title: [Low-frequency pulsed electromagnetic fields promotes rat osteoblast differentiation in vitro through cAMP/PKA signal pathway].
abstract: OBJECTIVE
  To study whether low-frequency pulsed electromagnetic fields promotes the differentiation of cultured rat osteoblasts through the cAMP/PKA signal pathway.
  
  
  METHODS
  Rat calvarial osteoblasts isolated by enzyme digestion were exposed to 50 Hz 0.6 mT low-frequency pulsed electromagnetic field for varying lengths of time, and the concentration of cAMP and levels of phosphorylated PKA in the cells were assayed. In cells treated with DDA to inhibit the activity of adenylate cyclase, the changes of ALP activity and transcription of osteogenic gene were detected after exposure to low-frequency pulsed electromagnetic field. The changes of osteogenic gene transcription and protein expression were tested in the osteoblasts pretreated with KT5720 in response to low-frequency pulsed electromagnetic field exposure.
  
  
  RESULTS
  The intracellular cAMP concentration in the cells increased significantly at 20 min during exposure to low-frequency pulsed electromagnetic field, began to decrease at 40 min during the exposure, and increased again after a 2-h exposure; the same pattern of variation was also observed in p-PKA level. Application of DDA and KT5720 pretreatment both suppressed the increase in ALP activity and osteogenic gene transcription induced by electromagnetic field exposure.
  
  
  CONCLUSIONS
  Low- frequency pulsed electromagnetic field exposure improves the differentiation of cultured rat osteoblasts by activating cAMP/PKA signal pathway.
authors.affiliation: Institute of Orthopedics, Lanzhou General Hospital of PLA, Lanzhou 730050, China.E-mail: qingqinggslz@126.com.
authors.forename: Qing-Qing
authors.initials: QQ
authors.lastname: Fang
authors.forename: Zhi-Zhong
authors.initials: ZZ
authors.lastname: Li
authors.forename: Jian
authors.initials: J
authors.lastname: Zhou
authors.forename: Wen-Gui
authors.initials: WG
authors.lastname: Shi
authors.forename: Juan-Li
authors.initials: JL
authors.lastname: Yan
authors.forename: Yan-Fang
authors.initials: YF
authors.lastname: Xie
authors.forename: Ke-Ming
authors.initials: KM
authors.lastname: Chen
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004574:Electromagnetic Fields; D010006:Osteoblasts / Q000166:cytology*; D010012:Osteogenesis; D051381:Rats; D015398:Signal Transduction
chemical_list: D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases