Sonoda Ai, Nihei Masayuki, Shinkawa Norihiro, Kakizaki Eiji, Yukawa Nobuhiro
Division of Legal Medicine, Department of Social Medicine, Faculty of Medicine, University of Miyazaki, Japan.
Department of Chemistry, Institute of Pure and Applied Sciences, University of Tsukuba, Japan.
Forensic Sci Int Synerg. 2025 Jul 10;11:100627. doi: 10.1016/j.fsisyn.2025.100627. eCollection 2025 Dec.
Perls' Prussian blue staining or reaction is used to detect haemosiderin, which is stored or sequestrated non-haeme iron. Methodologically, the iron in haemosiderin is released as Fe (Fe) by hydrochloric acid (HCl), and Fe reacts with potassium ferrocyanide (K[Fe(CN)]) to form Prussian blue. Iron released from ferritin, another stored non-haeme iron, is too scarce to be detected. Haeme iron, including haemoglobin and cytochromes, is not released by HCl. Thus, haemosiderin can easily be detected under the microscope as distinct blue deposits with minimal background staining. The chemistry of cyanide-bridged iron complexes, including Prussian blue and Turnbull blue, is the basis for understanding Perls' staining. Prussian blue is a cubic lattice with Fe or Fe ions alternately aligned at the corners to give Fe-CN-Fe formations at the edges. Physicochemically, Prussian blue is soluble in water (dispersible as a colloid) or insoluble depending on how it is formed. As with Perls' staining, Prussian blue is expected to take a soluble form because of excess K[Fe(CN)] compared to Fe released from tissues. Notably, Prussian blue used in Perls' staining does not in fact dissipate into the staining solution but remains on the tissue, rendering this a practical method for histological detection of haemosiderin and also exogenous iron of forensic significance. However, further examinations of its mechanisms are needed to evaluate the applicability of this method on various forensics cases.
珀尔斯普鲁士蓝染色或反应用于检测含铁血黄素，含铁血黄素是储存或隔离的非血红素铁。从方法学上讲，含铁血黄素中的铁被盐酸（HCl）释放为Fe（亚铁离子），亚铁离子与亚铁氰化钾（K₄[Fe(CN)₆]）反应形成普鲁士蓝。从另一种储存的非血红素铁铁蛋白中释放的铁太少而无法检测到。包括血红蛋白和细胞色素在内的血红素铁不会被盐酸释放。因此，在显微镜下很容易将含铁血黄素检测为明显的蓝色沉积物，背景染色最少。包括普鲁士蓝和滕氏蓝在内的氰桥铁配合物的化学性质是理解珀尔斯染色的基础。普鲁士蓝是一种立方晶格，Fe³⁺或Fe²⁺离子在角上交替排列，在边缘形成Fe-CN-Fe结构。从物理化学角度看，普鲁士蓝根据其形成方式可溶于水（以胶体形式分散）或不溶。与珀尔斯染色一样，由于与从组织中释放的Fe相比K₄[Fe(CN)₆]过量，普鲁士蓝预计呈可溶形式。值得注意的是，珀尔斯染色中使用的普鲁士蓝实际上不会扩散到染色溶液中，而是保留在组织上，这使得它成为组织学检测含铁血黄素以及具有法医学意义的外源铁的实用方法。然而，需要进一步研究其机制，以评估该方法在各种法医案件中的适用性。
