Moxibustion with seed-size moxa cones alleviates colonic injury in mice with ulcerative colitis by regulating TLR4/MyD88/NF-κB signaling pathway

Abstract

Objectives: To observe the effect of moxibustion with seed-size moxa cones on the Toll-like receptor 4(TLR4)/myeloid differentiation factor 88(MyD88)/nuclear transcription factor-κB(NF-κB) signaling pathway in mice with ulcerative colitis(UC), so as to explore the therapeutic mechanism of moxibustion with seed-size moxa cones on colonic injury in UC.

Methods: Forty male C57BL/6 mice were randomly divided into blank group, model group, moxibustion group, and western medicine group, with 10 mice in each group. The UC mouse model was established by 3% DSS solution by free drinking for 7 consecutive days. Mice in the moxibustion group were treated with seed-size moxa cones at "Zhongwan"(CV12), "Tianshu"(ST25) and "Shangjuxu"(ST37), 3 moxa cones per point, with each cone applied for approximately 30 s, while mice in the western medicine group were orally administered with 300 mg/kg mesalazine solution, which were both conducted once a day for 7 consecutive days. The general condition of mice was observed every 2 days, and the disease activity index (DAI) score was calculated. HE staining was used to observe the morphology of colonic tissue in mice. ELISA was used to detect the serum interleukin(IL)-1β, tumor necrosis factor(TNF)-α, IL-6, and IL-8 contents. Immunohistochemistry was used to detect the positive expression of TLR4 and MyD88 in colonic tissue of mice. Real-time fluorescence quantitative PCR was used to detect the expression levels of TLR4, MyD88, and NF-κB p65 mRNAs in colonic tissue.

Results: Compared with the blank group, varying degrees of soft or watery stools were observed, colon length and body weight were decreased(P<0.01) in mice of the model group, while DAI score, colon weight index, mucosal damage score, colonic pathological score, serum IL-1β, TNF-α, IL-6, and IL-8 contents, positive expressions of TLR4 and MyD88, and TLR4, MyD88, and NF-κB p65 mRNA expressions in colonic tissue were increased(P<0.01). Compared with the model group, improved fecal characteristics were observed, colon length and body weight were increased(P<0.01) in mice of the moxibustion group and western medicine group, while DAI scores, colon weight indexes, mucosal damage scores, colonic pathological score, serum contents of IL-1β, TNF-α, IL-6, and IL-8, positive expressions of TLR4 and MyD88, and TLR4, MyD88, and NF-κB p65 mRNA expressions in colonic tissue were decreased(P<0.01, P<0.05). There was no significant difference in the above indicators between the moxibustion group and the western medicine group.

Conclusions: Moxibustion with seed-size moxa cones may alleviate colonic injury in UC mice by regulating the TLR4/MyD88/NF-κB signaling pathway and reducing the release of inflammatory factors.

Keywords: Colonic injury; Inflammatory response; Moxibustion with seed-size moxa cones; TLR4/MyD88/NF-κB signaling pathway; Ulcerative colitis.