The Frequency of a Magnetic Field Determines the Behavior of Tumor and Non-Tumor Nerve Cell Models

Abstract

The involvement of magnetic fields in basic cellular processes has been studied for years. Most studies focus their results on a single frequency and intensity. Intensity has long been the central parameter in hypotheses of interaction between cells and magnetic fields; however, frequency has always played a secondary role. The main objective of this study was to obtain a specific frequency that allows a reduction in the viability and proliferation of glioblastoma (CT2A) and neuroblastoma (N2A) cell models. These were compared with an astrocyte cell model (C8D1A) (nontumor) to determine whether there is a specific frequency of response for each of the cell lines used. The CT2A, C8D1A, and N2A cell lines were exposed to a magnetic field of 100 µT and a variable frequency range between 20 and 100 Hz for 24, 48 and 72 h. The results fit a biological window model in which the viability and proliferation of N2A and CT2A cells decrease statistically significantly in a 50 Hz center of value window. In addition, the non-tumor cell model showed different behavior from tumor cell models depending on the applied frequency. These results are promising in the use of magnetic fields for therapeutic purposes.

Keywords: astrocytes; biological window; frequency; glioblastoma; magnetic field; neuroblastoma; proliferation; viability.

Figure 1

Percentage of viability obtained in the different frequency ranges tested, [20–100; 20] Hz (A,D,G), [20–60; 10] Hz (B,E,H) and [40–60; 5] Hz (C,F,I) of the different nerve tissue cell lines tested with respect to non-exposure controls. A, B, C: glioblastoma model (CT2A), (D–F): neuroblastoma model (N2A) and (G–I): astrocyte model (C8D1A). All assays are performed at a fixed intensity of 100 µT at 24, 48 and 72 h of exposure. Statistical results of application of the t-Student or U-Mann–Whitney statistical test with 95%-CI according to normality of the data (*) p-value < 0.05; (**) p-value < 0.001; (n.s.) non-significant.

Figure 2

(A): Percentage of proliferation of the different nerve tissue cell lines tested with respect to non-exposure controls. (B): Percentage of dead cells with respect to non-exposure controls. It should be noted that 0 Hz represents the no-exposure controls. All tests are performed at frequencies of 45, 50 and 55 Hz with a fixed intensity of 100 µT in 24 h of exposure. Statistical results of the application of the Student’s t-test or Mann–Whitney U statistical test are presented with 95–CI according to the normality of the data. (*) p-value < 0.05; (**) p-value < 0.001; (n.s.) non-significant.

Figure 3

Apoptosis assay results at different frequencies of 45 Hz (B,F,J), 50 Hz (C,G,K) and 55 Hz (D,H,L) for CT2A (A–D), N2A (E–H) and C8D1A (D,I–L) tumor cell line models. The results of viability (M), proliferation (N) and dead cells (O) are presented. Statistical results of the application of Student’s t-test or Mann–Whitney U statistical test with 95–CI according to normality of the data: (*) p-value < 0.05; (**) p-value < 0.001; (n.s.) non-significant.

Figure 4

Image of the RILZ coil system used for cell experimentation.