Light and electron microscope studies of effects of 50 Hz electromagnetic fields on preincubated chick embryo.

Abstract

We investigated the effects of an electromagnetic field (EMF) of 50 Hz, 1.33-7.32 mT on sections of preincubated white leghorn chicken embryos using light, SEM and TEM microscopes. Five hundred healthy, fresh, and fertilized eggs (55-65 g) were divided into three groups of experimental (n = 18-20), control (n = 60), and sham (n = 50). Experimental eggs (inside the coil) were exposed to 15 different intensities (1.33-7.32 mT) for morphological surveys and to the known most effective intensities for light, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) studies. Sham groups were located inside the same coil with no exposure for 24 h before incubation. Control, sham, and experimental groups were then incubated in an incubator (38 +/- 0.5 degrees C, 60% humidity) for 4 days. At the end of this period, embryos were removed from their shells, prepared for morphometric, light, and SEM/TEM studies. Results of light microscopic studies (serial sections, 6mu) and morphometric data showed significant differences between different groups (P < 0.005). Larger and abnormal brain cavities, spina bifida, monophthalmia, microphthalmia, anophthalmia, and growth retardation were shown on SEM. TEM sections demonstrated that the nucleus was condensed, the nuclear envelope disappeared, and mitochondria degenerated. Golgi apparatus and endoplasmic reticulum were the least affected organelles. The Telencephlon was the most affected region, and the retina was altered more than the lens. We conclude that EMFs affect the brain, especially the Telencephalon and eye of preincubated-exposed chick embryo at the morphological and cellular level, nuclei are the most affected part, and our data agrees with "Ubeda's windows effects" of EMFs on preincubated chick embryos.

AI evidence extraction

Main findings

Exposure to 50 Hz EMF at 1.33–7.32 mT was associated with significant differences between groups (P < 0.005) in light microscopy/morphometric measures. SEM reported abnormalities including larger/abnormal brain cavities, spina bifida, and eye malformations, and TEM showed nuclear condensation, disappearance of the nuclear envelope, and mitochondrial degeneration; telencephalon and retina were described as most affected.

Outcomes measured

• Morphological abnormalities (e.g., brain cavity changes, spina bifida, eye malformations)
• Growth retardation
• Histological/morphometric differences on light microscopy
• Ultrastructural cellular changes on TEM (nuclear condensation, loss of nuclear envelope, mitochondrial degeneration)

Limitations

• Exposure duration for the experimental group is not clearly stated in the abstract (only sham group timing is specified).
• Group sizes for the experimental condition are unclear/inconsistent (experimental described as n=18–20 despite 15 intensities).
• Outcome assessment appears largely morphological/qualitative; blinding and randomization are not described in the abstract.

Suggested hubs

• occupational-exposure (0.2)
  Study uses relatively high-intensity 50 Hz magnetic fields (mT range), which can overlap with occupational/industrial ELF exposure contexts, though no specific source is stated.

{
    "study_type": "animal",
    "exposure": {
        "band": "ELF",
        "source": null,
        "frequency_mhz": 0.05000000000000000277555756156289135105907917022705078125,
        "sar_wkg": null,
        "duration": "24 h before incubation (sham described as no exposure for 24 h; exposure duration not explicitly stated)"
    },
    "population": "Preincubated white leghorn chicken embryos (fertilized eggs)",
    "sample_size": 500,
    "outcomes": [
        "Morphological abnormalities (e.g., brain cavity changes, spina bifida, eye malformations)",
        "Growth retardation",
        "Histological/morphometric differences on light microscopy",
        "Ultrastructural cellular changes on TEM (nuclear condensation, loss of nuclear envelope, mitochondrial degeneration)"
    ],
    "main_findings": "Exposure to 50 Hz EMF at 1.33–7.32 mT was associated with significant differences between groups (P < 0.005) in light microscopy/morphometric measures. SEM reported abnormalities including larger/abnormal brain cavities, spina bifida, and eye malformations, and TEM showed nuclear condensation, disappearance of the nuclear envelope, and mitochondrial degeneration; telencephalon and retina were described as most affected.",
    "effect_direction": "harm",
    "limitations": [
        "Exposure duration for the experimental group is not clearly stated in the abstract (only sham group timing is specified).",
        "Group sizes for the experimental condition are unclear/inconsistent (experimental described as n=18–20 despite 15 intensities).",
        "Outcome assessment appears largely morphological/qualitative; blinding and randomization are not described in the abstract."
    ],
    "evidence_strength": "low",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "50 Hz",
        "ELF-EMF",
        "millitesla",
        "chick embryo",
        "preincubation exposure",
        "light microscopy",
        "SEM",
        "TEM",
        "morphology",
        "telencephalon",
        "retina",
        "spina bifida",
        "eye malformations"
    ],
    "suggested_hubs": [
        {
            "slug": "occupational-exposure",
            "weight": 0.200000000000000011102230246251565404236316680908203125,
            "reason": "Study uses relatively high-intensity 50 Hz magnetic fields (mT range), which can overlap with occupational/industrial ELF exposure contexts, though no specific source is stated."
        }
    ]
}

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