Walsh Kevin J, Shah Stavan V, Wei Ping, Oberdick Samuel D, Karn Nicole M, McTigue Dana M, Agarwal Gunjan
Biophysics Program (The Ohio State University).
Department of Biomedical Engineering (The Ohio State University).
J Magn Magn Mater. 2021 Mar;521(Pt 1). doi: 10.1016/j.jmmm.2020.167531. Epub 2020 Nov 10.
Characterizing the iron distribution in tissue sections is important for several pathologies. Iron content in excised tissue is typically analyzed via histochemical stains, which are dependent on sample preparation and staining protocols. In our recent studies, we examined how magnetic properties of iron can also be exploited to characterize iron distribution in tissue sections in a label free manner. To enable a histomagnetic characterization of iron in a wide variety of available tissues, it is important to extend it to samples routinely prepared for histochemical staining, which often involve use of chemical fixatives. In this study, we took a systematic approach to determine differences between unfixed and formalin-fixed murine spleen tissues in histomagnetic characterization of iron. Superconducting quantum interference device (SQUID) magnetometry and magnetic force microscopy (MFM) were used for macro- and micro-scale histomagnetic characterization. Perl's stain was used for histochemical characterization of ferric (Fe) iron on adjacent sections as that used for MFM analysis. While histochemical analysis revealed a substantial difference in the dispersion of the stain between fixed versus unfixed samples, histomagnetic characterization was not dependent on chemical fixation of tissue. The results from this study reveal that histomagnetic characterization of iron is free from staining artifacts which can be present in histochemical analysis.
表征组织切片中的铁分布对于多种病理学研究都很重要。切除组织中的铁含量通常通过组织化学染色进行分析，而这依赖于样品制备和染色方案。在我们最近的研究中，我们研究了如何利用铁的磁性以无标记方式表征组织切片中的铁分布。为了能够对各种可用组织中的铁进行组织磁学表征，将其扩展到常规用于组织化学染色的样品很重要，这些样品通常涉及使用化学固定剂。在本研究中，我们采用系统方法来确定未固定和福尔马林固定的小鼠脾脏组织在铁的组织磁学表征方面的差异。超导量子干涉装置（SQUID）磁力测量法和磁力显微镜（MFM）用于宏观和微观尺度的组织磁学表征。Perl氏染色用于对与MFM分析所用相邻切片上的三价铁（Fe）进行组织化学表征。虽然组织化学分析显示固定样品与未固定样品之间染色分散度存在显著差异，但组织磁学表征并不依赖于组织的化学固定。本研究结果表明，铁的组织磁学表征不存在组织化学分析中可能出现的染色假象。
