title: Adaptations of young adult rat cortical bone to 14 days of spaceflight.
abstract: To determine whether mature humeral cortical bone would be modified significantly by an acute exposure to weightlessness, adult rats (110 days old) were subjected to 14 days of microgravity on the COSMOS 2044 biosatellite. There were no significant changes in peak force, stiffness, energy to failure, and displacement at failure in the flight rats compared with ground-based controls. Concentrations and contents of hydroxyproline, calcium, and mature stable hydroxylysylpyridinoline and lysylpyridinoline collagen cross-links remained unchanged after spaceflight. Bone lengths, cortical and endosteal areas, and regional thicknesses showed no significant differences between flight animals and ground controls. Our findings suggest that responsiveness of cortical bone to microgravity is less pronounced in adult rats than in previous spaceflight experiments in which young growing animals were used. We hypothesize that 14 days of spaceflight may not be sufficient to impact the biochemical and biomechanical properties of cortical bone in the mature rat skeleton.
authors.affiliation: Biodynamics Laboratory, University of Wisconsin-Madison 53792.
authors.forename: A C
authors.initials: AC
authors.lastname: Vailas
authors.forename: R
authors.initials: R
authors.lastname: Vanderby
authors.forename: D A
authors.initials: DA
authors.lastname: Martinez
authors.forename: R B
authors.initials: RB
authors.lastname: Ashman
authors.forename: M J
authors.initials: MJ
authors.lastname: Ulm
authors.forename: R E
authors.initials: RE
authors.lastname: Grindeland
authors.forename: G N
authors.initials: GN
authors.lastname: Durnova
authors.forename: A
authors.initials: A
authors.lastname: Kaplansky
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000818:Animals; D001842:Bone and Bones / Q000033:anatomy & histology / Q000378:metabolism / Q000502:physiology*; D006811:Humerus / Q000033:anatomy & histology / Q000378:metabolism / Q000502:physiology; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013026:Space Flight; D013048:Specimen Handling; D014465:Ultrasonics; D014893:Weightlessness / Q000009:adverse effects