[Effect of internal heat-type acupuncture needle on the expression of osteoprotegerin, receptor activator of NF-κB ligand and receptor activator of NF-κB of subchondral bone in knee osteoarthritis rabbits].

Objective: To investigate the effect of internal heat-type acupuncture needle on the expression of osteoprotegerin (OPG), receptor activator of NF-κB ligand (RANKL), and receptor activator of NF-κB (RANK) in knee osteoarthritis (KOA) rabbits, so as to explore its mechanisms in relieving KOA.

Methods: Thirty New Zealand rabbits were randomly divided into control, model and treatment groups, with 10 rabbits in each group. The KOA model was established by using Hulth method. The rabbits of the treatment group received internal heat-type acupuncture needles (42 ℃) on the left hind limb 20 min, once a week for 4 weeks. The behavioral scores were assessed according to the pain severity, gait, joint motion range and articular swelling severity in reference to the modified Lequesne's methods. Toluidine Blue staining was performed to observe the structure of the subchondral bone and to analyze the difference of morphometric parameters. The protein and mRNA expressions of OPG, RANKL and RANK were detected by Western blot and real-time PCR, respectively.

Results: Compared with the control group, the Lequesne total score, the separation degree of trabecular bone, the protein and mRNA expressions of RANKL and RANK in subchondral bone tissues were significantly increased in the model group, while the percentage of trabecular bone area, number of trabecular bone, the expression of OPG protein and mRNA were decreased (<0.05, <0.01). The above indexes were all reversed in the treatment group relevant to those of the model group (<0.05).

Conclusion: The internal heat-type acupuncture needle therapy can improve the motor function of rabbits with KOA, which may be related to its effects in up-regulating the expression of OPG and down-regulating the RANKL and RANK in subchondral bone tissue.