Objective To observe the effect of moxibustion on serum inflammatory factors

Toll-like receptor 4(TLR4)

myeloid differentiation factor 88(MyD88) and nuclear factor Kappa B(NF-κB) in colon tissue of rats with diarrhea-predominant irritable bowel syndrome(IBS-D)

so as to explore the mechanism of moxibustion in the treatment of IBS-D. Methods Healthy male SD rats were randomly divided into blank group

model group and moxibustion group

with 8 rats in each group. The IBS-D model was established by chronic restraint combined with gavage of Senna-leaf solution. The rats of the moxibustion group was treated with moxibustion at "Tianshu"(ST25)and "Shangjuxu"(ST37)for 30 min

once a day for 7 d. After the intervention

the rate of loose stools and the minimum threshold volume of abdominal withdrawal reflex(AWR) induced by colorectal distension were observed. The contents of serum inflammatory factors IL-1β

TNF-α and IL-6 were detected by ELISA. The pathological changes of rat colon were observed by H.E. staining. The average optical density of TLR4 and NF-κB(p65) in colon tissue was detected by immunohistochemistry. The relative expressions of TLR4

MyD88 and NF-κB(p65) mRNAs in colon tissues were detected by real-time fluorescence quantitative PCR

and the expression levels of TLR4

MyD88 and NF-κB(p65) proteins in colon tissues were detected by Western blot. Results There was a mild degree of inflammation in colon in rats of the model group. Compared with the blank group

the minimum volume threshold of AWR decreased significantly(P< 0.01)

and the rate of loose stools

the contents of IL-1β

IL-6 and TNF-α in serum as well as the expressions of TLR4

MyD88

NF-κB(p65) mRNAs and protein in colon tissues were significantly increased in the model group(P<0.01). Compared with the model group

the inflammation was alleviated in colonic mucosa

the minimum volume threshold of AWR increased significantly(P<0.01)

and rate of loose stools decreased significantly(P<0.01) in the moxibustion group

the contents of IL-1β

TNF-α and IL-6 in serum and the expression levels of TLR4

MyD88

NF-κB(p65) mRNAs and proteins in colon tissue decreased significantly in the moxibustion group(P<0.01). Conclusion Moxibustion ST25 and ST37 can improve diarrhea symptom and visceral hypersensitivity in IBS-D rats

which may be related with its effects in inhibiting TLR4/MyD88/NF-κB signaling pathway and reducing the expression of inflammatory factors.