unclear.OBJECTIVE:To investigate the effects of HA on the synthesis of collagen Ⅱ and aggrecan in KBD chondrocytes cultured in vitro to understand its clinical treatment for KBD.DESIGN,TIME AND SETTING:Comparative observation. The experiment was performed in the Laboratory Center of Biomedicine and Endemic Disease Laboratory of College of Medicine,Xi'an Jiaotong University from September 2006 to January 2009.MATERIALS:Samples of KBD were from cartilage and corpus liberum excised from 6 KBD patients undergoing knee joint operation,and normal samples of fresh knee cartilages were provided by 6 people undergoing amputation or death by accident METHODS:Chondrocytes of KBD and normal control were separated and cultured in vitro. Varying dosages of HA (100,500 gm/L) were administered to normal and KBD chondrocytes cultured in vitro for 6 days. Negative control was not treated with HA.MAIN OUTCOME MEASURES:Effects of HA on collagen Ⅱ and aggrecan mRNA expression in KBD patients and normal people by RT-PCR.RESULTS:Compared with normal control group,the mRNA level of collagen Ⅱ and aggrecan were lower in KBD (P＜0.05).After administration of HA (100,500 mg/L) the mRNA level of collagen Ⅱ and aggrecan were significantly increased,and the effects of 500 mg/L was more significant.CONCLUSION:HA can increase the collagen Ⅱ and aggrecan mRNA level of KBD chondrocytes cultured in vitro. In particular,500 mg/L HA significantly promoted chondrocyte metabolism compared with 100 mg/L HA.