title: [Precision of rat BMD measurements by dual-energy X-ray absorptiometry in vitro].
abstract: OBJECTIVE
  To evaluate the precision of rat bone mineral density (BMD) measurements by Norland Excellplus dual-energy X-ray absorptiometry (DXA) and to investigate the BMD changes in ovariectomized (Ovx) rats in vitro.
  
  
  METHODS
  (1) The coefficients of variation (CV) for BMD measurements at various skeletal regions were repeatedly determined by DXA in 10 Wistar rats in vitro. (2) BMD in lumbar vertebra (L5) and both sides of femurs was measured in total 90 rats. And (3) changes in BMD between Ovx and sham rats were compared.
  
  
  RESULTS
  (1) The short-term CVs of BMD measurements in different regions by DXA were as follows, 1.58% for lumbar vertebra (L5), 0.90% for left femur, and 0.86% for right femur, respectively. The long-term CVs were 2.22% for lumbar vertebra (L5), 1.09% for left femur, and 1.20% for right femur. (2) The BMD values in 90 Wistar rats were (127.5 +/- 12.3) in lumbar vertebra (L5), (82.6 +/- 11.3) in corpus vertebra (L5'), (150.7 +/- 10.6) in left femur and (149.9 +/- 10.6) mg/cm2 in right femur, respectively. The correlation coefficient of BMD measurements between left and right femurs was 0.792 (P < 0.001). (3) In Ovx group, the BMD values of corpus vertebra (L5') and distal femurs were significantly decreased, that was 10.0%-17.5% lower in comparison with sham group (P < 0.001).
  
  
  CONCLUSIONS
  Measurement of rat BMD in vitro by Norland Excellplus DXA is a useful method, and it can reflect the changes in rat bone masses with good precision.
authors.affiliation: Department of Endocrinology, PUMC Hospital, CAMS and PUMC, Beijing 100730, China.
authors.forename: Xiao-ping
authors.initials: XP
authors.lastname: Xing
authors.forename: Xun-wu
authors.initials: XW
authors.lastname: Meng
authors.forename: Zhi-qiang
authors.initials: ZQ
authors.lastname: Cheng
authors.forename: Zhi-wei
authors.initials: ZW
authors.lastname: Zhan
authors.forename: Zhi-hui
authors.initials: ZH
authors.lastname: Chui
authors.forename: Wei-bo
authors.initials: WB
authors.lastname: Xia
authors.forename: Xue-ying
authors.initials: XY
authors.lastname: Zhou
mesh_terms: D015502:Absorptiometry, Photon; D000818:Animals; D015519:Bone Density; D005260:Female; D066298:In Vitro Techniques; D010052:Ovariectomy; D051381:Rats; D017208:Rats, Wistar