Rujoi Madalina, Estrada Rosendo, Yappert M Cecilia
Department of Chemistry, University of Louisville, Louisville, Kentucky 40292, USA.
Anal Chem. 2004 Mar 15;76(6):1657-63. doi: 10.1021/ac0349680.
Phospholipids (PLs) are important sources of lipid second messengers that participate in cell signaling pathways. Consequently, their analysis in biological tissues has received increased attention. Current approaches for PL analysis include an extraction step and subsequent identification of the main PL classes by either 31P NMR spectroscopy or chromatographic separation followed by mass spectrometric detection. Previous in vitro studies revealed regional changes in the PL composition of mammalian lenses at different growth stages. In this report, we demonstrate the feasibility of direct in situ analysis of two relevant PL classes, phosphatidylcholines (PCs) and sphingomyelins (SMs), in slices of fresh or fixed (2.5% formaldehyde) mammalian lenses. The chosen matrix was p-nitroaniline, as it generated superior sensitivity when compared to 2,5-dihydroxybenzoic acid, the compound most commonly used for in vitro analysis of PLs by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS). Regional differences in the relative amounts of PCs and SMs were in agreement with trends demonstrated by previous in vitro studies. Fresh and fixed tissue of the same lens gave comparable relative levels of PCs and SMs. In situ analysis of PLs by MALDI-TOF MS offers a rapid and sensitive tool for the mapping of PLs in biological tissues.
磷脂（PLs）是参与细胞信号通路的脂质第二信使的重要来源。因此，它们在生物组织中的分析受到了越来越多的关注。目前的PL分析方法包括提取步骤，随后通过31P核磁共振光谱或色谱分离并结合质谱检测来鉴定主要的PL类别。先前的体外研究揭示了哺乳动物晶状体在不同生长阶段PL组成的区域变化。在本报告中，我们证明了在新鲜或固定（2.5%甲醛）的哺乳动物晶状体切片中直接原位分析两种相关PL类别，即磷脂酰胆碱（PCs）和鞘磷脂（SMs）的可行性。选择的基质是对硝基苯胺，因为与2,5-二羟基苯甲酸相比，它在通过基质辅助激光解吸/电离飞行时间（MALDI-TOF）质谱（MS）进行PL体外分析时产生了更高的灵敏度。PCs和SMs相对含量的区域差异与先前体外研究显示的趋势一致。同一晶状体的新鲜组织和固定组织给出了相当的PCs和SMs相对水平。通过MALDI-TOF MS对PL进行原位分析为生物组织中PL的图谱绘制提供了一种快速且灵敏的工具。
