Study type:
Medical/biological study
(experimental study)
Differential effects of high and low strength magnetic fields on mouse embryonic development and vasculogenesis of embryonic stem cells
med./bio.
By:
Bekhite MM, Finkensieper A, Abou-Zaid FA, El-Shourbagy IK, El-Fiky NK, Omar KM, Sauer H, Wartenberg M
Published in: Reprod Toxicol 2016; 65: 46-58
Aim of study (acc. to author)
Background/further details
The study comprised an in vivo in vitro in vivo pregnant mice were divided into the following groups (n=10 for each method and time of investigation, total number unclear): exposure to a 1) 1 mT 50 Hz magnetic field , 2) 1 mT static magnetic field , 3) 10 mT 50 Hz magnetic field , 4) 10 mT static magnetic field and 5) sham exposure . Embryos were collected and examined after 5, 8, 12 and 20 days of exposure .pregnant mice were exposed to the same fields (n=10 each) but no detailed results were shown.in vitro aggregations of pluripotent mouse embryonic stem cells , were used as models for embryonic development and were exposed to the same fields: 6) 1 mT 50 Hz magnetic field , 7) 1 mT static magnetic field , 8) 10 mT 50 Hz magnetic field , 9) 10 mT static magnetic field and 10) sham exposure .in vitro cells were also treated with p38 MAPK , JNK and ERK -1/2 inhibitors and free radical scavengers to examine the signal pathways .
Endpoint
Exposure
Exposure
Parameters
Exposure 1:
50 Hz
Exposure duration:
8 hours/day for up to 20 days during
gestation
Exposure 2:
Exposure duration:
8 hours/day for up to 20 days during
gestation
Exposure 3:
50 Hz
Exposure duration:
8 hours/day for up to 20 days during
gestation
Exposure 4:
Exposure duration:
8 hours/day for up to 20 days during
gestation
Exposure 5:
50 Hz
Exposure 6:
Exposure 7:
50 Hz
Exposure 8:
Frequency
50 Hz
Type
Waveform
Exposure duration
8 hours/day for up to 20 days during gestation
Additional info
in vivo
Exposure source
Chamber
high enough cages made of dielectric , transparent plastic
Setup
ten mice were placed in 2 cages (5 mice per cage) in homogeneous field; coils were wound on tubes from polyvinylchloride (PVC), which shielded against emission of electric fields ; temperature changes in exposure chamber was 1°C ± 0.5°C
Sham exposure
A sham exposure was conducted.
Frequency
Type
Exposure duration
8 hours/day for up to 20 days during gestation
Additional info
in vivo
Frequency
50 Hz
Type
Waveform
Exposure duration
8 hours/day for up to 20 days during gestation
Additional info
in vivo
Frequency
Type
Exposure duration
8 hours/day for up to 20 days during gestation
Additional info
in vivo
Frequency
50 Hz
Type
Waveform
Exposure duration
8 hours/day from 2 to 8 during differentiation
Additional info
in vitro
Frequency
50 Hz
Type
Waveform
Exposure duration
8 hours/day from 2 to 8 during differentiation
Additional info
in vitro
Reference articles
Bekhite MM et al.
(2010):
Static electromagnetic fields induce vasculogenesis and chondro-osteogenesis of mouse embryonic stem cells by reactive oxygen species-mediated up-regulation of vascular endothelial growth factor
Extended view
Compact view
Methods
Endpoint/measurement parameters/methodology
molecular biosynthesis : protein expression of caspase -3 (marker for apoptosis ), vascular endothelial growth factor (VEGF) and Flk-1 (VEGF receptor ) (markers for embryonic development), ERK 1/2, JNK and p38 MAPK and platelet endothelial cell adhesion molecule -1 (PECAM-1, marker for blood vessel formation) in embryoid bodies and VEGF protein expression in liver , lung , kidney and eyes of fetuses after 20 days (immunofluorescence stain, fluorescence microscopy )effects on embryo /fetus : birth weight, crown-rump length (after 12 and 20 days), embryonal development (histological sections of uteri 5 and 8 days after conception ; hematoxylin-eosin stain , microscopy ), additionally, see "molecular biosynthesis " and "morphological /histopathological changes"
morphol./histopathol. changes: general histology of liver , lung , eye , ovary and uterus from fetuses and mothers after 20 days (percentages of abnormal organs , follicle count and number of implantation sites and resorbed /living/dead fetuses in uteri , hematoxylin-eosin stain , microscopy )
reactive oxygen species production in embryoid bodies (fluorescein stain, confocal microscopy ), body weight of mothers during exposure
Investigated system:
Investigated organ system:
Time of investigation:
during exposure
after exposure
Main outcome of study (acc. to author)
In the 10 mT static and 50 Hz magnetic field groups (groups 3 and 4), a significantly increased number of resorbed and dead fetuses , pronounced histological alterations, reduced blood vessel formation and a significantly reduced VEGF protein expression in all organs compared to the sham exposure group were found. Additionally, a significantly reduced crown-rump length and body weight of fetuses were found in group 4 compared to the sham exposure group after 20 days. This was not observed in 1 mT magnetic fields (groups 1 and 2) but instead, VEGF expression in the ovary was significantly increased compared to the sham exposure group.exposure to 10 mT static or 50 Hz fields (groups 8 and 9) significantly increased reactive oxygen species (6-fold increase) and apoptosis , while significantly decreasing the blood vessel formation and VEGF expression compared to the sham exposure group.exposure of embryoid bodies to 1 mT static or 50 Hz fields), reactive oxygen species were also significantly increased compared to the sham exposure group but only a 2-fold increase was measured, and the expression of VEGF was significantly increased.inhibitors showed that reactive oxygen species were involved in the magnetic field -induced signal transduction , which led to activation of VEGF.prenatal exposure of mice to high (10 mT) static or 50 Hz magnetic field might have adverse effects on the embryonic development. VEGF is possibly an important mediator in these effects.
Study funded by
Deutsche Forschungsgemeinschaft (DFG; German Research Foundation)
Ministry of Higher Education and Scientific Research, Arab Republic of Egypt
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