Static electric fields interfere in the viability of cells exposed to ionising radiation

Abstract

Application of an EF following irradiation greatly increases cell death. The observation that the DNA repair shoulder in the survival curve of C. albicans is suppressed when cells are exposed to irradiation + EF suggests that EF likely inactivate cellular recovering processes. The result for the number of nuclei with gamma-H2AX foci in MRC5 cells indicates that an EF interferes mostly in the DNA repair mechanisms. A molecular ad-hoc model is proposed.

Sensing Of DNA Damage, Instantly Activation of Repairing Proteins and Radio Sensitizers-A Biophysical Model

“…A series of experiments was carried out at this Laboratory with prokaryotes and eukaryotes exposed to ionizing radiation and exogenous static electric fields. [22][23][24][25] All results show that when cells exposed to radiation are immediately submitted to static electric fields, cell death increases enormously compared to the effect of radiation alone. Since the sole application of an electric (E) field has no effect on control samples, it was thus demonstrated that the E-field acts on the DNA repair process.…”

“…These results indicate that static electric fields directly interfere in DNA repair mechanisms by inactivating cellular DNA repair processes, as revealed by the 40% surplus of nuclei with γ-H2AX foci in MRC5 cells. 22 Highly revealing too, Moron et al, 25 at this Laboratory, irradiated T47D breast cancer cells with 1 and 2Gy of gamma radiation, and then exposed them to a static electric field of 1250V/cm by 24hours. From cell cycle distributions evaluation by flow cytometry, it was found that treatment with irradiation and a static electric field (SEF) exposure causes a higher accumulation of cells at the S phase, and a corresponding reduction at G1, while the population in G2/M remained nearly unchanged.…”

“…The limits of this radio sensitization process induced by SEFs were tested by carrying out viability measurements with highly radioresistant cell lines, such as Deinococcus radiodurans, one of the fiercest radioresistant organisms, exhibiting a sophisticated repair mechanism responsible for its extremophilic character. 22,24 It should be noted that the present approach, using long-range electron transfer and conduction in DNA (Appendix 1) is high on the agenda of many biochemistry and biophysics research groups, as evidenced by a Special Issue section in PNAS-102-see, in particular. [30][31][32] The hypothesis here developed, by constituting a reasonable guideline for more elaborated signaling/transduction models, is also an original and effective contribution to the research field on cellular responses to genomic insult.…”

Estudo da ação combinada de radiações ionizantes com campos elétricos e magnéticos em cianobactérias - viabilidade celular e atenuação de toxinas.

“…A radiossensibilidade de algumas cianobactérias vem sendo estudada há algumas décadas apenas para a radiação gama (ARRUDA-NETO et al, 2009;ASATO, 1971;BILLI et al, 2000;CAVALCANTE-SILVA et al, 2011;HEREMAN et al, 2007;KRAUS, 1969;POSNER;SPARROW, 1963). Doses utilizadas para matar cianobactérias são consideradas altas quando comparadas com outros organismos procariotos.…”

“…quando aplicados separadamente em microrganismos. Porém, a utilização simultânea eficaz de dois ou mais desses agentes físicos foi muito pouco estudada (ARRUDA-NETO et al, 2009;GRANT;PATTERSON, 1995;HEREMAN et al, 2007;ROGOVSCHI et al, 2007;SHAMSUZZAMAN, 1988;TAGHIPOUR, 2004). Há um aumento do número de estudos que objetivam a alteração do crescimento, morfologia, fotossíntese e danos ao DNA, entre outros, em cianobactérias, através de efeitos combinados de agentes físicos (AGARWAL, 2008;ARRUDA-NETO et al, 2009;BROWN, 2007;GAO et al 2008;HEREMAN, 2007).…”