Neurovue as a tracer for human nervous tissue

Abstract

Neurovue is a lipophilic neuronal tract tracer designed for fixed tissues. Although it has been used in perfused animal brains, its use in either human or immersion fixed tissues has not been well documented. Diffusion properties of Neurovue in immersion fixed human optic nerves was studied. Brains were collected from cadavers in the Anatomy Department of SUNY Downstate Medical Center. Brains were immersion fixed in 10% formalin for three days. A Neurovue filter strip was then placed on the right optic nerve. Brains were then re‐immersed in fixative with the filter strip still affixed to allow the tracer to diffuse into the tissue. Neurovue diffusion was grossly evident after only two weeks of exposure to the tracer. After four weeks of exposure, samples were sliced into 5 um sections and examined under fluorescent microscopy at 4× and 10× magnification. Results indicate that Neurovue was successfully transported across the specimen, and there was visible contrast with unlabeled tissue. The tracer traveled a path from the right optic nerve to the contralateral side of the optic chiasm, following the expected course of optic nerve tracts. This study shows that Neurovue can be used as a marker in human fixed tissue without utilizing perfusion procedures. Future studies will evaluate Neurovue in labeling human cortical connections, and the feasibility of its use in macroscopic visualizations.