title: Different electromagnetic field waveforms have different effects on proliferation, differentiation and mineralization of osteoblasts in vitro.
abstract: Noninvasive electromagnetic fields (EMFs) have been known to be able to improve bone health; however, their optimal application parameters and action mechanisms remain unclear. This study compared the effects of different forms of EMFs (sinusoidal, triangular, square, and serrated, all set at 50 Hz frequency and 1.8 mT intensity) on proliferation, differentiation and mineralization of rat calvarial osteoblasts. Square EMFs stimulated osteoblast proliferation but sinusoidal EMFs inhibited it. Sinusoidal and triangular EMFs produced significantly greater alkaline phosphatase (ALP) activity, ALP staining areas, calcium deposition, mineralized nodule areas, and mRNA expression of Runx-2, osteoprotegerin and insulin-like growth factor-I than square and serrated EMFs (P < 0.01). Triangular EMFs had a greater effect than sinusoidal EMFs on every indices except for Runx-2 mRNA expression (P < 0.05). These results indicated that while square EMFs promoted proliferation and had no effect on the differentiation of osteoblasts, sinusoidal EMFs inhibited proliferation but enhanced osteogenic differentiation. Triangular EMFs did not affect cell proliferation but induced the strongest osteogenic activity among the four waveforms of EMFs. Thus, the effects of EMFs on proliferation and differentiation of osteoblasts in vitro were dependent on their waveforms.
authors.affiliation: Institute of Orthopaedics, Lanzhou General Hospital, Lanzhou Command of People's Liberation Army, Lanzhou, P.R., China.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhou
authors.forename: Jia-Qi
authors.initials: JQ
authors.lastname: Wang
authors.forename: Bao-Feng
authors.initials: BF
authors.lastname: Ge
authors.forename: Xiao-Ni
authors.initials: XN
authors.lastname: Ma
authors.forename: Hui-Ping
authors.initials: HP
authors.lastname: Ma
authors.forename: Cory J
authors.initials: CJ
authors.lastname: Xian
authors.forename: Ke-Ming
authors.initials: KM
authors.lastname: Chen
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D002113:Calcification, Physiologic / Q000502:physiology / Q000528:radiation effects*; D002118:Calcium / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology / Q000528:radiation effects*; D049109:Cell Proliferation / Q000502:physiology / Q000528:radiation effects*; D002478:Cells, Cultured; D050659:Core Binding Factor Alpha 1 Subunit / Q000378:metabolism; D004574:Electromagnetic Fields; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D010006:Osteoblasts / Q000502:physiology / Q000528:radiation effects*; D010012:Osteogenesis / Q000502:physiology / Q000528:radiation effects; D053244:Osteoprotegerin / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D017208:Rats, Wistar
chemical_list: D050659:Core Binding Factor Alpha 1 Subunit; D053244:Osteoprotegerin; D012333:RNA, Messenger; C493717:Runx2 protein, rat; C506032:Tnfrsf11b protein, rat; C548904:insulin-like growth factor-1, rat; D007334:Insulin-Like Growth Factor I; D000469:Alkaline Phosphatase; D002118:Calcium
keywords: differentiation; electromagnetic fields; osteoblasts; proliferation; waveforms