Optical tissue clearing and immunolabeling in kidney research.

Optical clearing techniques have recently received wide attention for their potential to reveal microcellular structures deep within tissue. Traditional two-dimensional methods are limited for kidney research since renal tubules, glomeruli, vasculature, and other components exist within three dimensions. Equilibrating the refractive index through thick tissue allows subsequent volumetric imaging. Although optical tissue clearing opens up new doors for kidney research, there remain difficulties to find the most suitable methods and to master most multi-step tissue clearing protocols. Here we present a protocol combining immunolabeling and volumetric imaging, which is simple to implement, does not require specialized equipment and provides a tool to study microanatomy in three dimensions.