Objective: To observe the effects of moxibustion on serum levels of interleukin (IL)-6, IL-8 and tumor necrosis factor-alpha (TNF-alpha), and to explore the effects of moxibustion on inflammatory damaging factors in experimental rheumatoid arthritis (RA) model rats; the relationship between the therapeutic effect of moxibustion on RA and the change in the Toll-like receptor (TLR) signaling pathway was analyzed using Toll-like receptor 4 (TLR4) antagonists and agonists. Methods: Fifty Sprague-Dawley (SD) rats were divided into a normal group, a model group, a moxibustion group, a moxibustion plus TLR4 agonist group (agonist group) and a moxibustion plus TLR4 antagonist group (antagonist group) according to the random number table, with 10 rats in each group. Except the normal group, rats in the other four groups were subjected to model preparation with the wind, cold and wet environmental factors plus Freund's complete adjuvant (FCA). Rats in the normal and model groups were not treated; rats in the moxibustion, agonist and antagonist groups started to be treated with the moxibustion (cigarette-type moxa) at bilateral Shenshu (BL 23) and Zusanli (ST 36) from the 4th day after the successful modeling, for 20 min each time with a total of 10 d. Rats in the agonist and the antagonist groups were injected with TLR4 agonist or antagonist [0.1 mg/(kg center dot bw)] via the tail vein 30 min before moxibustion. The concentrations of serum IL-6, IL-8 and TNF-alpha in each group were determined by enzyme-linked immunosorbent assay (ELISA). Results: Compared with the normal group, in the model group, the rat's right hind paw swelling was significantly obvious (P<0.01), there was a lot of inflammatory infiltration in the synovial tissues, the surface of the synovial membrane was unsmooth, the synovial membrane was hyperplasia and thicker, and the serum IL-6, IL-8 and TNF-alpha concentrations increased significantly (P<0.05). Compared with the model group, the paw swelling degrees of the rats in the moxibustion, the agonist and the antagonist groups reduced significantly (all P<0.01); the swelling degree in the antagonist group was milder than that in the agonist group, but the between-group difference was not statistically significant (P>0.05); inflammatory infiltration and synovial membrane hyperplasia in the synovial tissues of the moxibustion group and the antagonist group were all relieved differently; the decrease of synovial layer number in the moxibustion group was more obvious, and there were no obvious improvements in inflammatory infiltration and synovial thickness in the agonist group; the concentrations of IL-6, IL-8 and TNF-alpha in the moxibustion group were decreased, and the differences in the IL-6 and TNF-alpha concentrations were statistically significant (all P<0.01); there was no significant between-group difference in the IL-8 concentration (P>0.05); the concentrations of serum IL-8 and TNF-alpha in the agonist group increased significantly (both P<0.01), while the IL-6 concentration decreased without significant difference (P>0.05); the concentrations of IL-6 and IL-8 in the antagonist group decreased but the between-group differences were statistically insignificant (both P>0.05), and the TNF-alpha concentration significantly increased (P<0.05). Compared with the moxibustion group, IL-6, IL-8 and TNF-alpha concentrations increased in the agonist group, and the differences in the IL-8 and TNF-alpha concentrations were statistically significant (both P<0. 01); the concentrations of IL-6, IL-8 and TNF-alpha increased in the antagonist group, and the differences in the IL-6 and TNF-alpha concentrations were statistically significant (both P<0.01); there was no significant difference in the IL-8 concentration between the groups (P>0.05). The serum levels of IL-6, IL-8 and TNF-alpha in the antagonist group were lower than those in the agonist group (all P<0.05). Conclusion: Moxibustion at Shenshu (BL 23) and Zusanli (ST 36) can reduce the joint swelling degree and inflammation in synovial tissue of RA model rats, decrease the serum levels of IL-6, IL-8 and TNF-alpha in RA model rats; the decreases of IL-6 and TNF-alpha are more significant than the decrease of IL-8; TLR4 agonist and antagonist can significantly attenuate the effect of moxibustion in inhibiting releases of IL-6, IL-8 and TNF-alpha, so that the change in TLR signaling pathway affects the effect of moxibustion in inhibiting the releases of IL-6, IL-8 and TNF-alpha.
