Matagenomic analysis of Tongxie Yaofang in treating rat model of ulcerative colitis with the "liver depression and spleen deficiency" syndrome

Tongxie Yaofang (TXYF), a classical traditional Chinese medicine, had therapeutic effect on the ulcerative colitis (UC) with liver depression and spleen deficiency syndrome. However, the exact mechanism of TXYF against UC remains unclear, especially for gut microbiota. This study aimed to investigate the changes in gut microbiota of UC rats treated with TXYF. Forty-eight Wistar rats were randomly divided into three groups: Control, Dinitrobenzene sulfonic acid (DNBS)-colitis, and DNBS+TXYF (n = 16). UC model was constructed via intrarectally injection of DNBS (25 mg DNBS and 50% ethanol 0.25 ml), and UC rats in the TXYF treatment group were given TXYF (20.8g/kg) by gavage for 21 days. The physiological indexes of rats were detected. Five samples from each group were selected for metagenomic analysis. TXYF treatment significantly reduced disease activity index (DAI) and colon mucosal damage index (CMID) scores, as well as decreased tumor necrosis factor-alpha level in UC rats. Metagenomic analysis showed that TXYF treatment prevented DNBS-induced dysregulation of gut microbial communities at the taxonomic levels. Compared with DNBS-colitis group, TXYF therapy significantly increased the abundance of Firmicutes, while reduced the abundance of Bacteroidetes and Proteobacteria to a normal level. Further, pathway analysis indicated that the relative abundance of the protein processing in endoplasmic reticulum pathway was mainly enriched in the DNBS-colitis group, whereas the abundance of this pathway was decreased in the DNBS+TXYF group. TXYF treatment could effectively regulate the dysregulation of intestinal flora in UC.