Long-term, low-level microwave irradiation of rats.

PAPER pubmed Bioelectromagnetics 1992 Animal study Effect: unclear Evidence: Insufficient

Read original paper → DOI: 10.1002/bem.2250130605 PMID: 1482413 Evidence Lab

Abstract

Our goal was to investigate effects of long-term exposure to pulsed microwave radiation. The major emphasis was to expose a large sample of experimental animals throughout their lifetimes and to monitor them for effects on general health and longevity. An exposure facility was developed that enabled 200 rats to be maintained under specific-pathogen-free (SPF) conditions while housed individually in circularly-polarized waveguides. The exposure facility consisted of two rooms, each containing 50 active waveguides and 50 waveguides for sham (control) exposures. The experimental rats were exposed to 2,450-MHz pulsed microwaves at 800 pps with a 10-microseconds pulse width. The pulsed microwaves were square-wave modulated at 8-Hz. Whole body calorimetry, thermographic analysis, and power-meter analysis indicated that microwaves delivered at 0.144 W to each exposure waveguide resulted in an average specific absorption rate (SAR) that ranged from 0.4 W/kg for a 200-g rat to 0.15 W/kg for an 800-g rat. Two hundred male, Sprague-Dawley rats were assigned in equal numbers to radiation-exposure and sham-exposure conditions. Exposure began at 8 weeks of age and continued daily, 21.5 h/day, for 25 months. Animals were bled at regular intervals and blood samples were analyzed for serum chemistries, hematological values, protein electrophoretic patterns, thyroxine, and plasma corticosterone levels. In addition to daily measures of body mass, food and water consumption by all animals, O2 consumption and CO2 production were periodically measured in a sub-sample (N = 18) of each group. Activity was assessed in an open-field apparatus at regular intervals throughout the study. After 13 months, 10 rats from each group were euthanatized to test for immunological competence and to permit whole-body analysis, as well as gross and histopathological examinations. At the end of 25 months, the survivors (11 sham-exposed and 12 radiation-exposed rats) were euthanatized for similar analyses. The other 157 animals were examined histopathologically when they died spontaneously or were terminated in extremis.

AI evidence extraction

At a glance

Study type

Animal study

Effect direction

unclear

Population

Male Sprague-Dawley rats (SPF conditions)

Sample size

200

Exposure

microwave · 2450 MHz · Daily exposure 21.5 h/day for 25 months (began at 8 weeks of age); pulsed at 800 pps with 10 µs pulse width; square-wave modulated at 8 Hz

Evidence strength

Insufficient

Confidence: 74% · Peer-reviewed: yes

Outcomes measured

general health
longevity/survival
serum chemistries
hematological values
protein electrophoretic patterns
thyroxine
plasma corticosterone
body mass
food consumption
water consumption
O2 consumption
CO2 production
activity (open-field)
immunological competence
gross pathology
histopathology

Limitations

Abstract describes study design and measurements but does not report results or statistical comparisons.
Average SAR is reported as a range by body mass (0.4 to 0.15 W/kg) rather than a single value for the cohort.

View raw extracted JSON

{
    "study_type": "animal",
    "exposure": {
        "band": "microwave",
        "source": null,
        "frequency_mhz": 2450,
        "sar_wkg": null,
        "duration": "Daily exposure 21.5 h/day for 25 months (began at 8 weeks of age); pulsed at 800 pps with 10 µs pulse width; square-wave modulated at 8 Hz"
    },
    "population": "Male Sprague-Dawley rats (SPF conditions)",
    "sample_size": 200,
    "outcomes": [
        "general health",
        "longevity/survival",
        "serum chemistries",
        "hematological values",
        "protein electrophoretic patterns",
        "thyroxine",
        "plasma corticosterone",
        "body mass",
        "food consumption",
        "water consumption",
        "O2 consumption",
        "CO2 production",
        "activity (open-field)",
        "immunological competence",
        "gross pathology",
        "histopathology"
    ],
    "main_findings": null,
    "effect_direction": "unclear",
    "limitations": [
        "Abstract describes study design and measurements but does not report results or statistical comparisons.",
        "Average SAR is reported as a range by body mass (0.4 to 0.15 W/kg) rather than a single value for the cohort."
    ],
    "evidence_strength": "insufficient",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "rats",
        "Sprague-Dawley",
        "pulsed microwaves",
        "2450 MHz",
        "long-term exposure",
        "lifetime exposure",
        "SAR",
        "sham control",
        "longevity",
        "histopathology",
        "immunology"
    ],
    "suggested_hubs": []
}

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AI-extracted fields are generated from the abstract/metadata and may be incomplete or incorrect. This content is for informational purposes only and is not medical advice.

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