Teratogenic effects of sinusoidal extremely low frequency electromagnetic fields on morphology of 24 hr chick embryos.

Abstract

To examine the potential teratogenicity of electromagnetic fields (EMF; sinusoidal and rectangular) on development of chick embryos (white leghorn), 221 freshly fertilized chicken eggs (55-65 g) were exposed during first 24 hr of postlaying incubation (38 degrees +/- 0.5 degree C) to 24 different EMFs, with 50Hz repetition rate and 8.007-10.143 mT flux density. Following exposure, the exposed fertilized chicken eggs (n = 8-10) and sham-exposed fertilized chicken eggs (n = 15) were incubated simultaneously for 8 more days and unexposed control fertilized chicken eggs (n = 20) for 9 days in absence of EMFs. The embryos were removed from egg shells and studied blind. All 24 EMF exposed-groups (inside the coil with exposure) showed an increase in the percentage of developmental anomalies compared to sham-exposed (inside the coil with no exposure) and control groups (outside the coil). Further, egg's weight was evaluated on day 9. This variable did not show significant difference between control and exposed-groups. The investigation also covered the measurement of body weight, length of crown to rump, length of tip of the beak to occipital bone, heart and liver weight. Statistical comparison between sham-exposed and control values did not show significant differences, but comparison between 8.007, 8.453 and 8.713 mT exposed-groups and control groups showed significant differences; in other exposed-groups, the changes were not significant. These results revealed that 50 Hz electromagnetic fields can induce irreversible developmental alterations in 24 hr chick embryos and confirm that its strength could be a determinant factor for the embryonic response to extremely low frequency electromagnetic fields (window effects).

AI evidence extraction

Main findings

Across 24 exposed groups (50 Hz; 8.007–10.143 mT), the percentage of developmental anomalies was increased compared with sham-exposed and unexposed controls. Egg weight on day 9 did not differ significantly between control and exposed groups. Some exposure groups (8.007, 8.453, 8.713 mT) showed significant differences vs controls in measured morphometric/organ-weight variables, while other exposed groups did not show significant changes.

Outcomes measured

• Developmental anomalies (percentage)
• Egg weight (day 9)
• Embryo body weight
• Crown–rump length
• Beak tip to occipital bone length
• Heart weight
• Liver weight

Limitations

• Animal model (chick embryos); relevance to humans not addressed in abstract
• Exposure described as 24 different EMFs (sinusoidal and rectangular) but results are not clearly separated by waveform in the abstract
• Small per-group sample sizes for exposed groups (n=8–10) and sham (n=15)
• Multiple exposure groups and multiple outcomes; approach to multiple comparisons not described in abstract

Suggested hubs

• animal-studies (0.9)
  Experimental exposure study in chick embryos assessing developmental outcomes under ELF EMF.

{
    "study_type": "animal",
    "exposure": {
        "band": "ELF",
        "source": null,
        "frequency_mhz": 0.05000000000000000277555756156289135105907917022705078125,
        "sar_wkg": null,
        "duration": "first 24 hr of postlaying incubation (exposure during first 24 hr); then incubated 8–9 more days without EMFs"
    },
    "population": "White leghorn chick embryos (fertilized chicken eggs)",
    "sample_size": 221,
    "outcomes": [
        "Developmental anomalies (percentage)",
        "Egg weight (day 9)",
        "Embryo body weight",
        "Crown–rump length",
        "Beak tip to occipital bone length",
        "Heart weight",
        "Liver weight"
    ],
    "main_findings": "Across 24 exposed groups (50 Hz; 8.007–10.143 mT), the percentage of developmental anomalies was increased compared with sham-exposed and unexposed controls. Egg weight on day 9 did not differ significantly between control and exposed groups. Some exposure groups (8.007, 8.453, 8.713 mT) showed significant differences vs controls in measured morphometric/organ-weight variables, while other exposed groups did not show significant changes.",
    "effect_direction": "harm",
    "limitations": [
        "Animal model (chick embryos); relevance to humans not addressed in abstract",
        "Exposure described as 24 different EMFs (sinusoidal and rectangular) but results are not clearly separated by waveform in the abstract",
        "Small per-group sample sizes for exposed groups (n=8–10) and sham (n=15)",
        "Multiple exposure groups and multiple outcomes; approach to multiple comparisons not described in abstract"
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "extremely low frequency",
        "ELF",
        "50 Hz",
        "magnetic flux density",
        "mT",
        "chick embryo",
        "teratogenicity",
        "developmental anomalies",
        "morphology",
        "window effects"
    ],
    "suggested_hubs": [
        {
            "slug": "animal-studies",
            "weight": 0.90000000000000002220446049250313080847263336181640625,
            "reason": "Experimental exposure study in chick embryos assessing developmental outcomes under ELF EMF."
        }
    ]
}

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