title: 3D Imaging of Axons in Transparent Spinal Cords from Rodents and Nonhuman Primates
abstract: The histological assessment of spinal cord tissue in three dimensions has previously been very time consuming and prone to errors of interpretation. Advances in tissue clearing have significantly improved visualization of fluorescently labelled axons. While recent proof-of-concept studies have been performed with transgenic mice in which axons were prelabeled with GFP, investigating axonal regeneration requires stringent axonal tracing methods as well as the use of animal models in which transgenic axonal labeling is not available. Using rodent models of spinal cord injury, we labeled axon tracts of interest using both adeno-associated virus and chemical tracers and performed tetrahydrofuran-based tissue clearing to image multiple axon types in spinal cords using light sheet and confocal microscopy. Using this approach, we investigated the relationships between axons and scar-forming cells at the injury site as well as connections between sensory axons and motor pools in the spinal cord. In addition, we used these methods to trace axons in nonhuman primates. This reproducible and adaptable virus-based approach can be combined with transgenic mice or with chemical-based tract-tracing methods, providing scientists with flexibility in obtaining axonal trajectory information from transparent tissue.
authors.affiliation: Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami School of Medicine, Miami, Florida 33136.
authors.forename: Cynthia
authors.initials: C
authors.lastname: Soderblom
authors.affiliation: Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami School of Medicine, Miami, Florida 33136.
authors.forename: Do-Hun
authors.initials: DH
authors.lastname: Lee
authors.affiliation: Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami School of Medicine, Miami, Florida 33136.
authors.forename: Abdul
authors.initials: A
authors.lastname: Dawood
authors.affiliation: Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami School of Medicine, Miami, Florida 33136.
authors.forename: Melissa
authors.initials: M
authors.lastname: Carballosa
authors.affiliation: Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami School of Medicine, Miami, Florida 33136.
authors.forename: Andrea
authors.initials: A
authors.lastname: Jimena Santamaria
authors.affiliation: Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami School of Medicine, Miami, Florida 33136.
authors.forename: Francisco D
authors.initials: FD
authors.lastname: Benavides
authors.affiliation: Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami School of Medicine, Miami, Florida 33136.
authors.forename: Stanislava
authors.initials: S
authors.lastname: Jergova
authors.affiliation: Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami School of Medicine, Miami, Florida 33136.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Grumbles
authors.affiliation: Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami School of Medicine, Miami, Florida 33136.
authors.forename: Christine K
authors.initials: CK
authors.lastname: Thomas
authors.affiliation: Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami School of Medicine, Miami, Florida 33136.
authors.forename: Kevin K
authors.initials: KK
authors.lastname: Park
authors.affiliation: Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami School of Medicine, Miami, Florida 33136.
authors.forename: James David
authors.initials: JD
authors.lastname: Guest
authors.affiliation: Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami School of Medicine, Miami, Florida 33136.
authors.forename: Vance P
authors.initials: VP
authors.lastname: Lemmon
authors.affiliation: Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami School of Medicine, Miami, Florida 33136.
authors.forename: Jae K
authors.initials: JK
authors.lastname: Lee
authors.affiliation: Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami School of Medicine, Miami, Florida 33136.
authors.forename: Pantelis
authors.initials: P
authors.lastname: Tsoulfas
keywords: 3DISCO; axon regeneration; spinal cord injury; tissue clearing