Hare Dominic J, Kysenius Kai, Paul Bence, Knauer Beate, Hutchinson Robert W, O'Connor Ciaran, Fryer Fred, Hennessey Tom P, Bush Ashley I, Crouch Peter J, Doble Philip A
Elemental Bio-imaging Facility, University of Technology Sydney; Florey Institute of Neuroscience and Mental Health, The University of Melbourne;
Department of Pathology, The University of Melbourne.
J Vis Exp. 2017 Jan 22(119):55042. doi: 10.3791/55042.
Metals are found ubiquitously throughout an organism, with their biological role dictated by both their chemical reactivity and abundance within a specific anatomical region. Within the brain, metals have a highly compartmentalized distribution, depending on the primary function they play within the central nervous system. Imaging the spatial distribution of metals has provided unique insight into the biochemical architecture of the brain, allowing direct correlation between neuroanatomical regions and their known function with regard to metal-dependent processes. In addition, several age-related neurological disorders feature disrupted metal homeostasis, which is often confined to small regions of the brain that are otherwise difficult to analyze. Here, we describe a comprehensive method for quantitatively imaging metals in the mouse brain, using laser ablation - inductively coupled plasma - mass spectrometry (LA-ICP-MS) and specially designed image processing software. Focusing on iron, copper and zinc, which are three of the most abundant and disease-relevant metals within the brain, we describe the essential steps in sample preparation, analysis, quantitative measurements and image processing to produce maps of metal distribution within the low micrometer resolution range. This technique, applicable to any cut tissue section, is capable of demonstrating the highly variable distribution of metals within an organ or system, and can be used to identify changes in metal homeostasis and absolute levels within fine anatomical structures.
金属在生物体中普遍存在，其生物学作用由其化学反应性和在特定解剖区域内的丰度共同决定。在大脑中，金属具有高度分区化的分布，这取决于它们在中枢神经系统中所起的主要作用。对金属的空间分布进行成像，为深入了解大脑的生化结构提供了独特视角，使得神经解剖区域与其在金属依赖过程中的已知功能之间能够建立直接关联。此外，一些与年龄相关的神经系统疾病具有金属稳态失调的特征，这种失调往往局限于大脑中其他难以分析的小区域。在此，我们描述一种使用激光烧蚀 - 电感耦合等离子体质谱法（LA - ICP - MS）和专门设计的图像处理软件对小鼠大脑中的金属进行定量成像的综合方法。聚焦于大脑中含量最丰富且与疾病相关的三种金属——铁、铜和锌，我们描述了样品制备、分析、定量测量和图像处理的关键步骤，以生成低微米分辨率范围内的金属分布图。该技术适用于任何切割的组织切片，能够展示器官或系统内金属的高度可变分布，并可用于识别精细解剖结构内金属稳态和绝对水平的变化。
