ABSTRACT
ObjectiveBased on ultra performance liquid chromatography-quadrupole time-of-flight mass spectrometry （UPLC-Q-TOF/MS）， the changes of endogenous markers in rat plasma at the different stage， namely modeling and administration of Shenling Baizhusan （SLBZS）， and the mechanism of SLBZS in the treatment of ulcerative colitis （UC） were studied. MethodIn the modeling stage， rats were randomly divided into normal group， spleen deficiency with dampness retention-UC （SDDR-UC） and pure-UC （P-UC） model group. In the administration stage， SLBZS was given to the above two different model groups. After modeling and administration， rat plasma was collected and determined by UPLC-Q-TOF/MS. The mobile phase was 0.1% formic acid aqueous solution （A）-acetonitrile （B） for gradient elution （in positive ion mode：0-2 min， 99%A； 2-9 min， 99%-73%A； 9-10 min， 73%-44%A； 10-13 min， 44%-38%A； 13-19 min， 38%-28%A； 19-21 min， 28%-2%A； 21-23 min， 2%A； 23-25 min， 2%-10%A； 25-27 min， 10%-99%A； in negative ion mode：0-2 min， 85%A； 2-3 min， 85%-65%A； 3-5.5 min， 65%-44%A； 5.5-8 min， 44%-25%A； 8-10 min， 25%-2%A； 10-16 min， 2%-85%A）. The electrospray ionization （ESI） temperature was 120 ℃ under the positive and negative ion modes， and the acquisition range was 50-1 000. Partial least squares-discriminant analysis （PLS-DA） was used to analyze the changes of endogenous metabolites in the above two different model rats from the different stage. MetaboAnalyst 5.0 was used to analyze the metabolic pathways of these identified metabolites. ResultSixteen potential biomarkers were screened and identified in the modeling stage， among which 11 potential biomarkers were common in the two model rats， which mainly affected the primary bile acid biosynthesis pathway. Twenty-three potential biomarkers were screened and identified during the administration stage， among which 3 potential biomarkers were shared by the two model rats， and SDDR-UC and P-UC model rats had 11 and 9 potential biomarkers， respectively. It mainly affected 6 pathways such as purine metabolism， pentose phosphate pathway， pyrimidine metabolism， retinol metabolism， primary bile acid biosynthesis and steroid hormone synthesis. ConclusionThe primary bile acid biosynthesis pathway appears in the different stage of modeling and administration of UC， showing a dynamic change process. The therapeutic effect of SLBZS on SDDR-UC rats may be related to inhibiting the expression of nuclear transcription factor -κB （NF-κB） signaling pathway， activating farnesoid X receptor （FXR） and enhancing the expression of cytochrome P450.
