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Electromagnetic fields at the mobile phone frequency (900 MHz) trigger the onset of the general stress response along with DNA modifications in Eisenia fetida earthworms

Eisenia fetida earthworms were exposed to electromagnetic field (EMF) at the mobile phone frequency (900 MHz), and at field levels ranging from 10 to 120 V m‐1 for a period of 2 h. Potential effects of longer exposure (4 h), field modulation, and recovery period of 24 h after 2 h of exposure were addressed at the field level of 23 V m‐1 . All exposure treatments induced significant DNA modifications as assessed by a quantitative random amplified polymorphic DNA‐ PCR. Even after 24 h of recovery following a 2 h exposure, the number of probe hybridization sites displayed a significant 2‐fold decrease as compared to untreated control earthworms, implying a loss of hybridization sites. Expression of genes involved in the response to general stress (HSP70 and MEKK1, the latter involved in signal transduction), oxidative stress (CAT, encoding catalase), chemical and immune defence (LYS, encoding lysenin, and MYD, encoding a myeloid differentiation factor) were up regulated after exposure to 10 and modulated 23 V m‐1 field levels. Western blots showing an increased quantity of HSP70 and MTCO1 proteins confirmed this stress response (MTCO1 is the subunit 1 of cytochrome c oxidase, indicating a mitochondrial impact). HSP70 and LYS genes were found up regulated after 24 h of recovery following a 2 h exposure, meaning that the effect of EMF exposure lasted for hours.

DNA modifications; earthworm; exposure to electromagnetic field; stress; Western blotting

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