Wei-Tong-Xin decoction targets CD8+ T cell-driven colitis via gut microbiota and linoleic acid modulation: an...

Wei-Tong-Xin (WTX), derived from the Hua Tuo Zhong Cang Jing, has been demonstrated to exert therapeutic effects against gastric ulcers and gastritis, with well-established anti-inflammatory properties. However, its potential role in intestinal inflammation has not yet been investigated.

To evaluate the therapeutic efficacy of WTX in dextran sulfate sodium (DSS)-induced colitis in mice and to elucidate its underlying pharmacological mechanisms while identifying its active components.

Mice with DSS-induced colitis were treated with WTX extracts. The primary active fraction of WTX was identified by screening intestinal injury and hematological indicators. Integrated 16S rRNA sequencing, serum metabolomics, and network pharmacology analyses were employed to investigate the therapeutic mechanisms. Specifically, serum metabolomics identified linoleic acid (LA) metabolism as the major metabolic pathway regulated by the petroleum ether (PE) fraction, whereas network pharmacology linked PE-derived constituents to colitis-related targets and identified ALOX5 and PTGS2 as key nodes connecting PE with LA metabolism. These findings were subsequently validated using LA supplementation and pseudo-germ-free mouse models.

The PE fraction significantly alleviated colitis symptoms, including reduced disease activity index scores, attenuation of colon shortening, improved intestinal mucosal barrier integrity, and decreased CD8⁺ T-cell infiltration in the spleen, colon, and mesenteric lymph nodes. PE also reshaped the gut microbiota by modulating the abundance of Bacteroidota and Proteobacteria, reduced the levels of unsaturated fatty acids, particularly those involved in LA metabolism, and downregulated the expression of ALOX5 and PTGS2. Fecal microbiota transplantation produced comparable therapeutic effects, whereas LA supplementation reversed the protective effects of PE.

PE alleviates colitis by remodeling the gut microbiota, promoting the dominance of Bacteroidota, inhibiting LA metabolism through the ALOX5/PTGS2 pathway, and suppressing the activation of pathogenic CD8⁺ T cells. These effects collectively preserve intestinal barrier integrity and mitigate the progression of colitis.