A cost-effective and efficient ex vivo, ex situ human whole brain perfusion protocol for immunohistochemistry

Background: Chemical fixation of the brain can be executed through either the immersion method or the perfusion method. Perfusion fixation allows for better preservation of the brain tissue's ultrastructure, as it provides rapid and uniform delivery of the fixative to the tissue. Still, not all facilities have the expertise to perform perfusion fixation, with initial high cost and complexity of perfusion systems as the main factors limiting its widespread usage. New method: Here we present our low-cost approach of whole brain ex situ perfusion fixation to overcome the aforementioned limitations. Our self-made perfusion system, constructed utilising commercially accessible and affordable medical resources alongside laboratory and everyday items, demonstrates the capability to generate superior histological stainings of brain tissue. The perfused tissue can be stored prior to proceeding with IHC for at least one year. Results: Our method yielded high-quality results in histological stainings using both free-floating cryosections and paraffin-embedded tissue sections. The system is fully reusable and complies with the principles of sustainable management. Comparison with existing methods: Our whole brain perfusion system has been assembled from simple components and is able to achieve a linear flow with a pressure of 70 mmHg corresponding to the perfusion pressure of the brain. Conclusions: Our ex situ method can be especially useful in research settings where expensive perfusion systems are not affordable or in any field with high time pressure, making it suitable for the field of forensic medicine or pathology in general.