Metabolomics of interventional effects of Coptidis Rhizoma and its processed products on oral ulcer due to excess heat in rats

Abstract

Ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry(UPLC-Q/TOF-MS) was employed to examine the impact of Coptidis Rhizoma(CR) and its processed products on the metabolism in the rat model of oral ulcer due to excess heat and to compare the effectiveness of CR and its three products. Male SD rats were randomly allocated to the sham-operation(Sham), model(M, oral ulcer due to excess heat), CR, wine/Zingiberis Rhizoma Recens/Euodiae Fructus processed CR(wCR/zCR/eCR), and Huanglian Shangqing Tablets(HST) groups. Except the Sham group, the other groups were administrated with Codonopsis Radix-Astragali Radix decoction by gavage for two consecutive weeks. The anal temperature and water consumption of rats were monitored throughout the modeling period of excess heat. Following the completion of the modeling, oral ulcer was modeled with acetic acid. Hematoxylin-eosin(HE) staining was employed to observe the mucosal pathological changes in oral ulcer. A colorimetric assay was employed to determine the serum level of glutathione peroxidase(GSH-Px). Enzyme-linked immunosorbent assay(ELISA) was conducted to determine the levels of tumor necrosis factor-alpha(TNF-α), interleukin-6(IL-6), interleukin-1β(IL-1β), superoxide dismutase(SOD), and malondialdehyde(MDA) in the serum. The non-targeted metabolomics analysis based on UPLC-Q/TOF-MS was conducted on the serum samples. Metabolic profiles were then built, and the potential biomarkers were screened by principal component analysis(PCA) and orthogonal partial least squares discriminant analysis(OPLS-DA). The Mev software was used to establish a heat map and conduct cluster analysis on the quantitative results of the markers. The online databases including MBRole, KEGG, and MetaboAnalyst were used for pathway enrichment analysis and metabolic network building. The experimental results showed that the modeling led to pathological damage to the oral mucosa, elevated serum levels of TNF-α, IL-6, IL-1β, and MDA, and lowered levels of SOD and GSH-Px in rats. The drug administration recovered all the indices to varying extents, and wCR exhibited the best performance. Non-targeted metabolomics identified 48 differential metabolites including 27 metabolites in the positive ion mode and 21 metabolites in the negative ion mode. Five enriched pathways were common, including glycerophospholipid metabolism, linoleic acid metabolism, and tyrosine metabolism. Conclusively, CR and its three processed products could alleviate the inflammation and oxidative stress injury in rats suffering from oral ulcers due to excess heat by regulating lipid and amino acid metabolism. Notably, wCR demonstrated the most significant therapeutic effect.