Lundström Yasmin, Lundström Patrik, Popova Svetlana N, Lindblom Rickard P F, Alafuzoff Irina
Department of Immunology, Genetics and Pathology.
Departments of Pathology.
Appl Immunohistochem Mol Morphol. 2019 Mar;27(3):238-245. doi: 10.1097/PAI.0000000000000658.
In this study, we have systematically assessed the influence of postmortem delay (PMD) and fixation time (FT) on the immunohistochemical (IHC) staining outcome. The IHC method is frequently applied on surgical and postmortem samples in diagnostics and research. To replicate the routine situation, brain tissues from pigs were exposed to either storage in a refrigerator (+8°C), that is, PMD (1 to 168 h), or fixed in 10% buffered formalin, that is, FT (18 to 94 d). Subsequently, the tissue was routinely processed into paraffin blocks to enable construction of tissue microarrays (TMA). Sections cut from the TMA blocks were stained applying 13 different antibodies directed against neuronal and glial antigens. Immunoreactivity applying 5 antibodies was influenced by prolonged PMD and applying 2 antibodies by prolonged FT. None of the staining outcomes related to the PMD or FT were predictable. Loss of TMA cores during processing was primarily influenced by pretreatment and by tissue characteristics (gray/white matter). The test model described here confirmed that these 2 variables, PMD and FT, indeed influence the IHC outcome. The PMD and FT are particularly of importance while assessing tissue samples obtained at autopsy. The result above is also of importance while comparing the IHC outcomes seen in the postmortem setting (various PMD/FT) with surgical samples or with IHC outcome seen in experimental animal setting (controlled PMD/FT). Thus, we suggest that the test model described here is considered when assessing the reliability of the IHC outcome when analyzing tissues with various characteristics.
在本研究中，我们系统评估了死后延迟（PMD）和固定时间（FT）对免疫组织化学（IHC）染色结果的影响。免疫组织化学方法在诊断和研究中常用于手术和尸检样本。为模拟常规情况，将猪的脑组织置于冰箱（+8°C）中储存，即造成死后延迟（1至168小时），或用10%中性福尔马林固定，即固定时间（18至94天）。随后，将组织常规处理成石蜡块以构建组织微阵列（TMA）。从TMA块上切下的切片用13种针对神经元和神经胶质抗原的不同抗体进行染色。5种抗体的免疫反应性受延长的死后延迟影响，2种抗体的免疫反应性受延长的固定时间影响。与死后延迟或固定时间相关的染色结果均无法预测。处理过程中TMA芯的丢失主要受预处理和组织特征（灰质/白质）影响。此处描述的测试模型证实，死后延迟和固定时间这两个变量确实会影响免疫组织化学结果。在评估尸检获得的组织样本时，死后延迟和固定时间尤为重要。在将尸检环境（各种死后延迟/固定时间）中观察到的免疫组织化学结果与手术样本或实验动物环境（可控的死后延迟/固定时间）中观察到的免疫组织化学结果进行比较时，上述结果也很重要。因此，我们建议在分析具有不同特征的组织时评估免疫组织化学结果的可靠性时考虑此处描述的测试模型。
