Transparent brain with CLARITY histology

Abstract

Microscopy and histological techniques had greatly advanced our understanding of the fine cellular structure of nervous tissue. Nonetheless, the complex tridimensional organization of neurons, glial cells and vasculature is lost in sectioning the brain in order to analyze it under the microscope. Laborious and time consuming methods are employed to reconstruct the 3D organization of cells. Advanced histological techniques like CLARITY, that preserves the cellular protein structure in situ and renders the nervous tissue transparent to light by removing the cellular lipid layers, will allow studies encompassing large volumes of different brain regions. This histology is performed by perfusion of hydrogel monomers that after polymerization creates a protein-monomer hybrid that allows electrophoretic removal of the lipids. The transparent hydrogel can be scanned in a fluorescent microscope after protein immunolabeling.