[Effect of moxibustion on immune function homeostasis in rats with diarrhea irritable bowel syndrome based on SCF/c-kit signaling pathway].

Objective: To observe the effects of moxibustion on the stem cell factor (SCF)/tyrosine kinase receptor (c-kit) signaling pathway and immune function in rats with diarrhea irritable bowel syndrome (IBS-D), and to explore the mechanism of moxibustion for IBS-D.

Methods: Among 52 young rats born from 6 healthy pregnant SPF rats, 12 rats were randomly selected into the normal group, and the remaining 40 rats were treated with the three-factor combination method of maternal separation, acetic acid enema and chronic restraint stress to establish the IBS-D rat model. Thirty-six rats with successful IBS-D model were randomly divided into a model group, a moxibustion group, and a medication group, 12 rats in each group. The rats in the moxibustion group were treated with suspension moxibustion at "Tianshu" (ST 25) and "Shangjuxu" (ST 37); the rats in the medication group were treated with intragastric administration of rifaximin suspension (150 mg/kg). All the treatments were given once a day for 7 consecutive days. The body mass, loose stool rate (LSR), the minimum volume threshold when abdominal withdrawal reflex (AWR) scored 3 were measured before acetic acid enema (35 days old), after modeling (45 days old), and after intervention (53 days old). After intervention (53 days old), HE staining was used to observe the morphology of colon tissue, and spleen and thymus coefficients were measured; ELISA method was used to detect serum inflammatory factors (tumor necrosis factor a [TNF-a], interleukin [IL]-10, IL-8), T-lymphocyte subsets (CD, CD, CD), value of CD/CD and immune globulin (IgA, IgG, IgM); real-time PCR method and Western blot method was used to detect the expression of SCF, c-kit mRNA and protein in colon tissue; immunofluorescence staining method were used to detect positive expression of SCF and c-kit.

Results: After intervention, compared with the normal group, in the model group, the body mass and the minimum volume threshold when AWR scored 3 were decreased (<0.01), LSR, spleen and thymus coefficients, serum levels of TNF-α, IL-8, CD, CD, CD/CD, IgA, IgG, IgM were increased (<0.01), serum IL-10 level and protein and mRNA expression of SCF and c-kit in colon tissue were decreased (<0.01), and the positive expression of SCF and c-kit was decreased (<0.01). Compared with the model group, in the moxibustion group and the medication group, the body mass and the minimum volume threshold when AWR scored 3 were increased (<0.01, <0.05), LSR, spleen and thymus coefficients, serum levels of TNF-α, IL-8, CD, CD, CD, CD/CD, IgA, IgG, IgM were decreased (<0.01, <0.05), serum IL-10 level and protein and mRNA expression of SCF and c-kit in colon tissue were increased (<0.01), and the positive expression of SCF and c-kit was increased (<0.01). Compared with the medication group, in the moxibustion group, the level of serum CD was decreased (<0.05), the value of CD/CD was increased (<0.01), and there was no significant difference in other indexes (>0.05). The expression of SCF and c-kit mRNA was positively correlated with the minimum volume threshold when AWR scored 3 and IL-10 (<0.01), and negatively correlated with remaining indexes (<0.01, <0.05).

Conclusion: Moxibustion could reduce visceral hypersensitivity, improve symptoms of abdominal pain and diarrhea in IBS-D rats, and its mechanism may be related to up-regulation of the expression of SCF/c-kit signaling pathway and improvement of IBS-D immune function.