title: Combined effects of 50 Hz magnetic field and magnetic nanoparticles on the proliferation and apoptosis of PC12 cells.
abstract: OBJECTIVE
  To investigate the bioeffects of extremely low frequency (ELF) magnetic field (MF) (50 Hz, 400 μT) and magnetic nanoparticles (MNPs) via cytotoxicity and apoptosis assays on PC12 cells.
  
  
  METHODS
  MNPs modified by SiO₂ (MNP-SiO₂) were characterized by transmission electron microscopy (TEM), dynamic light scattering and hysteresis loop measurement. PC12 cells were administrated with MNP-SiO2 with or without MF exposure for 48 h. Cytotoxicity and apoptosis were evaluated with MTT assay and annexin V-FITC/PI staining, respectively. The morphology and uptake of MNP-SiO₂ were determined by TEM. MF simulation was performed by Ansoft Maxwell based on the finite element method.
  
  
  RESULTS
  MNP-SiO₂ were identified as ~20 nm (diameter) ferromagnetic particles. MNP-SiO₂ reduced cell viability in a dose-dependent manner. MF also reduced cell viability with increasing concentrations of MNP-SiO₂. MNP-SiO₂ alone did not cause apoptosis in PC12 cells; instead, the proportion of apoptotic cells increased significantly under MF exposure and increasing doses of MNP-SiO₂. MNP-SiO₂ could be ingested and then cause a slight change in cell morphology.
  
  
  CONCLUSIONS
  Combined exposure of MF and MNP-SiO₂ resulted in remarkable cytotoxicity and increased apoptosis in PC12 cells. The results suggested that MF exposure could strengthen the MF of MNPs, which may enhance the bioeffects of ELF MF.
authors.affiliation: Beijing Key Laboratory of Bioelectromagnetism, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Hong Li
authors.initials: HL
authors.lastname: Jia
authors.affiliation: Beijing Key Laboratory of Bioelectromagnetism, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China; Department of Basic Theory, Shandong Sport University, Jinan 250102, Shandong, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Wang
authors.affiliation: Beijing Key Laboratory of Bioelectromagnetism, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Li
authors.affiliation: Beijing Key Laboratory of Bioelectromagnetism, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Beijing Key Laboratory of Bioelectromagnetism, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Ping Ping
authors.initials: PP
authors.lastname: Wang
authors.affiliation: Beijing Key Laboratory of Bioelectromagnetism, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Wei Dong
authors.initials: WD
authors.lastname: Pan
authors.affiliation: Beijing Key Laboratory of Bioelectromagnetism, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Song
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects*; D060526:Magnetic Fields / Q000009:adverse effects*; D058185:Magnetite Nanoparticles / Q000633:toxicity*; D046529:Microscopy, Electron, Transmission; D016716:PC12 Cells; D051381:Rats; D012822:Silicon Dioxide
chemical_list: D058185:Magnetite Nanoparticles; D012822:Silicon Dioxide
keywords: Apoptosis; Cytotoxicity; Extremely low frequency magnetic field; Magnetic nanoparticles; Morphology