气相色谱-质谱联用法分析肠炎小鼠短链脂肪酸代谢

目的 建立气相色谱-质谱联用（GC/MS）的短链脂肪酸（SCFAs）分析方法，分析肠炎小鼠SCFAs代谢情况。方法 盐酸饱和氯化钠溶液酸化生物样本，醋酸乙酯提取SCFAs后衍生化，建立GC/MS方法进行生物样本中SCFAs测定；考察盐酸溶液提取和盐酸饱和氯化钠溶液提取SCFAs总离子流图谱；考察SCFAs混合物衍生化前后的稳定性，粪便、血清、小肠、结肠、肝脏组织中SCFAs测定方法的线性、精密度及准确度、提取回收率和基质效应。运用建立的方法对正常及硫酸葡聚糖（DSS）慢性肠炎小鼠血、肝、小肠、结肠、结肠内容物以及盲肠内容物中发挥重要作用的SCFAs进行测定。结果 用盐酸饱和氯化钠溶液进行SCFAs提取后，建立的GC/MS法可同时测定甲酸、乙酸、丙酸、异丁酸、丁酸、异戊酸、戊酸、异己酸、己酸、乳酸、琥珀酸共11种SCFAs；方法学考证显示，该方法具有较好的准确度、精密度以及提取回收率；除乙酸外，其余SCFAs基质效应均较好，不能完全除去乙酸的基质效应，但其RSD均小于3.8%，说明基质的影响效应相对稳定，对结果准确性影响较小。与对照组比较，慢性肠炎小鼠结肠内容物SCFAs蓄积；盲肠内容物SCFAs整体下调，乳酸蓄积，提示肠炎小鼠SCFAs代谢紊乱。结论 建立了生物样品中SCFAs提取和检测方法，并应用于慢性肠炎小鼠SCFAs代谢分析，肠炎小鼠SCFAs代谢紊乱。

Analysis on SCFAs dysregulation pattern in experimental colitis mice based on gas chromatography-mass spectrometer

Objective To analyze the metabolism of short chain fatty acids (SCFAs) in enteritis mice by gas chromatography-mass spectrometry (GC/MS). Method The pretreatment of biological samples contains acidification in sodium chloride solution saturated with hydrochloric acid, ethyl acetate extraction, and derivatization. GC/MS method is established to quantify SCFAs in biological samples. Total ion chromatograms of SCFAs of fecal samples extracted by hydrochloric acid solution and hydrochloric acid saturated sodium chloride solution were observed. The stability of the SCFAs mixture before and after the derivatization, the linearity, precision, accuracy, recovery, and the matrix effect of SCFAs determination in feces, sera, small intestine, colon, and liver tissues were investigated. The established method was used to determine the important SCFAs in the blood, liver, small intestine, colon, colon content, and the content of cecum in normal and DSS chronic enteritis mice. Results The method could quantify 11 different kinds of SCFAs including formic acid, acetic acid, propionic acid, isobutyric acid, butyric acid, isovalerate, valerate, ISO caproic acid, hexanoic acid, lactic acid, and succinic acid in biological samples extracted by hydrochloric acid saturated sodium chloride solution with great accuracy, precision, and extraction recovery. Except for acetic acid, the other SCFAs matrix effects were all good, and the matrix effect of acetic acid could not be completely removed, but the RSD was less than 3.8%, indicating that the effect of matrix was relatively stable and had little effect on the accuracy of the results. The method has been used to analyze SCFAs in mouse intestinal contents, liver, small intestinal, and colon. Compared with control group, colitis mouse showed SCFAs metabolic disorder caused by SCFAs accumulation in colon content and SCFAs reduction except for lactic acid in cecum content. Conclusion The SCFAs extraction and quantification method has been established and applied to analyze SCFAs in colitis mouse, and colitis mouse showed SCFAs metabolic disorder.