Large gradient high magnetic field affects FLG29.1 cells differentiation to form osteoclast-like cells.
OBJECTIVE
We aimed to investigate the effects of different apparent gravities (μ g, 1 g and 2 g) produced by large gradient high magnetic field (LGHMF) on human preosteoclast FLG29.1 cells.


METHODS
FLG29.1 cells were cultured in Roswell Park Memorial Institute (RPMI)-1640 medium. Cells were exposed to LGHMF for 72 h. On culture day 1, 2, 3, cell proliferation was detected by 3-(4,5)-dimethylthiahi-azo (-z-y1)-3,5-di-phenytetrazoliumromide (MTT) method. On day 3, cell apoptosis and necrosis were assayed by Hoechst and propidium iodide (PI) staining. After cells were exposed to LGHMF for 72 h with the induction of 12-o-tetradecanoylphorbol 13-acetate (TPA), Tartrate-Resistant Acid Phosphatase (TRAP) positive cells and nitric oxide (NO) release were detected by TRAP staining and Griess method, respectively. Intracellular TRAP activity was measured using nitrophenylphosphate (pNPP) as the substrate.


RESULTS
MTT detection revealed that compared to control, FLG 29.1 cell proliferation in the μ g and 2 g groups were promoted. However, there is no obvious difference between the 1 g and control groups. Hoechst-PI staining showed that LGHMF promoted cell apoptosis and necrosis, especially in the 2 g group. Exposure to LGHMF inhibited the NO concentration of supernatant. Both the TRAP activity and the number of TRAP positive cells were higher in cells of μ g group than those in 2 g group. In the 1 g group, they were decreased significantly compared to control.


CONCLUSIONS
These findings indicate that LGHMF could directly affect human preosteoclast FLG29.1 cells survival and differentiation. High magnetic flux inhibited osteoclasts formation and differentiation while reduced apparent gravity enhanced osteoclastogenesis.
Key Laboratory for Space Bioscience & Biotechnology, Institute of Special Environmental Biophysics, School of Life Science, Northwestern Polytechnical University, Xi'an, Shaan Xi Province, PR China.
Shengmeng
S
Di
Zongcheng
Z
Tian
Airong
A
Qian
Jingbao
J
Li
Jiawei
J
Wu
Zhe
Z
Wang
Dayu
D
Zhang
Dachuan
D
Yin
Maria Luisa
ML
Brandi
Peng
P
Shang
D002454:Cell Differentiation / Q000502:physiology* / Q000528:radiation effects; D002460:Cell Line; D004307:Dose-Response Relationship, Radiation; D000091344:Filaggrin Proteins; D006801:Humans; D060526:Magnetic Fields; D040542:Mechanotransduction, Cellular / Q000502:physiology* / Q000528:radiation effects; D010010:Osteoclasts / Q000166:cytology* / Q000502:physiology* / Q000528:radiation effects; D011829:Radiation Dosage; D013234:Stem Cells / Q000166:cytology* / Q000502:physiology* / Q000528:radiation effects; D018474:Weightlessness Simulation / Q000379:methods*