Effects of low-frequency ultrasound combined with Tongluo Zhitong herbs on urokinase-type plasminogen activator system and inflammatory cytokines in knee osteoarthritis / 中国组织工程研究

ABSTRACT

BACKGROUND: Low-frequency ultrasound combined with Tongluo Zhitong herbs can effectively relieve pain and improve joint function of patients with osteoarthritis, but the underlying mechanisms are still unclear.OBJECTIVE: To investigate the effects of low-frequency ultrasound combined with Tongluo Zhitong herbs on urokinase-type plasminogen activator (uPA) and inflammatory cytokines of osteoarthritis rabbits and the related mechanisms.METHODS: Forty rabbits were randomly divided into four groups normal, model, control, and experimental groups. The normal group was treated with normal feeding, not for any processing. For the other three groups, papain was injected into the rabbit knee articular cavity to establish osteoarthritis models. One week later, the experimental group was treated with low frequency ultrasound combined with Tongluo Zhitong herbs for 3 weeks, the control group treated with the same volume of normal saline, and the model group received no intervention. The levels of inflammatory cytokines in the serum and synovial fluid were measured, the histological changes of synovial tissues and articular cartilage were evaluated using Mankin's score, and the expression levels of uPA and its receptor were determined by western blot assay.RESULTS AND CONCLUSION: The levels of inflammatory cytokines in the model group were significantly higher than those in the normal and experimental groups (P 0.05). Compared with the model group, in the experimental group, the expression levels of uPA and its receptor were significantly downregulated,and the expression of uPA inhibitor was notably upregulated. These data show that low-frequency ultrasound combined with Tongluo Zhitong herbs attenuates inflammatory reaction in the synovial tissues, by inhibiting the formation of joint fluid and production of inflammatory cytokines, which is an effective treatment for knee osteoarthritis.