Bletilla striata polysaccharide improves toxic and side effects induced by 5-FU: an untargeted metabolomics study / 中国中药杂志

This study aimed to analyze the effect of Bletilla striata polysaccharide(BSP) on endogenous metabolites in serum of tumor-bearing mice treated with 5-fluorouracil(5-FU) by untargeted metabolomics techniques and explore the mechanism of BSP in alleviating the toxic and side effects induced by 5-FU. Male BALB/C mice were randomly divided into a normal group, a model group, a 5-FU group, and a 5-FU + BSP group, with eight mice in each group. Mouse colon cancer cells(CT26) were transplanted into the mice except for those in the normal group to construct the tumor-bearing mouse model by subcutaneous injection, and 5-FU chemotherapy and BSP treatment were carried out from the second day of modeling. The changes in body weight, diarrhea, and white blood cell count in the peripheral blood were recorded. The mice were sacrificed and sampled when the tumor weight of mice in the model group reached approximately 1 g. TUNEL staining was used to detect the cell apoptosis in the small intestine of each group. The proportions of hematopoietic stem cells and myeloid progenitor cells in bone marrow were measured by flow cytometry. Five serum samples were selected randomly from each group for untargeted metabolomics analysis. The results showed that BSP was not effective in inhibiting colon cancer in mice, but diarrhea, leukopenia, and weight loss caused by 5-FU chemotherapy were significantly improved after BSP intervention. In addition, apoptotic cells decreased in the small intestinal tissues and the percentages of hematopoietic stem cells and myeloid progenitor cells in bone marrow were significantly higher after BSP treatment. Metabolomics results showed that the toxic and side effects of 5-FU resulted in significant decrease in 29 metabolites and significant increase in 22 metabolites in mouse serum. Among them, 19 disordered metabolites showed a return to normal levels in the 5-FU+BSP group. The results of pathway enrichment indicated that metabolic pathways mainly involved pyrimidine metabolism, arachidonic acid metabolism, and steroid hormone biosynthesis. Therefore, BSP may ameliorate the toxic and side effects of 5-FU in the intestinal tract and bone marrow presumably by regulating nucleotide synthesis, inflammatory damage, and hormone production.

Determination of serum cholesterol by isotope dilution gas chromatography mass spectrometry / 中华检验医学杂志

Objective To develop a new isotope dilution gas chromatography mass spectrometry method (ID/GC/MS) for the measurement of serum cholesterol.Methods Serum was mixed with an isotope labeled internal standard ([3,4-~(13)C]-cholesterol) and treated with alcoholic sodium hydroxide to hydrolyze cholesterol ester to cholesterol.Cholesterol and internal standard was extracted and derived by N, O-Bis(trimethylsilyl) trifluoroacetamide to trimethylsilyl ethers.The derivation products were analyzed by capillary column GC combined with electron impact MS using scan and selected ion monitor (SIM) modes. Signals of cholesterol internal standard were corrected for the contributions from cholesterol and the signal ratio of cholesterol to internal standard for the calibrators were linearly regressed against cholesterol concentrations.The resulted regression equation was used for the calculation of serum cholesterol concentrations.Results The new ID/GC/MS method showed a mean within-run coefficient variance (CV) of 0.04%-0.81%.Comparison with two levels of standard reference material (SRM1951a) of National Institute of Standards and Technology (NIST) displayed a bias of 0.19% and 0.90% respectively.Conclusion A time-gaining ID/MS method has been established that is highly precise and accurate and can be used for the measurement of serum cholesterol.