Visualization of the carotid body in situ in fixed human carotid bifurcations using a xylene-based tissue clearing method

The anatomy of the carotid body (CB) and its nerve supply are important, because it is a potential therapeutic target for treatment of various clinical conditions. Visualization of the CB in situ in fixed human anatomical specimens is hampered by obscuring adipose and connective tissues. We developed a tissue clearing method to optimize identification of the CB. We used single sided carotid bifurcations of six human cadavers fixed long term. Visualization of the CB was accomplished by clearing tissue with xylene. Under incident light, carotid bifurcations exhibited a less transparent, darker colored CB; hematoxylin and eosin stained paraffin sections confirmed its identity. Our visualization of the CB in situ in human carotid bifurcations fixed long term enabled targeted resection and subsequent topographic and morphometric measurements of the CB. Our procedure does not interfere with immunohistochemical staining of sections prepared from such specimens.