Therapeutic effect of Patrinia villosa on TNBS-induced ulcerative colitis via metabolism, vitamin D receptor and NF-κB signaling pathways

Ulcerative colitis (UC) is a chronic inflammatory disease affecting the colon. Patrinia villosa Juss. (P.V) is an important traditional Chinese medicine widely used for more than 2000 years from ShenNongBenCaoJing, a famous ancient Chinese medicinal literary. P.V is often used in the treatment of UC, but the pathogenesis is not clear. Aim of the study: This study was designed to analysis the metabolic pathways and relevant mechanisms of P.V on UC rats induced by TNBS. The rat model of UC was established by 2,4,6-trinitrobenzene sulfonic acid (TNBS)/ethanol method. Three doses of P.V (21 g/kg, 43 g/kg, 64 g/kg) were administrated for 14 days. Disease activity index (DAI) scoring system and H&E staining were used to evaluate the efficacy. A method for simultaneous detection of 96 endogenous metabolic components was established by UPLC-MS. The method was used to detect the metabolites in serum and liver of rats with UC induced by TNBS. PLS-DA and Metaboanalyst were used to analyze the main metabolic pathways involved in the treatment of UC. The contents of IL-1β, TNF-α and IL-6 in the colonic homogenate of rats were detected by enzyme-linked immunosorbent assay (ELISA). The expression levels of VDR, NF-κB, p-NF-κB, NLRP3 and caspase-1 in colon tissues of rats were detected by the method of Western blot. DAI scoring system and H&E staining indicated that P.V have the obvious therapeutic effect on UC induced by TNBS as a dosage-dependent manner. 36 potential biomarkers in serum and 26 potential biomarkers in liver were found in positive and negative ion mode of UPLC-MS, which significantly affected Glycine, serine and threonine metabolism, Glycerophospholipid metabolism, Purine metabolism, Histidine metabolism, Alanine, aspartate, and glutamate metabolism, Arginine and proline metabolism in serum, and significantly affected Purine metabolism, Lycine, serine and threonine metabolism, Glutathione metabolism, Glyoxylate and dicarboxylate metabolism in the liver. The contents of pro-inflammatory cytokines and receptors related to NF-κB signaling axis of model group were significantly higher than those of the control group, compared with the model group, their contents of the P.V group were significantly decreased (p < 0.01). Compared with the model group, the expression of NF-κB, p-NF-κB, NLRP3 and caspase-1 in colon tissues of the rats in P.V group were significantly decreased (p < 0.01). The expression of VDR in model group were significantly reduced compared to that in the control group, compared with the model group, the expression of VDR in P.V group were significantly increased (p < 0.01). P.V has an obvious therapeutic effect on UC induced by TNBS by regulating the energy metabolism, amino acid metabolism, purine metabolism, bile acid metabolism and lipid metabolism. P.V exerts anti-inflammatory effect by impacting bile acid levels, activating VDR, and inhibiting the overactivation of NF-κB signaling pathways.