title: [Effects of simulated weightlessness on ALP, ACP, collagen I, and biomechanics of hind-limb bones in rats].
abstract: OBJECTIVE
  To investigate effects of 3 weeks simulated weightlessness on biomechanical parameters, alkaline phosphatase (ALP), acid phosphatase (ACP) and collagen I of hind-limb bones in tail-suspended rats.
  
  
  METHODS
  Fourteen male SD rats were divided equally into control group (CON) and experimental group; tail-suspended (TS) was used to simulate weightlessness. After 3 weeks tail-suspension, biomechanical parameters of femur were measured; ALP, ACP and collagen I of tibia were observed.
  
  
  RESULTS
  Elastic load, maximum load, and bending rigidity coefficient decreased significantly (P<0.01), while the maximum deformation and bending toughness coefficient increased markedly (P<0.01 or P<0.05). Morphological results showed that ALP declines significantly in TS group, ACP and type I collagen increased significantly in TS group.
  
  
  CONCLUSIONS
  After tail-suspension for 3 weeks, growth of rat's weight bearing bones are suppressed, biomechanical capability declines, and collagen I metabolism becomes disordered.
authors.affiliation: caoxinsheng@top.com
authors.forename: Xin-sheng
authors.initials: XS
authors.lastname: Cao
authors.forename: Xing-yu
authors.initials: XY
authors.lastname: Wu
authors.forename: Yan-hong
authors.initials: YH
authors.lastname: Wu
authors.forename: Lian-jia
authors.initials: LJ
authors.lastname: Yang
authors.forename: Li-fan
authors.initials: LF
authors.lastname: Zhang
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism*; D000469:Alkaline Phosphatase / Q000378:metabolism*; D000818:Animals; D001696:Biomechanical Phenomena; D024042:Collagen Type I / Q000378:metabolism*; D005269:Femur / Q000254:growth & development; D019417:Hindlimb Suspension; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D016474:Weight-Bearing; D018474:Weightlessness Simulation
chemical_list: D024042:Collagen Type I; D000469:Alkaline Phosphatase; D000135:Acid Phosphatase