Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Zurich, Zurich, Switzerland; University of Zurich, Zurich, Switzerland.
Otopathology Laboratory, Department of Otolaryngology, Massachusetts Eye and Ear, Boston, Massachusetts.
J Histochem Cytochem. 2024 Jul;72(7):419-433. doi: 10.1369/00221554241266287. Epub 2024 Jul 25.
Pathology repositories worldwide store millions of celloidin-processed human brain and temporal bone (TB) sections vital for studying central nervous system diseases and sensory organs. However, accessing these sections for modern molecular-pathological research, like immunohistochemistry, is hindered by the challenge of removing celloidin without damaging tissue. In this study, we explored the use of polyethylene glycols (PEGs), a class of non-hazardous, ethylene glycol oligomers, combined with an improved section mounting technique, to gently and effectively dissolve celloidin from sections archived for up to 40 years. Optimizing our protocol involved exploring celloidin dissolution kinetics in PEGs of varying molecular weights and terminations, as well as different temperatures. Low molecular weight PEGs, particularly PEG 200, were the most efficient celloidin solvent. Nuclear magnetic resonance (NMR) spectroscopy of celloidin-PEG 200 dissolution products revealed no chemical alterations, suggesting pure solvation without chemical modification. Because the solvation of celloidin in PEG was inhibited by proteins, we further developed a protein-free mounting protocol allowing complete celloidin removal in 30 to 60 minutes by immersing in PEG 200. In summary, our approach overcomes major methodological hurdles, rendering decades-old archival celloidin sections viable for immunohistochemical and other molecular biological techniques, while enhancing safety and workflow efficiency.
全世界的病理学知识库都储存着数以百万计的经过明胶包埋处理的人脑和颞骨（TB）切片，这些切片对于研究中枢神经系统疾病和感觉器官至关重要。然而，要将这些切片用于现代的分子病理学研究，如免疫组织化学，就会面临去除明胶而不损坏组织的挑战。在这项研究中，我们探索了使用聚乙二醇（PEGs）——一种非危险的乙二醇低聚物，结合改进的切片安装技术，温和有效地溶解归档长达 40 年的明胶切片。优化我们的方案涉及探索不同分子量和端基的 PEG 中明胶溶解动力学，以及不同温度下的情况。低分子量 PEG，特别是 PEG 200，是最有效的明胶溶剂。明胶-PEG 200 溶解产物的核磁共振（NMR）光谱显示没有化学变化，表明是纯粹的溶剂化而没有化学修饰。由于 PEG 中的明胶的溶剂化受到蛋白质的抑制，我们进一步开发了一种无蛋白的安装方案，通过将切片浸泡在 PEG 200 中，可以在 30 到 60 分钟内完全去除明胶。总之，我们的方法克服了主要的方法学障碍，使数十年前的存档明胶切片能够用于免疫组织化学和其他分子生物学技术，同时提高了安全性和工作流程效率。
