title: Leg dysfunctions in a hatched chick model of spina bifida aperta.
abstract: We created chicks with spina bifida aperta (SBA) by incising the roof plate of the neural tube of embryos at Hamburger and Hamilton stage 18 or 19. Incision over the length of three somites caused spina bifida occulta (SBO)-like malformation in 47% of the hatchlings. Incision over the length of five and seven somites caused SBA-like malformation in 100% of the hatchlings. The SBO chicks exhibited no symptoms, whereas the SBA chicks exhibited paralysis of a leg muscle and imbalance between an agonist and an antagonist leg muscles. Lesions in these SBA chicks were located in the spinal segments that give rise to motor neurons that innervated the dysfunctional muscles. Histological analysis revealed that there were fewer small spinal neurons (interneurons) at the site of the lesion in SBA chicks than in the normal chicks and that there was no such difference in the number of the large spinal neurons (motor neurons). Leg dysfunctions in this model of SBA may be attributable to the smaller number of interneurons in the spinal segments that contain motor neurons that innervate the dysfunctional muscle. This model may facilitate studies of the pathological mechanisms that lead to leg dysfunctions in SBA chicks.
authors.affiliation: Department of Biological Resources, Integrated Center for Science, Ehime University, Shitsukawa, Toon City, Ehime 791-0295, Japan. momi@m.ehime-u.ac.jp
authors.forename: Katsumi
authors.initials: K
authors.lastname: Mominoki
authors.forename: Masae
authors.initials: M
authors.lastname: Kinutani
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Wakisaka
authors.forename: Shouichirou
authors.initials: S
authors.lastname: Saito
authors.forename: Naoto
authors.initials: N
authors.lastname: Kobayashi
authors.forename: Takashi
authors.initials: T
authors.lastname: Fujiwara
authors.forename: Seiji
authors.initials: S
authors.lastname: Matsuda
mesh_terms: D000818:Animals; D002452:Cell Count; D002642:Chick Embryo; D002645:Chickens / Q000502:physiology*; D004805:Ependyma / Q000166:cytology; D007395:Interneurons / Q000502:physiology; D017880:Limb Deformities, Congenital / Q000503:physiopathology*; D008124:Locomotion / Q000502:physiology; D008866:Microsurgery; D009046:Motor Neurons / Q000502:physiology; D018482:Muscle, Skeletal / Q000294:innervation / Q000503:physiopathology; D009436:Neural Tube Defects / Q000453:epidemiology / Q000503:physiopathology; D010243:Paralysis / Q000503:physiopathology; D004856:Postural Balance / Q000502:physiology; D013116:Spinal Cord / Q000002:abnormalities / Q000473:pathology; D016135:Spinal Dysraphism / Q000473:pathology*; D013534:Survival