Deleterious impacts of a 900-MHz electromagnetic field on hippocampal pyramidal neurons of 8-week-old Sprague Dawley male rats.

Abstract

Children are at potential risk due to their intense use of mobile phones. We examined 8-week-old rats because this age of the rats is comparable with the preadolescent period in humans. The number of pyramidal neurons in the cornu ammonis of the Sprague Dawley male rat (8-weeks old, weighing 180-250 g) hippocampus following exposure to a 900 MHz (MHz) electromagnetic field (EMF) were examined. The study consisted of control (CN-G), sham exposed (SHM-EG) and EMF exposed (EMF-EG) groups with 6 rats in each. The EMF-EG rats were exposed to 900 MHz EMF (1h/day for 30 days) in an EMF jar. The SHM-EG rats were placed in the EMF jar but not exposed to the EMF (1h/day for 30 days). The CN-G rats were not placed into the exposure jar and were not exposed to the EMF during the study period. All animals were sacrificed at the end of the experiment, and their brains were removed for histopathological and stereological analysis. The number of pyramidal neurons in the cornu ammonis of the hippocampus was estimated on Cresyl violet stained sections of the brain using the optical dissector counting technique. Histopathological evaluations were also performed on these sections. Histopathological observation showed abundant cells with abnormal, black or dark blue cytoplasm and shrunken morphology among the normal pyramidal neurons. The largest lateral ventricles were observed in the EMF-EG sections compared to those from the other groups. Stereological analyses showed that the total number of pyramidal neurons in the cornu ammonis of the EMF-EG rats was significantly lower than those in the CN-G (p<0.05) and the SHM-EG (p<0.05). In conclusion, our results suggest that pyramidal neuron loss and histopathological changes in the cornu ammonis of 8-week-old male rats may be due to the 900-MHz EMF exposure.

AI evidence extraction

Main findings

Rats exposed to a 900 MHz EMF for 1 h/day for 30 days had a significantly lower total number of pyramidal neurons in the cornu ammonis than control and sham-exposed groups (p<0.05). Histopathology in the exposed group showed abnormal, dark-stained/shrunken cells among pyramidal neurons and larger lateral ventricles compared with other groups.

Outcomes measured

• Hippocampal (cornu ammonis) pyramidal neuron number (stereological estimate)
• Histopathological changes in hippocampal sections (abnormal cytoplasm, shrunken morphology)
• Lateral ventricle size (histopathological observation)

Limitations

• Small group sizes (6 rats per group)
• SAR/dosimetry not reported in abstract
• Exposure described as in an 'EMF jar'; field characterization not provided in abstract

Suggested hubs

• mobile-phones (0.85)
  Exposure is 900 MHz RF EMF framed in context of mobile phone use.

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    "study_type": "animal",
    "exposure": {
        "band": "RF",
        "source": "mobile phone",
        "frequency_mhz": 900,
        "sar_wkg": null,
        "duration": "1 h/day for 30 days"
    },
    "population": "8-week-old Sprague Dawley male rats (180–250 g)",
    "sample_size": 18,
    "outcomes": [
        "Hippocampal (cornu ammonis) pyramidal neuron number (stereological estimate)",
        "Histopathological changes in hippocampal sections (abnormal cytoplasm, shrunken morphology)",
        "Lateral ventricle size (histopathological observation)"
    ],
    "main_findings": "Rats exposed to a 900 MHz EMF for 1 h/day for 30 days had a significantly lower total number of pyramidal neurons in the cornu ammonis than control and sham-exposed groups (p<0.05). Histopathology in the exposed group showed abnormal, dark-stained/shrunken cells among pyramidal neurons and larger lateral ventricles compared with other groups.",
    "effect_direction": "harm",
    "limitations": [
        "Small group sizes (6 rats per group)",
        "SAR/dosimetry not reported in abstract",
        "Exposure described as in an 'EMF jar'; field characterization not provided in abstract"
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "900 MHz",
        "RF EMF",
        "hippocampus",
        "cornu ammonis",
        "pyramidal neurons",
        "Sprague Dawley",
        "rat",
        "histopathology",
        "stereology",
        "optical dissector",
        "Cresyl violet"
    ],
    "suggested_hubs": [
        {
            "slug": "mobile-phones",
            "weight": 0.84999999999999997779553950749686919152736663818359375,
            "reason": "Exposure is 900 MHz RF EMF framed in context of mobile phone use."
        }
    ]
}

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