Objective:The present study investigated how mild moxibustion treatment affects the intestinal micro-biome and expression of NLRP3-related immune factors in a rat model of intestinal mucositis(IM)induced with 5-fluorouracil(5-Fu).Methods:Forty male Sprague-Dawley rats were randomly divided into control,chemotherapy,moxibus-tion and probiotics groups.The IM rat model was established by intraperitoneal injection of 5-Fu.Mild moxibustion treatment and intragastric probiotic administration were provided once daily for 15 days.Tissue morphology,serum levels of inflammatory factors and the expression levels of tight junction pro-teins,caspase-1,gasdermin D and NLRP3 were evaluated in colon tissue,through hematoxylin and eosin staining,electron microscopy,enzyme-linked immunosorbent assay,Western blotting,quantitative real-time reverse transcription polymerase chain reaction and immunofluorescence.Gut microbiome profiling was conducted through 16S rRNA amplicon sequencing.Results:Moxibustion and probiotic treatments significantly increased the expression levels of tight junc-tion proteins,reduced cell apoptosis and the expression levels of caspase-1,gasdermin D and NLRP3;they also decreased the serum levels of tumor necrosis factor-α,interleukin(IL)-6,IL-1β and IL-18,while increasing serum levels of IL-10.Moxibustion and probiotic treatments also corrected the reduction inα-diversity and β-diversity in IM rats,greatly increased the proportion of the dominant bacterial genus Lactobacillus and reduced the abundance of the genera Roseburia and Escherichia in chemotherapy-treated rats to levels observed in healthy animals.We also found that these dominant genera were firmly correlated with the regulation of pyroptosis-associated proteins and inflammatory factors.Finally,mox-ibustion and probiotic treatments elicited similar effects in regulating intestinal host-microbial home-ostasis and the expression of NLRP3 inflammasome-related factors.Conclusion:Moxibustion exerts its therapeutic effect on IM by ameliorating mucosal damage and reduc-ing inflammation.Moreover,moxibustion modulates the gut microbiota,likely via decreasing the expres-sion levels of the NLRP3 inflammasome.