Exploration on effect mechanism of Miao medicinal acupuncture therapy in treatment of knee osteoarthritis based on TRPV ion channel

Abstract

To observe the effect of Miao medicinal acupuncture therapy on transient receptor potential vanilloid (TRPV) channel in knee joint synovial tissue of the rabbits with knee osteoarthritis (KOA) model and to explore the mechanism of Miao medicinal acupuncture therapy in treatment of KOA. Of 34 New Zealand male rabbits, 6 rabbits were selected randomly as the normal group. KOA model was established in the rest rabbits by injecting a mixture of papain and L-cysteine in right knee joints. The 24 successfully modeled rabbits were randomized into a model group, a Miao medicinal acupuncture therapy group, a dermal needle group and a smearing group, 6 rabbits in each one. In the Miao medicinal acupuncture therapy group, Miao medicinal acupuncture therapy was adopted, in which, the roller type of dermal needle was used on the surface of right knee joint [a rectangle shape formed by "Xuehai" (SP 10), "Liangqiu" (ST 34), "Yanglingquan" (GB 34) and "Yinlingquan" (SP 9)], rolling in a "" shape, on which, Miao medicinal solution was smeared in advance. In the dermal needle group, the rolling stimulation was exerted on the right the right knee joint surface with the roller type of dermal needle. In the smearing group, Miao medicinal solution was smeared on the right knee joint surface. The intervention was given once every two days, 3 times weekly and the intervention was exerted consecutively for 4 weeks. Successively, on day 1, 21, 28, 35, 42 and 49 of experiment, paw withdrawal threshold (von Frey threshold) after mechanical stimulation was detected in the rabbits. HE staining was adopted to observe the histomorphological changes of the right knee joint cartilage in the rabbits. ELISA was used to determine the contents of interleukin-1 (IL-1β) and tumor necrosis factor-α (TNF-α) in the right knee synovial fluid. Western blot method and real-time PCR were used to determine the relative expressions of protein and mRNA of TRPV1 and TRPV4 in knee synovial tissue of the rabbits. Compared with the normal group, on day 49 of experiment, von Frey threshold was reduced significantly in the rabbits of the model group (P<0.01), the integrety of cartilage surface of knee joint was seriously damaged, the structural layers were disordered, the chondrocytes were clustered, the tide lines were distorted and the matrix staining disappeared. The contents of IL-1β and TNF-α of the right knee synovial fluid were increased significantly (P<0.01), and the relative expressions of protein and mRNA of TRPV1 and TRPV4 in the synovial tissue of the right knee were increased significantly (P<0.01). Compared with the model group, on day 49 of experiment, von Frey threshold was increased significantly in each of the Miao medicinal acupuncture therapy group, the dermal needle group and the smearing group (P<0.01). The right knee joint cartilage was complete in morphology, the structure clear was in layer, the cells were arranged in order and the matrix staining was uniform. The contents of IL-1β and TNF-α of the right knee synovial fluid were reduced significantly (P<0.01, P<0.05), and the relative expressions of protein and mRNA of TRPV1 and TRPV4 in the synovial tissue of the right knee were reduced significantly (P<0.01). Compared with either the dermal needle group or the smearing group, on day 49 of experiment, von Frey threshold was increased significantly in the Miao medicinal acupuncture therapy group (P<0.01). The right knee joint cartilage surface was even, the structure layers were clear. The contents of IL-1β and TNF-α of the right knee synovial fluid were reduced significantly (P<0.05), and the relative expressions of protein of TRPV1 and TRPV4 in the synovial tissue were reduced (P<0.01, P<0.05). Compared with the smearing group, the relative expression of TRPV1 mRNA in the synovial tissue was reduced significantly in the Miao medicinal acupuncture therapy group (P<0.05). Miao medicinal acupuncture therapy plays a role in treatment of KOA probably through inhibiting the expressions of IL-1β and TNF-α of knee synovial fluid and down-regulating the expressions of protein and mRNA of TRPV1 and TRPV4 in knee synovial tissue.