The effects of exposure of mouse embryonic neural stem cells to a 50 Hz magnetic field on neuronal differentiation and development and the underlying molecular mechanisms of action should be investigated.
To investigate the role of TRPC1 ion channels, the TRPC1 translation was inhibited (a so called gene knockdown) via transfection with TRPC1-siRNA (small interfering RNA). TRPC1 is a calcium ion channel and the intracellular calcium level is believed to be associated with cell differentiation.
Results were obtained from five independent duplicate experiments.
Exposure duration: continuous for 4 h/day for 1, 2 or 3 days
|Exposure duration||continuous for 4 h/day for 1, 2 or 3 days|
|Chamber||two identical chambers placed inside a commercial incubator|
|Setup||environmental conditions in chambers were kept stable (37°C, 5% CO2, 95% humidity); the temperature variance between the chambers did not exceed 0.3°C; during exposure, the chambers were randomly assigned to sham exposure or exposure by a computer program|
|Sham exposure||A sham exposure was conducted.|
|magnetic flux density||1 mT||-||-||-||-|
Cell viability, cell maintenance, cell proliferation and gene expression of proliferation-related genes were significantly increased after exposure for 3 days compared to sham exposed cells.
Differentiation into neurons was significantly increased in exposed cells compared to sham exposed cells after 3 days, as shown by immunohistochemical stain, protein expression and gene expression of neuronal markers (NeuroD and Ngn1). Moreover, the length of neurites and the number of branch points was significantly increased in exposed cells in comparison to sham exposed cells.
Exposure to the magnetic field had no effect on apoptosis.
The magnetic field exposure led to a significantly increased TRPC1 gene expression and protein expression (no differences were observed for TRPC3-7) and to a significantly increased intracellular calcium peak level after 3 days compared to the sham exposure. However, in cells with TRPC1 knockdown, the effects of the magnetic field on neuronal differentiation and the calcium level were reversed.
The authors conclude that exposure of mouse embryonic neural stem cells to a 50 Hz magnetic field might stimulate proliferation and neuronal differentiation via upregulation of the expression of TRPC1 and neuronal genes (NeuroD and Ngn1).