Seeley Erin H, Oppenheimer Stacey R, Mi Deming, Chaurand Pierre, Caprioli Richard M
Mass Spectrometry Research Center and Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
J Am Soc Mass Spectrom. 2008 Aug;19(8):1069-77. doi: 10.1016/j.jasms.2008.03.016. Epub 2008 Apr 8.
MALDI imaging mass spectrometry (IMS) has become a valuable tool for the investigation of the content and distribution of molecular species in tissue specimens. Numerous methodological improvements have been made to optimize tissue section preparation and matrix deposition protocols, as well as MS data acquisition and processing. In particular for proteomic analyses, washing the tissue sections before matrix deposition has proven useful to improve spectral qualities by increasing ion yields and the number of signals observed. We systematically explore here the effects of several solvent combinations for washing tissue sections. To minimize experimental variability, all of the measurements were performed on serial sections cut from a single mouse liver tissue block. Several other key steps of the process such as matrix deposition and MS data acquisition and processing have also been automated or standardized. To assess efficacy, after each washing procedure the total ion current and number of peaks were counted from the resulting protein profiles. These results were correlated to on-tissue measurements obtained for lipids. Using similar approaches, several selected washing procedures were also tested for their ability to extend the lifetime as well as revive previously cut tissue sections. The effects of these washes on automated matrix deposition and crystallization behavior as well as their ability to preserve tissue histology were also studied. Finally, in a full-scale IMS study, these washing procedures were tested on a human renal cell carcinoma biopsy.
基质辅助激光解吸电离成像质谱（MALDI-IMS）已成为研究组织标本中分子种类的含量和分布的重要工具。人们在优化组织切片制备、基质沉积方案以及质谱数据采集和处理方面取得了许多方法上的改进。特别是在蛋白质组学分析中，已证明在基质沉积前洗涤组织切片有助于通过提高离子产率和增加观察到的信号数量来改善光谱质量。我们在此系统地探索了几种溶剂组合对组织切片洗涤的效果。为了尽量减少实验变异性，所有测量均在从单个小鼠肝脏组织块切下的连续切片上进行。该过程的其他几个关键步骤，如基质沉积、质谱数据采集和处理，也已实现自动化或标准化。为了评估效果，在每次洗涤程序后，从所得蛋白质谱中计算总离子电流和峰数。这些结果与在组织上获得的脂质测量结果相关。使用类似方法，还测试了几种选定的洗涤程序延长寿命以及恢复先前切割的组织切片的能力。还研究了这些洗涤对自动基质沉积和结晶行为的影响以及它们保持组织组织学的能力。最后，在一项全面的成像质谱研究中，这些洗涤程序在人类肾细胞癌活检样本上进行了测试。
