Effects of pulsing electromagnetic fields on the prenatal and postnatal development in mice and rats: in vivo and in vitro studies.

Abstract

Electromagnetic fields (EMF) might have various biological effects on the developing embryo. We studied the effects of pulsing electromagnetic fields (PEMF) on the in vitro development of preimplantation mouse embryos and of early somite rat embryos as well as on the in vivo development of rat embryos. We used PEMF at frequencies of 1, 20, 50, 70, and 100 Hz with a tension of 0.6 V/m. The embryos were exposed to PEMF throughout the experimental period. PEMF at frequencies of 20 and 50 Hz were embryotoxic, inhibiting over 50% of blastocysts from hatching and further development, all within 72 h of culture. PEMF at frequencies of 50 and 70 Hz induced 22% and 30% incidence of malformations in 10.5 day old rat embryos after 48 h in culture. The main malformations were absence of telencephalic, optic, and otic vesicles and of forelimb buds. In addition, retarded growth and development manifested by fewer somites, reduction in crown-rump length, and retarded closure of the neural tube were found in many embryos. No significant pathological changes were found by TEM in PEMF-exposed embryos. Disappearance of microvilli and collapse of apical parts of endodermal cells were observed by SEM in many yolk sacs of embryos exposed to 50 and 70 Hz PEMF. A slightly reduced litter average, a reduction or increase of weight, and a delay in eye opening was observed among offspring of pregnant rats exposed throughout pregnancy to PEMF at frequencies of 20, 50, and 100 Hz. No malformations were observed among these offspring. The mechanism of PEMF-induced embryotoxicity and teratogeneity is unknown, as is the mechanism of the "protective effects" of the mother on the rat embryos exposed to PEMF in vivo.

AI evidence extraction

Main findings

PEMF at 20 and 50 Hz inhibited >50% of mouse blastocyst hatching and further development within 72 h in culture. In rat embryo culture, 50 and 70 Hz PEMF were associated with malformations (22% and 30%) and growth/developmental delay; TEM showed no significant pathological changes, while SEM noted yolk sac surface changes at 50 and 70 Hz. In vivo exposure of pregnant rats (20, 50, 100 Hz) was associated with slightly reduced litter average, weight changes, and delayed eye opening in offspring, with no malformations observed.

Outcomes measured

• In vitro embryotoxicity (blastocyst hatching and development)
• In vitro malformations in rat embryos
• Growth/developmental delay markers (somite number, crown-rump length, neural tube closure)
• Ultrastructural changes (TEM/SEM findings)
• In vivo offspring outcomes (litter average, weight changes, eye opening delay, malformations)

Limitations

• Sample size not reported in abstract
• Exposure characterization limited to frequencies and electric field strength (0.6 V/m); other dosimetry details not provided
• Mechanism described as unknown in abstract

{
    "study_type": "animal",
    "exposure": {
        "band": "ELF",
        "source": null,
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": "Embryos exposed throughout the experimental period; in vitro: 72 h (mouse preimplantation) and 48 h (10.5-day rat embryos in culture); in vivo: pregnant rats exposed throughout pregnancy"
    },
    "population": "Mouse preimplantation embryos; rat embryos (early somite; 10.5-day embryos in culture); pregnant rats and offspring",
    "sample_size": null,
    "outcomes": [
        "In vitro embryotoxicity (blastocyst hatching and development)",
        "In vitro malformations in rat embryos",
        "Growth/developmental delay markers (somite number, crown-rump length, neural tube closure)",
        "Ultrastructural changes (TEM/SEM findings)",
        "In vivo offspring outcomes (litter average, weight changes, eye opening delay, malformations)"
    ],
    "main_findings": "PEMF at 20 and 50 Hz inhibited >50% of mouse blastocyst hatching and further development within 72 h in culture. In rat embryo culture, 50 and 70 Hz PEMF were associated with malformations (22% and 30%) and growth/developmental delay; TEM showed no significant pathological changes, while SEM noted yolk sac surface changes at 50 and 70 Hz. In vivo exposure of pregnant rats (20, 50, 100 Hz) was associated with slightly reduced litter average, weight changes, and delayed eye opening in offspring, with no malformations observed.",
    "effect_direction": "mixed",
    "limitations": [
        "Sample size not reported in abstract",
        "Exposure characterization limited to frequencies and electric field strength (0.6 V/m); other dosimetry details not provided",
        "Mechanism described as unknown in abstract"
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "pulsing electromagnetic fields",
        "PEMF",
        "ELF",
        "mouse embryos",
        "rat embryos",
        "prenatal development",
        "postnatal development",
        "embryotoxicity",
        "teratogenicity",
        "malformations",
        "TEM",
        "SEM"
    ],
    "suggested_hubs": []
}

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