Institute of Inorganic and Analytical Chemistry, University of Münster, Münster, Germany.
Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway.
Metallomics. 2022 Mar 28;14(3). doi: 10.1093/mtomcs/mfac013.
A rapid and cost-efficient tissue preparation protocol for laser ablation-inductively coupled plasma-mass spectrometry imaging (LA-ICP-MSI) has been developed within this study as an alternative to the current gold standard using fresh-frozen samples or other preparation techniques such as formalin fixation (FFix) and formalin-fixed paraffin-embedding (FFPE). Samples were vacuum dried at room temperature (RT) and stored in sealed vacuum containers for storage and shipping between collaborating parties. We compared our new protocol to established methods using prostate tissue sections investigating typical endogenous elements such as zinc, iron, and phosphorous with LA-ICP-MSI. The new protocol yielded comparable imaging results as fresh-frozen sections. FFPE sections were also tested due to the wide use and availability of FFPE tissue. However, the FFPE protocol and the FFix alone led to massive washout of the target elements on the sections tested in this work. Therefore, our new protocol presents an easy and rapid alternative for tissue preservation with comparable results to fresh-frozen sections for LA-ICP-MSI. It overcomes washout risks of commonly used tissue fixation techniques and does not require expensive and potentially unstable and time-critical shipping of frozen material on dry ice. Additionally, this protocol is likely applicable for several bioimaging approaches, as the dry condition may act comparable to other dehydrating fixatives, such as acetone or methanol, preventing degradation while avoiding washout effects.
本研究中开发了一种快速且经济高效的组织制备方案，用于激光烧蚀-电感耦合等离子体质谱成像（LA-ICP-MS），以替代当前使用新鲜冷冻样本或其他制备技术（如福尔马林固定（FFix）和福尔马林固定石蜡包埋（FFPE））的金标准。样本在室温下进行真空干燥，并储存在密封的真空容器中，以便在合作方之间进行储存和运输。我们使用前列腺组织切片比较了我们的新方案与使用 LA-ICP-MS 研究典型内源性元素（如锌、铁和磷）的既定方法。新方案产生了与新鲜冷冻切片相当的成像结果。由于 FFPE 组织的广泛使用和可用性，我们也测试了 FFPE 切片。然而，在这项工作中测试的切片上，FFPE 方案和单独的 FFix 导致目标元素大量洗脱。因此，我们的新方案为组织保存提供了一种简单快速的替代方案，对于 LA-ICP-MS 成像，其结果可与新鲜冷冻切片相媲美。它克服了常用组织固定技术的洗脱风险，并且不需要昂贵且潜在不稳定和时间关键的干冰冷冻材料运输。此外，该方案可能适用于几种生物成像方法，因为干燥条件可能与其他脱水固定剂（如丙酮或甲醇）相当，可防止降解，同时避免洗脱效应。
