Effect mechanism investigation of herb-partitioned moxibustion on relieving colon inflammation in Crohn disease rats based on neutrophil extracellular traps

Objective To explore the mechanism of herb-partitioned moxibustion in relieving rat intestinal inflammation by focusing on the neutrophil extracellular traps (NETs) in Crohn disease (CD) development. Methods Rats were randomly divided into a normal group, a model group, a herb-partitioned moxibustion group, and a mesalazine group. The CD rat model was prepared with 2,4,6-trinitrobenzene sulfonic acid except for rats in the normal group. Rats in the normal group and model group did not receive any treatment but had the same fixation as the other groups. Rats in the herb-partitioned moxibustion group received herb-partitioned moxibustion at Qihai (CV6) and bilateral Tianshu (ST25). Rats in the mesalazine group received intragastric administration of mesalazine enteric-coated tablets. The general situation of rats in each group was recorded, and the histopathological changes in the colon were observed and scored by hematoxylin-eosin staining. The serum concentrations of NETs DNA (NETs-DNA), neutrophil elastase (NE)-DNA, and myeloperoxidase (MPO)-DNA were detected by ABC enzyme-linked immunosorbent assay, and the citrullinated histone 3 (citH3), MPO, and NE protein and mRNA expression levels in rat colon tissue were observed by immunofluorescence and real-time quantitative polymerase chain reaction. Results Compared with the normal group, the mucosal ulcer reached the muscularis, the epithelium was incomplete, the goblet cells decreased obviously with significant inflammatory cell infiltration in the colon; the colonic mucosa damage index (CMDI) score increased significantly ( P <0.01); the serum NETs-DNA, NE-DNA, and MPO-DNA concentrations increased ( P <0.05); the NE, citH3, and MPO protein and mRNA expression in the colonic tissues increased significantly in the model group ( P <0.01 or P <0.05). Compared with the model group, the mucosal epithelium in the herb-partitioned moxibustion group and the mesalazine group was repaired and the goblet cells increased with a few infiltrating inflammatory cells in the colon; the CMDI score decreased ( P <0.01); the serum NETs-DNA, NE-DNA, and MPO-DNA concentrations decreased ( P <0.05); the NE, citH3, and MPO protein and mRNA expression in the colonic tissues was down-regulated ( P <0.01 or P <0.05). Conclusion Herb-partitioned moxibustion reduced the serum NETs complex and inhibited the protein and mRNA expression of NETs complex in the colon tissue, which may be one mechanism of herb-partitioned moxibustion in relieving colon mucosal inflammation in CD.