title: Effect of sinusoidal electromagnetic field on bone mineral density and histomorphometry of rats at different time points.
abstract: OBJECTIVE
  To investigate the effect of 50 Hz 0.1 mT sinusoidal electromagnetic field at different time points on bone mineral density(BMD)and histomorphometry in rats.
  
  
  METHODS
  Totally 50 6-week-old female SD rats were equally randomized into 5 groups: control group,45-minute group,90-minute group,180-minute group,and 270-minute group. Except for the control group,the other four groups were given magnetic intervention in the 50-Hz 0.1-mT sinusoidal electromagnetic field for 45 minutes,90 minutes,180 minutes,or 270 minutes,respectively,on a daily basis. After 8 weeks,the total body BMD,femur BMD,and vertebral BMD were measured by dual-energy X-ray absorptiometry. The left tibia and the fifth lumbar vertebrae were separated for bone tissue static and dynamic analyses.
  
  
  RESULTS
  Compared with control group,the 90-minute group and the 180-minute group had significantly different total body BMD(P<0.01,P<0.05),while no such significant difference was seen in the 45-minute group and 270-minute group (P>0.05). The femur,vertebral BMD,serum biochemical markers,and the static parameters of the fifth lumbar vertebrae tissue showed significant differences in the 90-minute group,180-minute group,and 270-minute group(P<0.01),but not in the 45-minute group (P>0.05). As shown by double fluorescent labeling,the distance was sorted in an order of 90-minute group>180-minutes group>270-minute group>45-minutes group>control group.
  
  
  CONCLUSIONS
  The 50-Hz 0.1-mT sinusoidal electromagnetic field can effectively increase bone mineral density and improve bone morphology;however,the intervention effectiveness differs at different time points,with the best effectiveness seen at 90 minutes.
authors.affiliation: Institute of Orthopaedics,Lanzhou General Hospital of Lanzhou Military Area Command of Chinese PLA,Lanzhou 730050,China.
authors.forename: Yu-Hai
authors.initials: YH
authors.lastname: Gao
authors.affiliation: Institute of Orthopaedics,Lanzhou General Hospital of Lanzhou Military Area Command of Chinese PLA,Lanzhou 730050,China.
authors.forename: Ping
authors.initials: P
authors.lastname: Zhen
authors.affiliation: Institute of Orthopaedics,Lanzhou General Hospital of Lanzhou Military Area Command of Chinese PLA,Lanzhou 730050,China.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhou
authors.affiliation: Institute of Orthopaedics,Lanzhou General Hospital of Lanzhou Military Area Command of Chinese PLA,Lanzhou 730050,China.
authors.forename: Xiao-Ni
authors.initials: XN
authors.lastname: Ma
authors.affiliation: Institute of Orthopaedics,Lanzhou General Hospital of Lanzhou Military Area Command of Chinese PLA,Lanzhou 730050,China.
authors.forename: Juan-Li
authors.initials: JL
authors.lastname: Yan
authors.affiliation: Institute of Orthopaedics,Lanzhou General Hospital of Lanzhou Military Area Command of Chinese PLA,Lanzhou 730050,China.
authors.forename: Shao-Feng
authors.initials: SF
authors.lastname: Li
authors.affiliation: Institute of Orthopaedics,Lanzhou General Hospital of Lanzhou Military Area Command of Chinese PLA,Lanzhou 730050,China.
authors.forename: Yan-Feng
authors.initials: YF
authors.lastname: Zhou
authors.affiliation: Institute of Orthopaedics,Lanzhou General Hospital of Lanzhou Military Area Command of Chinese PLA,Lanzhou 730050,China.
authors.forename: Ke-Ming
authors.initials: KM
authors.lastname: Chen
mesh_terms: D015502:Absorptiometry, Photon; D000818:Animals; D015519:Bone Density; D001842:Bone and Bones; D004574:Electromagnetic Fields; D005260:Female; D005269:Femur; D008159:Lumbar Vertebrae; D051381:Rats; D017207:Rats, Sprague-Dawley; D013977:Tibia