title: Vertebral growth disturbance in rapidly growing rats during 14 days of spaceflight.
abstract: The effect of 14 days of spaceflight on the vertebrae of rapidly growing rats was studied. The hardness of the vertebrae was measured with a Knoop microhardness tester, and bone mineral density was measured from X-ray photographs. Histomorphometric examination was performed with a microcomputer-aided system. No significant difference (P > 0.05) was observed between flight rats and ground controls with regard to mechanical hardness or bone mineral density. However, histological examination revealed irregular thickening of the endosteal surface of cortical bone in the flight rats, whereas it was uniform in the ground controls. The relative area of lamellar bone showed a significant reduction (P < 0.001) in the flight rats. These findings suggest that the structural disturbances were due to retardation of endosteal modeling and remodeling. We conclude that delay of vertebral maturation can occur in rapidly growing rats after even short-term exposure to microgravity.
authors.affiliation: Department of Laboratory Medicine, Kagoshima University, Japan.
authors.forename: I
authors.initials: I
authors.lastname: Kitajima
authors.forename: I
authors.initials: I
authors.lastname: Semba
authors.forename: T
authors.initials: T
authors.lastname: Noikura
authors.forename: K
authors.initials: K
authors.lastname: Kawano
authors.forename: Y
authors.initials: Y
authors.lastname: Iwashita
authors.forename: I
authors.initials: I
authors.lastname: Takasaki
authors.forename: I
authors.initials: I
authors.lastname: Maruyama
authors.forename: H
authors.initials: H
authors.lastname: Arikawa
authors.forename: K
authors.initials: K
authors.lastname: Inoue
authors.forename: N
authors.initials: N
authors.lastname: Shinohara
authors.forename: S
authors.initials: S
authors.lastname: Nagaoka
authors.forename: Y
authors.initials: Y
authors.lastname: Ohira
mesh_terms: D000818:Animals; D001510:Bed Rest / Q000009:adverse effects; D001696:Biomechanical Phenomena; D015519:Bone Density / Q000502:physiology; D006244:Hardness; D007091:Image Processing, Computer-Assisted; D008297:Male; D011859:Radiography; D051381:Rats; D017207:Rats, Sprague-Dawley; D013026:Space Flight; D013904:Thoracic Vertebrae / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000254:growth & development*