title: [Effects on rats' bone mineral density and bone biomechanics by suspensory simulated weightlessness and removing suspension].
abstract: OBJECTIVE
  To study the effects on rats' bone mineral density and bone biomechanics by suspensory simulated weightlessness and removing suspension.
  
  
  METHODS
  Twenty Wistar rats were divided into two groups randomly as control group and model group. Suspend the model group rats for 14 days, then remove suspension and continue to feed for another 14 days. Feed control group rats for 28 days. Detect the bone mineral density (BMD) in vivo of cranial bone, second thoracic vertebra, fourth lumbar vertebra, pelvis, right radioulna and right femoral bone of each group at the 14th day. At the 28th day,execute all the rats and take out of right femoral bone and fourth lumbar vertebra for detecting BMD and the intensity of biomechanics.
  
  
  RESULTS
  At the 14th day in experiment, being compared with control group,the BMD of femoral bone, pelvis and lumbar vertebra in model group decreased significantly (P < 0.001, P < 0.001, P < 0.01) and the change of BMD of cranial bone, thoracic vertebra and radioulna in model group was not remarkable (P > 0.05). At the 28th day in experiment, the BMD of femoral bone and lumbar vertebra, the maximal load of femoral bone decreased significantly in model group as compared with control group (P < 0.01, P < 0.001, P < 0.01).
  
  
  CONCLUSIONS
  BMD in vive body showed that suspensory simulated weightlessness for 14 days could cause disorder of bone metabolism and remarkable mineral loss of weight bearing bone, even BMD and biomechanical intensity of weight bearing bone decrease obviously when removing suspension for 14 days. The results suggest that the disorder of bone metabolism could not be recovered in short time.
authors.affiliation: Laboratory of the TCM, Preclinical Medical College of Beijing University of TCM, Beijing 100029, China.
authors.forename: Hai-ying
authors.initials: HY
authors.lastname: Tong
authors.forename: Su-min
authors.initials: SM
authors.lastname: Hu
authors.forename: Peng
authors.initials: P
authors.lastname: Zhou
authors.forename: Qian
authors.initials: Q
authors.lastname: Fu
authors.forename: Jin
authors.initials: J
authors.lastname: Li
authors.forename: Xue-min
authors.initials: XM
authors.lastname: Gao
authors.forename: Jian-jun
authors.initials: JJ
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D015519:Bone Density; D001842:Bone and Bones / Q000502:physiology*; D019417:Hindlimb Suspension; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D018474:Weightlessness Simulation