Effects of a pulsed electromagnetic field on cell proliferation, differentiation and osterix mRNA expression in rat osteoblasts / 中华物理医学与康复杂志

ABSTRACT

Objective To investigate the effects of a pulsed electromagnetic field (PEMF) on cell proliferation,differentiation and the genetic expression of osteogenesis specific transcription factor-Osterix (OSX) in the calvaria-derived osteoblasts of SD rats.MethodsPrimary osteoblasts were separated from the calvarias of Sprague-Dawley rats 24 hours after birth by trypsinazation and collagenase digestion.The osteoblasts at passage 4 were randomly divided into a control group and a PEMF group,Cells in the PEMF group were placed onto PEMF therapeutic apparatus and exposed to 11 mT radiation at 12 Hz for 1 h per day for 3 days.The osteoblasts' proliferation ability was then detected via methylthiazdyl tetrazolium assay.Alkaline phosphatase (ALP) activity in the cell lysate and the supernatant fluid was assayed through disodium phenyl phosphate colorimetric determination to determine the cells'differentiation ability.OSX mRNA expression was determined using real time reverse transcription polymerase chain reaction (RT-PCR).ResultsThe proliferation of osteoblasts in the PEMF group was significantly greater than in the control group.PEMF exposure suppressed ALP activity in both the lysate and the supernatant of the osteoblasts.The OSX mRNA expression in the PEMF group was significantly down-regulated compared with the control group.ConclusionPEMF at 12 Hz and 11 mT can promote the proliferation of osteoblasts,but it inhibits cellular differentiation and down-regulates the mRNA expression of OSX.