title: A rat model of chronic syringomyelia induced by epidural compression of the lumbar spinal cord.
abstract: OBJECTIVE There has been no established animal model of syringomyelia associated with lumbosacral spinal lipoma. The research on the pathophysiology of syringomyelia has been focused on Chiari malformation, trauma, and inflammation. To understand the pathophysiology of syringomyelia associated with occult spinal dysraphism, a novel animal model of syringomyelia induced by chronic mechanical compression of the lumbar spinal cord was created. METHODS The model was made by epidural injection of highly concentrated paste-like kaolin solution through windows created by partial laminectomy of L-1 and L-5 vertebrae. Behavioral outcome in terms of motor (Basso-Beattie-Bresnahan score) and urinary function was assessed serially for 12 weeks. Magnetic resonance images were obtained in some animals to confirm the formation of a syrinx and to monitor changes in its size. Immunohistochemical studies, including analysis for glial fibrillary acidic protein, NeuN, CC1, ED-1, and caspase-3, were done. RESULTS By 12 weeks after the epidural compression procedure, syringomyelia formation was confirmed in 85% of the rats (34 of 40) on histology and/or MRI. The syrinx cavities were found rostral to the epidural compression. Motor deficit of varying degrees was seen immediately after the procedure in 28% of the rats (11 of 40). In 13 rats (33%), lower urinary tract dysfunction was seen. Motor deficit improved by 5 weeks after the procedure, whereas urinary dysfunction mostly improved by 2 weeks. Five rats (13%, 5 of 40) died 1 month postoperatively or later, and 3 of the 5 had developed urinary tract infection. At 12 weeks after the operation, IHC showed no inflammatory process, demyelination, or accelerated apoptosis in the spinal cords surrounding the syrinx cavities, similar to sham-operated animals. CONCLUSIONS A novel experimental model for syringomyelia by epidural compression of the lumbar spinal cord has been created. The authors hope that it will serve as an important research tool to elucidate the pathogenesis of this type of syringomyelia, as well as the CSF hydrodynamics of the lumbar spinal cord.
authors.affiliation: Departments of 1 Anatomy and.|Neural Development and Anomaly Laboratory, Seoul National University College of Medicine.|Division of Pediatric Neurosurgery.
authors.forename: Ji Yeoun
authors.initials: JY
authors.lastname: Lee
authors.affiliation: Neural Development and Anomaly Laboratory, Seoul National University College of Medicine.
authors.forename: Shin Won
authors.initials: SW
authors.lastname: Kim
authors.affiliation: Departments of 1 Anatomy and.|Neural Development and Anomaly Laboratory, Seoul National University College of Medicine.
authors.forename: Saet Pyoul
authors.initials: SP
authors.lastname: Kim
authors.affiliation: Department of Radiology.
authors.forename: Hyeonjin
authors.initials: H
authors.lastname: Kim
authors.affiliation: Department of Radiology.
authors.forename: Jung-Eun
authors.initials: JE
authors.lastname: Cheon
authors.affiliation: Division of Pediatric Neurosurgery.|Department of Neurosurgery, Seoul National University Children's Hospital and Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Seung-Ki
authors.initials: SK
authors.lastname: Kim
authors.affiliation: Department of Neurosurgery, Seoul National University Children's Hospital and Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Sun Ha
authors.initials: SH
authors.lastname: Paek
authors.affiliation: Department of Pediatric Neurosurgery, University of California, Davis; and.|Regional Center of Pediatric Neurosurgery, Oakland Medical Center, Kaiser Foundation Hospitals of Northern California, Oakland, California.
authors.forename: Dachling
authors.initials: D
authors.lastname: Pang
authors.affiliation: Neural Development and Anomaly Laboratory, Seoul National University College of Medicine.|Division of Pediatric Neurosurgery.|Department of Neurosurgery, Seoul National University Children's Hospital and Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Kyu-Chang
authors.initials: KC
authors.lastname: Wang
mesh_terms: D000818:Animals; D002908:Chronic Disease; D004195:Disease Models, Animal; D004824:Epidural Space; D007150:Immunohistochemistry; D007616:Kaolin; D007796:Laminectomy; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D009043:Motor Activity; D009069:Movement Disorders / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D013595:Syringomyelia / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D014554:Urination
chemical_list: D007616:Kaolin
keywords: BBB = Basso-Beattie-Bresnahan; GFAP = glial fibrillary acidic protein; H & E = hematoxylin and eosin; IHC = immunohistochemical; IP = intraperitoneal; LFB = Luxol fast blue; PBS = phosphate-buffered saline; SCI = spinal cord injury; epidural compression; lumbar spinal cord; occult spinal dysraphism; syringomyelia