Medical/biological study (experimental study)

Combined effects of flow-induced shear stress and electromagnetic field on neural differentiation of mesenchymal stem cells med./bio.

By: Mascotte-Cruz JU, Rios A, Escalante B

Published in: Electromagn Biol Med 2016; 35 (2): 161-166

Aim of study (acc. to author)

The effects of co-exposure of rat bone marrow-derived mesenchymal stem cells to a 60 Hz magnetic field and flow-induced shear stress on neural differentiation should be investigated.

Background/further details

Individual exposure to flow-induced shear stress (mechanical stress) or magnetic fields have shown to be beneficial in neural differentiation of cells (see Cho et al. 2012 and Kim et al. 2013). However, a combination of both measures has not been investigated to date and the authors supposed a synergistic effect of co-exposure.
Cells were divided into the following groups: 1) co-exposure to the magnetic field and flow-induced shear stress, 2) exposure to the magnetic field, 3) exposure to flow-induced shear stress, 4) control group.
After exposure, cells were re-cultured and investigated after 1 hour, 9 hours, 1 day, 3 days and 6 days of incubation.

Endpoint

cell viability/cell division/proliferation: neural differentiation of rat bone marrow-derived mesenchymal stem cells

Exposure

- 60 Hz
- 50/60 Hz
- magnetic field
- also other exposures without EMF
- co-exposure

Exposure	Parameters
Exposure 1: 60 Hz Exposure duration: continuous for 1 hour	magnetic flux density: 17.01 mT

General information

fluid shear stress in groups 1 and 3 was 15 dynes/cm²

Exposure 1

Main characteristics

Frequency	60 Hz
Type	magnetic field
Waveform	sinusoidal
Exposure duration	continuous for 1 hour

Exposure setup

Exposure source	solenoid
Setup	solenoid had a length of 10 cm, 400 loops and a radius of 2.5 cm; it was placed into a water jacket to maintain constant temperature of 37°C; system was combined with shear force system and cells flowed constantly through a microfluidic chamber placed on top of the solenoid

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	17.01 mT	-	measured	-	-

Additional parameter details

no electric emission from solenoid was detected

Exposed system:

intact cell/cell culture
rat bone marrow-derived mesenchymal stem cells

Methods Endpoint/measurement parameters/methodology

cell viability/cell division/proliferation: neural differentiation: cell morphology (only after 6 days, light microscopy); protein expression of nestin (neuronal precursor marker) and CD31 (marker of endothelial cells) (immunohistochemical stain with Alexa Fluor 488 and DAPI, confocal microscopy)

Investigated system:

intact cell/cell culture

Time of investigation:

after exposure

Main outcome of study (acc. to author)

Cells either exposed to the magnetic field (group 2) or flow-induced shear stress (group 3) as well as cells from the control group (group 4) showed a flattened, spindleshaped and fibroblast-like morphology. By contrast, in the co-exposure group (group 1), some cells exhibited narrow, elongated, neurite-like branches, i.e. a neural phenotype.
The nestin protein expression was significantly increased in group 1 compared to the control group 1, 3 and 6 days after exposure. All other groups showed only a scarce nestin protein expression. CD31 was only expressed in 1% of all cells in group 1, indicating that there were almost no endothelial cells present.
The authors conclude that co-exposure of rat bone marrow-derived mesenchymal stem cells to a 60 Hz magnetic field and flow-induced shear stress might have a synergistic effect which promotes neural differentiation.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

not stated/no funding

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