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

Abstract

Eisenia fetida earthworms were exposed to electromagnetic field (EMF) at a mobile phone frequency (900 MHz) and at field levels ranging from 10 to 120 V m-1 for a period of two hours (corresponding to specific absorption rates ranging from 0.13 to 9.33 mW kg-1). Potential effects of longer exposure (four hours), field modulation, and a recovery period of 24 h after two hours 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 two hour-exposure, the number of probe hybridisation sites displayed a significant two-fold decrease as compared to untreated control earthworms, implying a loss of hybridisation sites and a persistent genotoxic effect of EMF. Expression of genes involved in the response to general stress (HSP70 encoding the 70 kDa heat shock protein, and MEKK1 involved in signal transduction), oxidative stress (CAT, encoding catalase), and 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. HSP70 and LYS genes were up-regulated after 24 h of recovery following a two hour-exposure, meaning that the effect of EMF exposure lasted for hours.

AI evidence extraction

Main findings

Earthworms exposed to 900 MHz EMF at 10–120 V/m for 2 hours showed significant DNA modifications by quantitative RAPD-PCR across all exposure treatments. After 24 hours of recovery following a 2-hour exposure, probe hybridisation sites remained significantly decreased (~two-fold vs controls), and several stress/defence genes and proteins (including HSP70) were up-regulated, indicating a persistent stress response and genotoxic effect under the study conditions.

Outcomes measured

• DNA modifications/genotoxicity (RAPD-PCR; probe hybridisation sites)
• Gene expression changes: general stress response (HSP70, MEKK1)
• Gene expression changes: oxidative stress (CAT)
• Gene expression changes: chemical/immune defence (LYS, MYD)
• Protein expression changes (HSP70, MTCO1; Western blot)

Limitations

• Sample size not reported in abstract
• Exposure described in V/m; dosimetry details beyond reported SAR range not provided in abstract
• Outcomes are molecular/biomarker endpoints in earthworms; relevance to human health not addressed in abstract

Suggested hubs

• rf-genotoxicity (0.78)
  Reports significant DNA modifications/genotoxic effects after 900 MHz RF exposure in an animal model.

{
    "study_type": "animal",
    "exposure": {
        "band": "RF",
        "source": "mobile phone",
        "frequency_mhz": 900,
        "sar_wkg": null,
        "duration": "2 hours; also 4 hours; 24 h recovery after 2-hour exposure"
    },
    "population": "Eisenia fetida earthworms",
    "sample_size": null,
    "outcomes": [
        "DNA modifications/genotoxicity (RAPD-PCR; probe hybridisation sites)",
        "Gene expression changes: general stress response (HSP70, MEKK1)",
        "Gene expression changes: oxidative stress (CAT)",
        "Gene expression changes: chemical/immune defence (LYS, MYD)",
        "Protein expression changes (HSP70, MTCO1; Western blot)"
    ],
    "main_findings": "Earthworms exposed to 900 MHz EMF at 10–120 V/m for 2 hours showed significant DNA modifications by quantitative RAPD-PCR across all exposure treatments. After 24 hours of recovery following a 2-hour exposure, probe hybridisation sites remained significantly decreased (~two-fold vs controls), and several stress/defence genes and proteins (including HSP70) were up-regulated, indicating a persistent stress response and genotoxic effect under the study conditions.",
    "effect_direction": "harm",
    "limitations": [
        "Sample size not reported in abstract",
        "Exposure described in V/m; dosimetry details beyond reported SAR range not provided in abstract",
        "Outcomes are molecular/biomarker endpoints in earthworms; relevance to human health not addressed in abstract"
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "900 MHz",
        "radiofrequency",
        "mobile phone frequency",
        "earthworm",
        "Eisenia fetida",
        "genotoxicity",
        "DNA modifications",
        "RAPD-PCR",
        "stress response",
        "HSP70",
        "oxidative stress",
        "CAT",
        "immune defence",
        "Western blot",
        "SAR"
    ],
    "suggested_hubs": [
        {
            "slug": "rf-genotoxicity",
            "weight": 0.7800000000000000266453525910037569701671600341796875,
            "reason": "Reports significant DNA modifications/genotoxic effects after 900 MHz RF exposure in an animal model."
        }
    ]
}

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