title: Spinal Cord Ependymal Responses to Naturally Occurring Traumatic Spinal Cord Injury in Dogs.
abstract: The spinal cord ependymal layer (SEL) is a recent focus in spinal cord injury (SCI) research because of its potential to serve as a source of endogenous neural stem cells. Dogs are an important spontaneous model of SCI; however, there is a paucity of information available in the literature regarding the canine SEL. Here we describe the histologic appearance and immunohistochemical staining patterns of the SEL in normal dogs (n = 4) and dogs with acute SCI caused by intervertebral disk extrusion (n = 7). Immunohistochemical staining for PCNA, Ki-67, caspase 3, E-cadherin, GFAP, and vimentin was employed in both groups. Staining for Ki-67 was absent in the SEL of normal and SCI-affected dogs, indicating possible restricted proliferative capacity of the canine SEL acutely after SCI. GFAP-positive cells were increased after SCI at both at the lesion epicenter and at proximal spinal cord sites (P = .001 and P = .006, respectively), supporting the possibility of astrocytic differentiation within the SEL after SCI. Total E-cadherin staining did not differ between normal and SCI-affected dogs (P = .42 for lesion epicenter, P = .09 at proximal sites) and was restricted to the apical cell surface in normal dogs. After SCI, E-cadherin staining was membrane-circumferential and cytosolic in nature, indicating possible loss of cellular polarity after injury that could drive cell migration from the SEL to injury sites. Enhanced GFAP expression and changes in E-cadherin expression patterns support additional studies to evaluate the canine SEL as a source of endogenous neural precursors that may be modulated for future clinical interventions after SCI.
authors.affiliation: Department of Veterinary Clinical Sciences (SAM), The Ohio State University, College of Veterinary Medicine, Columbus, OH, USA moore.2204@osu.edu.
authors.forename: S A
authors.initials: SA
authors.lastname: Moore
authors.affiliation: Department of Veterinary Biosciences (MJO), The Ohio State University, College of Veterinary Medicine, Columbus, OH, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Oglesbee
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000032:analysis; D002454:Cell Differentiation; D002465:Cell Movement; D049109:Cell Proliferation; D004283:Dog Diseases / Q000378:metabolism* / Q000473:pathology; D004285:Dogs; D004805:Ependyma / Q000378:metabolism / Q000473:pathology; D007150:Immunohistochemistry / Q000662:veterinary; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis; D013116:Spinal Cord / Q000378:metabolism / Q000473:pathology; D013119:Spinal Cord Injuries / Q000378:metabolism / Q000473:pathology / Q000662:veterinary*
chemical_list: D015415:Biomarkers; D018809:Proliferating Cell Nuclear Antigen
keywords: cell-based therapy; dog; ependyma; immunohistochemistry; neural stem cells; spinal cord injury