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Authors & Affiliations
Eve-Marie Frigon, Amy Gérin-Lajoie, Mahsa Dadar, Denis Boire, Josefina Maranzano
Abstract
Brain banks provide small tissue samples to researchers, while gross-anatomy laboratories could provide complete brains, but these are preserved with solutions appropriate for gross-dissection, different from the classic neutral-buffered-formalin (NBF) used in brain banks. Our previous work in mice showed that two gross-anatomy laboratory solutions, a saturated-salt-solution (SSS) and an alcohol-formaldehyde-solution (AFS), preserve antigenicity of the main cellular markers. Our goal is now to compare the histology and antigenicity preservation of human brains fixed following: 1-brain bank practices (immersion in NBF); 2-gross-anatomy practices (perfusion with SSS or AFS).We used 42 brains (3:1 male-female; 25-90 years old) fixed with NBF, SSS or AFS (N=12;13;17). We sliced 1 cm3 blocks into 40mm sections and processed with immunohistochemistry to label four cell types (e.g. neurons using NeuN, astrocytes using GFAP, microglia using Iba1, and myelin using PLP, etc.). We also assessed histochemical stains (e.g., Cresyl-violet, Luxol-fast-blue, etc.) across solutions.The four antigens were preserved, and cell labeling was more often homogeneous in AFS-fixed specimens. NeuN and GFAP were not always present in the NBF and SSS samples. Some antigens were heterogeneously distributed in some specimens, despite the fixative, but an antigen retrieval protocol recovered them. Finally, the histochemical stains were of sufficient quality in most specimens, although neurons were more often paler in SSS-fixed specimens.Antigenicity and histochemical stains’ quality were preserved in human brains fixed with gross-anatomy solutions. For some specific variables, histology quality was superior in AFS-fixed brains. These results are promising for neuroscientists interested in using anatomy labs’ brains.