Mycolic acids (MAs), i.e. 2-alkyl, 3-hydroxy long-chain fatty acids, are the hallmark of the cell envelope of Mycobacterium tuberculosis and are related with antibiotic resistance and host immune escape. Nowadays, they've become hot target of new anti-tuberculosis drugs. There are two main methods to detect MAs, ¹⁴C metabolic labeling thin-layer chromatography (TLC) and liquid chromatograph mass spectrometer (LC-MS). However, the user qualification of ¹⁴C or the lack of standards for LC-MS hampered the easy use of this method. TLC is a common way to analyze chemical substance and can be used to analyze MAs. In this study, we used tetrabutylammonium hydroxide and methyl iodide to hydrolyze and formylate MAs from mycobacterium cell wall. Subsequently, we used diethyl ether to extract methyl mycolate. By this method, we can easily extract and analyze MA in regular biological labs. The results demonstrated that this method could be used to compare MAs of different mycobacterium in different growth phases, MAs of mycobacteria treated by anti-tuberculosis drugs or MAs of mycobacterium mutants. Therefore, we can use this method as an initial validation for the changes of MAs in researches such as new drug screening without using radioisotope or when the standards are not available.
Mycolic Acids/metabolism* ; Chromatography, Thin Layer ; Mycobacterium tuberculosis ; Fatty Acids ; Antitubercular Agents/pharmacology*

ObjectiveTo investigate the effect of Shaoyaotang on T helper cell 17/regulatory T lymphocyte（Th17/Treg） cell balance in ulcerative colitis and decipher the intervention mechanism based on glucose metabolism reprogramming. MethodsThe mouse model of ulcerative colitis was established by the dextran sulfate sodium （DSS） method. Forty-eight C57BL/6 mice were randomly allocated into normal， model， Western drug control （mesalazine， 0.39 g·kg^-1·d^-1）， Shaoyaotang （15.54 g·kg^-1·d^-1）， inhibitor （2-deoxy-D-glucose， 2-DG， 100 mg·kg^-1·d^-1）， and inhibitor （2-DG， 100 mg·kg^-1·d^-1） + Shaoyaotang （15.54 g·kg^-1·d^-1） groups. Mice were administrated with the corresponding drugs by gavage for 7 days. The general conditions and the colon injury degree were observed 24 h after the last administration. The expression of interleukin （IL）-10 and IL-17 in the colon tissue was detected by immunohistochemical staining. Western blot and Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） were performed to determine the protein and mRNA levels， respectively， of hypoxia-inducing factor-1α （HIF-1α）， lactate dehydrogenase （LDHA）， and hexokinase 2 （HK2） in the colon tissue. Th17/Treg cell differentiation was detected by flow cytometry. Enzyme-linked immunosorbent assay was employed to measure the levels of lactic acid and glucose in the colon tissue and IL-10， IL-17， and IL-6 in the serum. ResultsCompared with the normal group， the model group showed decreases in body weight and disease activity index （DAI） （P<0.05）， elevations in levels of HIF-1α， LDHA， HK2， IL-17， IL-6， Th17 cells， lactic acid， and glucose in the colon tissue （P<0.05）， and declines in the levels of of IL-10 and Treg cells （P<0.05）. Compared with the model group， the drug administration groups showed increases in body weight and DAI （P<0.05）， declines in levels of HIF-1α， LDHA， HK2， IL-17， IL-6， Th17 cells， lactic acid， and glucose in the colon tissue （P<0.05）， and rises in levels of IL-10 and Treg cells （P<0.05）. Shaoyaotang+2-DG group had the most obvious effect. ConclusionShaoyaotang can relieve diarrhea and bloody stool in mice with ulcerative colitis by restoring the Th17/Treg cell balance via regulation of glucose metabolism reprogramming， thus playing a role in the treatment of ulcerative colitis.

ObjectiveTo investigate the effect of Shaoyaotang on T helper cell 17/regulatory T lymphocyte（Th17/Treg） cell balance in ulcerative colitis and decipher the intervention mechanism based on glucose metabolism reprogramming. MethodsThe mouse model of ulcerative colitis was established by the dextran sulfate sodium （DSS） method. Forty-eight C57BL/6 mice were randomly allocated into normal， model， Western drug control （mesalazine， 0.39 g·kg^-1·d^-1）， Shaoyaotang （15.54 g·kg^-1·d^-1）， inhibitor （2-deoxy-D-glucose， 2-DG， 100 mg·kg^-1·d^-1）， and inhibitor （2-DG， 100 mg·kg^-1·d^-1） + Shaoyaotang （15.54 g·kg^-1·d^-1） groups. Mice were administrated with the corresponding drugs by gavage for 7 days. The general conditions and the colon injury degree were observed 24 h after the last administration. The expression of interleukin （IL）-10 and IL-17 in the colon tissue was detected by immunohistochemical staining. Western blot and Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） were performed to determine the protein and mRNA levels， respectively， of hypoxia-inducing factor-1α （HIF-1α）， lactate dehydrogenase （LDHA）， and hexokinase 2 （HK2） in the colon tissue. Th17/Treg cell differentiation was detected by flow cytometry. Enzyme-linked immunosorbent assay was employed to measure the levels of lactic acid and glucose in the colon tissue and IL-10， IL-17， and IL-6 in the serum. ResultsCompared with the normal group， the model group showed decreases in body weight and disease activity index （DAI） （P<0.05）， elevations in levels of HIF-1α， LDHA， HK2， IL-17， IL-6， Th17 cells， lactic acid， and glucose in the colon tissue （P<0.05）， and declines in the levels of of IL-10 and Treg cells （P<0.05）. Compared with the model group， the drug administration groups showed increases in body weight and DAI （P<0.05）， declines in levels of HIF-1α， LDHA， HK2， IL-17， IL-6， Th17 cells， lactic acid， and glucose in the colon tissue （P<0.05）， and rises in levels of IL-10 and Treg cells （P<0.05）. Shaoyaotang+2-DG group had the most obvious effect. ConclusionShaoyaotang can relieve diarrhea and bloody stool in mice with ulcerative colitis by restoring the Th17/Treg cell balance via regulation of glucose metabolism reprogramming， thus playing a role in the treatment of ulcerative colitis.