Chinese Medicine Enemas for Ulcerative Colitis: Mechanisms and Optimal Duration from a Systematic Review and...

This systematic review and meta-analysis aimed to elucidate the mechanisms underlying the efficacy of Chinese medicine enema formulations in animal models of ulcerative colitis (UC) and to provide a scientific basis for their potential clinical application. Comprehensive searches of PubMed, Web of Science, Cochrane Library, Elton B. Stephens Company (EBSCO), and ScienceDirect identified relevant animal studies published up to December 2024. Methodological quality was assessed using the SYRCLE risk of bias tool, and statistical analyses were conducted with RevMan 5.3 and Stata 15. Twenty studies comprising 980 animals were included, with quality scores ranging from 2 to 6. Chinese medicine enemas significantly reduced histological colitis score, disease activity index, spleen index, colon damage score, and inflammatory mediators including IL-6, TNF-α, IL-1β, IL-8, COX-2 mRNA, and myeloperoxidase. They also improved body weight change, colon length, intestinal tight junction proteins (ZO-1, Occludin), IL-10 expression, and regulatory T-cell levels (CD4⁺CD25⁺FOXP3⁺), while modulating gut microbiota composition, particularly Firmicutes and Bacteroides. These findings suggest that the therapeutic benefits of Chinese medicine enemas may derive from anti-inflammatory activity, enhancement of intestinal barrier integrity, and regulation of gut flora. However, substantial heterogeneity-likely due to differences in animal species, sex, and intervention duration-and generally low methodological quality limit the strength of the evidence. Further well-designed, high-quality preclinical and clinical studies are warranted to confirm efficacy, optimize treatment protocols, and evaluate safety for human application.