Xihuang pill ameliorates colitis in mice by improving mucosal barrier injury and inhibiting inflammatory cell filtration through network regulation

Ethnopharmacological relevance: The prevalence of colitis is on the rise, and effective treatment options are currently lacking. Xihuang pill (XHP) is a traditional Chinese medicine formula mentioned in the "Volume 4 of Surgical Evidence and Treatment of the Whole Life" authored by the renowned doctor Hong-Xu Wang during the Qing Dynasty. It is now part of the "Volume 9 of Chinese medicine formula preparation in Drug Standard." XHP and its primary ingredients have been demonstrated anti-inflammatory properties against colitis. However, the specific effects and underlying mechanisms of XHP in treating colitis remain unknown. Aim of the study: This study aimed to investigate the potential impact of XHP on colitis and uncover the underlying mechanisms involved. Materials and methods: An acute colitis model was developed in C57BL/6N mice, and the effects on weight loss, colon length, the permeability of the colonic mucosa barrier, Claudin-5 and Occludin expression, number of both infiltrating MPO-positive cells and CD68-positive cells, and the content of pro-inflammatory cytokines (IL-6, IL22, IL-1 beta, and TNF-alpha) in the colon tissue were investigated. Low-, medium-, and high-dose XHP (0.45, 0.9, and 1.8 g/kg/day) (batch number: z21021222) were administered to the mice by gavage over the course of two weeks. Additionally, the protein expression levels in colon tissue from the control group, colitis group, and XHP low-dose administration group mice were analyzed by quantitative proteomics techniques. The comprehensive profiling and characterization of absorbed components in mice blood following oral administration of XHP were identified by HPLC/Q-TOF-MS techniques, and the absorbed components in blood were combined with proteomics to reveal the mechanism of enteritis inhibition by XHP. Results: Our findings indicated that XHP enhanced weight loss and colonic shortening of colitis mice. Additionally, XHP reduced the increase in permeability of the colonic mucosa barrier and decreased expression of Claudin-5 and Occludin, while significantly reducing the number of infiltrating MPO-positive cells and CD68positive cells in the colon tissue. We found that XHP reduced the production of pro-inflammatory cytokines, including IL-6, IL-22, IL-113, and TNF-alpha in colon tissue. Pharmacokinetic analysis suggested that XHP contained 24 blood-entering prototype ingredients, which improved colitis through the regulation of various proteins (e.g., Ctsb, Sting1, and Abat) linked to mucosal barrier injury and inflammation. Conclusion: XHP improved intestinal mucosal barrier injury and reduced MPO-positive cells and CD68-positive cell infiltration through multiple targets and pathways, providing support for XHP as a promising therapy for colitis.