| Objective To observe the effect of sodium hyaluronate on both articular cartilage and the subchondral bone of osteoarthritis models in ovariectomized rats. Methods Thirty female SD rats aged of 3 months were randomly divided into 3 groups, sham-operated group, ovariectomized rats with bilateral anterior cruciate ligament transection (OVX-ACLT group), ovariectomized rats with bilateral anterior cruciate ligament transection + intra-articular injection of sodium hyaluronate (treatment group), with 10 rats in each group. Rats in the sham-operation group received no treatment. Rats in OVX-ACLT group and treatment group were ovariectomized and their anterior cruciate ligament of knee joint were transected. Two weeks after OVX-ACLT, rats in the treatment group received intra-articular injection of sodium hyaluronate, 50μg once a week for 12 weeks. Rats in the OVX-ACLT group were injected with normal saline. The rats were sacrificed after 12 weeks of treatment. The serum levels of C-terminal telopeptides of type I collagen (CTX-I), tartrate resistant acid phosphatase 5b (TRACP5b), and bone alkaline phosphatase (BALP) were detected. Mankin scores of articular cartilage were also evaluated. bone mass of subchondral bone was analyzed with micro-CT. Results ①The serum contents of CTX-I, TRACP5b, and BALP in OVX-ACLT group were significantly higher than those in sham operation group (P<0.01, P<0.05, and P<0.05), while those in treatment group were significantly lower than in OVX-ACLT group (P<0.05, P<0.05, P<0.05). ②Comparison of Mankin scores among the three groups: the scores in OVX-ACLT group were significantly higher than in sham operation group (P<0.01), and the scores in treatment group were significantly lower than in OVX-ACLT group (P<0.01). ③The bone volume fraction and trabecular bone numbers in OVX-ACLT group were significantly lower than those in sham-operated group (P<0.01, P<0.01), but the degree of bone trabecular separation was significantly higher than that in sham-operated group (P<0.01). The trabecular thickness was not statistically different between the two groups (P>0.05). The bone volume fraction and trabecular bone number in treatment group were significantly higher than those in OVX-ACLT group (P<0.01, P<0.01), but the degree of bone trabecular separation was significantly lower than that in OVX-ACLT group (P<0.01). The trabecular thickness was not statistically difference between the two groups (P>0.05). Conclusion Sodium hyaluronate releases osteoporosis and maintains the strength in the subchondral bone. It provides biomechanical support for the articular cartilage, and reduces the abnormal stress absorption of the cartilage, and delays the degeneration of the articular cartilage. |