Abstract:

Objective To discuss the therapeutic effect of Saposhnikoviae Radix on rheumatoid arthritis and its effect on the nuclear factor-κB （NF-κB） signaling pathway，and to provide the basis for the treatment of rheumatoid arthritis. Methods Fifty rats were randomly divided into control group， model group， dexamethasone group， low dose of Saposhnikoviae Radix group， and high dose of Saposhnikoviae Radix group，and there were 10 rats in each group； except for control group， the rats in the other groups were given intradermal injection of type Ⅱ collagen at the root of the tail and left posterior foot to prepare the rheumatoid arthritis models； after the models were prepared successfully， the rats in dexamethasone group were given dexamethasone （2 mg·kg^－1），the rats in low and high doses of Saposhnikoviae Radix groups were given Saposhnikoviae Radix wild product （0.45 and 0.90 g·kg^－1）， and equal volume of normal saline was given to the rats in control group and model group.The arthritis index（AI） and foot swelling degrees of the rats in various groups were recorded， the organ coefficients of the rats in various groups were calculated； enzyme-linked immunosorben assay （ELISA） method was used to detect the levels of tumor necrosis factor-α （TNF-α）， interleukin-1β （IL-1β）， and interleukin-6 （IL-6） in serum of the rats in various groups， and the expression levels of NF-κB，NF-κB inhibitor α （IkB-α）， IκB-α kinase β （IKK-β）， cyclooxidase-2 （COX-2），and TNF-α proteins in synovial tissue of the rats in various groups were detected by Western blotting method. Results Compared with control group， the AI score and swelling degree of foot of the rats in model group were significantly decreased （P<0.01）， while the thymus index was significantly increased （P<0.01）； compared with model group， the AI score and swelling degree of foot of the rats in dexamethasone group and low and high doses of Saposhnikoviae Radix groups were significantly decreased （P<0.05 or P<0.01）， and the thymus indexes were significantly decreased（P<0.01）.The ELISA results showed that compared with control group，the levels of TNF-α， IL-1β，and IL-6 in serum of the rats in model group were increased（P<0.01）； compared with model group，the levels of TNF-α， IL-1β，and IL-6 in serum of the rats in dexamethasone group， low and high doses of Saposhnikoviae Radix groups were significantly decreased （P<0.01）.The HE staing results showed that the synovial tissue of the rats in control group was normal，and the synovial tissue of the rats in model group showed hyperplasia accompanied with extensive infiltration of inflammatory cells； compared with model group， the degrees of proliferation of synovial tissue and infiltration of inflammatory cells of the rats in dexamethasone group， low and high doses of Saposhnikoviae Radix groups were decreased.The Western blotting results showed that compared with control group， the expression levels of NF-κB，IKK-β，COX-2， and TNF-α proteins in synovial tissue of the rats in model group were increased （P<0.01），the expression level of IκB-α protein was decreased （P<0.01）；compared with model group， the expression levels of NF-κB，IKK-β，COX-2， and TNF-α proteins in synovial tissue of the rats in dexamethasone group， low and high doses of Saposhnikoviae Radix groups were decreased （P<0.01），the expression level of IκB-α protein was increased （P<0.01）. Conclusion Saposhnikoviae Radix wild product can improve the joint injury by reducing the levels of proinflammatory cytokines and inhibiting the excessive activation of NF-κB signaling pathway in synovial tissue， thus playing a therapeutic role in the rheumatoid arthritis.

Key words: Saposhnikoviae Radix wild product, Rheumatoid arthritis, Nuclear factor kappa-B, Dexamethasone, tumor necrosis factor-α