Department of Optometry and Vision Science, The University of Alabama at Birmingham, Birmingham, AL, USA.
Methods Mol Biol. 2021;2306:157-170. doi: 10.1007/978-1-0716-1410-5_11.
The precorneal tear film keeps the eye surface moist and helps to maintain normal eye function. The outermost lipid layer of the tear film, which attenuates tear film evaporation, contains meibum secreted from the meibomian gland. Most meibum lipids are neutral, including wax esters (WEs), cholesteryl esters (CEs), and diesters (DEs), along with some polar lipids including free fatty acids (FFAs), O-acyl-ω-hydroxy fatty acids (OAHFAs), and trace phospholipids. Detection of neutral lipids by mass spectrometry (MS) is challenging due to interference from impurities, particularly when working with minute-volume meibum samples. Here, we describe procedures for sample preparation and MS analysis of these elusive meibum lipids that can be used to examine dry eye disease mechanisms. Because the method described here minimizes impurity peaks for lipids generally, neutral and otherwise, it may be applied to high-sensitivity analysis of other biological samples.
角膜前泪膜保持眼睛表面湿润，有助于维持正常的眼睛功能。泪膜的最外层脂质层可以减少泪膜蒸发，其中包含由睑板腺分泌的睑脂。大多数睑脂脂质为中性，包括蜡酯 (WE)、胆固醇酯 (CE) 和二酯 (DE)，以及一些极性脂质，包括游离脂肪酸 (FFA)、O-酰基-ω-羟基脂肪酸 (OAHFA) 和痕量磷脂。由于杂质的干扰，尤其是在处理微量的睑脂样本时，通过质谱 (MS) 检测中性脂质具有挑战性。在这里，我们描述了用于这些难以捉摸的睑脂的样品制备和 MS 分析的程序，可用于研究干眼症发病机制。由于此处描述的方法可最大程度地减少一般脂质（包括中性脂质）的杂质峰，因此它可能适用于其他生物样品的高灵敏度分析。
