Effect of moxibustion on PI3K/Akt/mTOR signaling pathway in foot-pad synovium in rats with rheumatoid arthritis

Abstract

To observe the effect of moxibustion on phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin protein (PI3K/Akt/mTOR) signaling pathway in the foot-pad synovial tissue in rats with rheumatoid arthritis (RA), and to explore the mechanism of moxibustion for treating RA. Forty healthy SD rats were randomly divided into a control group, a model group, a moxibustion group, a cigarette-moxibustion group and a medication group, 8 rats in each group. The RA model was established with subcutaneous injection of complete Freund's adjuvant (CFA) in the left hind foot-pad under wind, cold and wet environment in the model group, the moxibustion group, the cigarette-moxibustion group and the medication group. The rats in the moxibustion group were treated with moxibustion at "Zusanli" (ST 36) for 20 min; the rats in the cigarette-moxibustion group were treated with moxibustion of ordinary cigarette at "Zusanli" (ST 36) for 20 min; the rats in the medication group were treated with tripterygium glycosides suspension (0.8 mg/100 g) by gavage. All the intervention was given once a day for 15 days. The left hind foot-pad volume was measured before and after modeling and after 15-day intervention. After 15-day intervention, the serum levels of IL-17 and IL-23 were detected by ELISA method, and the expression levels of PI3K, Akt and mTOR in synovial tissue of left hind foot-pad were detected by Western blot method. The volume of left hind foot-pad, the serum levels of IL-23 and IL-17 and the expression of PI3K, Akt and mTOR in synovial tissue of left hind foot-pad in the model group were higher than those in the control group (P<0.01). After intervention, the volume of left hind foot-pad and the expression of PI3K, Akt and mTOR protein in synovium tissue in the moxibustion group and medication group were lower than those in the model group (P<0.01, P<0.05), while the serum levels of IL-17 and IL-23 in the moxibustion group were lower than those in the model group (P<0.01). The volume of left hind foot-pad, the serum levels of IL-23 and the expression of mTOR protein in synovial tissue in the moxibustion group were lower than those in the medication group (P<0.01, P<0.05), while the volume of left hind foot-pad, the serum levels of IL-23 and the expression of PI3K, Akt and mTOR protein in synovium tissue in the moxibustion group were lower than those in the cigarette-moxibustion group (P<0.01). Moxibustion may play a therapeutic effect on RA by inhibiting the level of IL-23, IL-17 and the activity PI3K/Akt/mTOR, and regulating inflammatory response and autophagy.