Moxibustion of Zusanli (ST36) and Shenshu (BL23) alleviates the inflammation of rheumatoid arthritis in rats through regulating macrophage migration inhibitory factor/glucocorticoids signaling

OBJECTIVE

To test the hypothesis that moxibustion may inhibit rheumatoid arthritis (RA) synovial inflammation by regulating the expression of macrophage migration inhibitory factor (MIF)/glucocorticoids (GCs).

METHODS

Fifty male Sprague-Dawley rats were randomly divided into five groups (n = 10 each): blank Control (CON) group, RA Model (RA) group, Moxibustion (MOX) group, MIF inhibitor (S,R)-3-(4-hydroxyphenyl)-4,5-dihydro-5-isoxazole acetic acid methyl ester (ISO-1) group, and Moxibustion + MIF inhibitor ISO-1 (MOX + ISO-1) group. Rats in the ISO-1 group and ISO-1 + MOX group were intraperitoneally injected with the inhibitor ISO-1. The rats in the RA group, ISO-1 group, MOX group, and ISO-1 + MOX group were injected with Freund's complete adjuvant (FCA) in the right hind footpad to establish an experimental RA rat model. In the MOX group and MOX + ISO-1 group, rats were treated with Moxa. The thickness of the footpads of the rats in each group was measured at three-time points before, after modeling and after moxibustion treatment. The contents of serum MIF, corticosterone (CORT), tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were detected by enzyme-linked immunosorbent assay; and the contents of synovial MIF were detected by Western blot. Hematoxylin-eosin (HE) staining method was used to observe the pathological changes of synovial tissue under a section light microscope, and pathological scoring was performed according to the grading standard of the degree of synovial tissue disease.

RESULTS

Moxibustion was found to reduce the level of MIF and alleviate inflammation in RA rats in this study. In addition, after inhibiting the expression of MIF, the level of CORT increased, and the level of TNF-α decreased. Treating RA rats with inhibited MIF by moxibustion, the level of CORT was almost unchanged, but the level of TNF-α further decreased. The correlation analysis data suggested that MIF was positively related to the expression of TNF-α and negatively correlated with the expression of CORT.

CONCLUSION

Reducing MIF to increase CORT and decrease TNF-α by moxibustion treatment in RA. MIF may be a factor for moxibustion to regulate the expression of CORT, but the expression of TNF-α is due to the incomplete regulation of the MIF. This study added to the body of evidence pointing to moxibustion's anti-inflammatory mechanism in the treatment of RA.

Efficacy of Moxa-burning heat stimulating Zusanli (ST36) and Shenshu (BL23) on expressions of macrophage migration inhibitory factor and macrophage apoptosis in rabbits with adjuvant-induced arthritis

OBJECTIVE

To evaluate the effects of moxa-burning heat stimulating acupoints Zusanli (ST36) and Shenshu (BL23) on macrophage migration inhibitory factor (MIF) and its related molecules which can provide scientific experimental basis for the clinical application of moxibustion treatment of rheumatoid arthritis (RA).

METHODS

Thirty rabbits were randomly assigned to control group, RA model (established by injecting Freund's Complete Adjuvant) group (RA group) and RA model with moxibustion group [Moxa group, Zusanli (ST36) and Shenshu (BL23), 5 moxa pillars/day, 6 d × 3]. The expressions of MIF mRNA were evaluated with reverse transcription polymerase chain reaction; the apoptosis rates of macrophages were detected by erminal deoxynucleotidyl transferase-mediated dTUP nick end labeling; the expressions of related signal molecules were detected with immunohistochemical S-P method and the levels of IL-2 were detected with enzyme-linked immunosorbent assay.

RESULTS

The expressions of MIF mRNA, extracellular regulated protein kinases 2, p38 mitogen-activated protein kinase and nuclear factor-κ-gene binding p65 in synovial tissue of RA group were significantly increased when compared with control group, which were lower remarkably in moxa group than those in RA group. The apoptosis rates of macrophages in RA group were significantly down-regulated as compared with the control group, which were up-regulated in moxa group compared with the RA group. The levels of IL-2 in synovial fluid from the RA group were elevated significantly as compared with that from control group, but those of the moxa group were reduced when compared with those from RA group.

CONCLUSIONS

Moxibustion may simultaneously regulate the expressions of MIF and its related signaling pathways molecules, the apoptosis rate of macrophages in synovial tissue, as well as the level of inflammatory factors in synovial fluid. The results suggest that the anti-inflammatory effect of moxibustion on RA may be related to inhibit the expression of MIF in synovial tissue, the molecules of some related signaling pathways and promote the apoptosis of macrophage.