Cardiovascular, hematologic, and biochemical effects of acute ventral exposure of conscious rats to 2450-MHz (CW) microwave radiation.

Abstract

In this study the influence of acute (6 hr) exposure to 2450 MHz (CW) microwave radiation on certain cardiovascular, biochemical, and hematologic indices was examined in unanesthetized rats. Under methoxyflurane anesthesia, a catheter was inserted into the right femoral artery, which was used for monitoring blood pressure, heart rate, and blood sampling. Colonic temperature was monitored via a VITEK thermistor probe inserted rectally to a depth of 5 cm. The rat was subsequently placed into a ventilated restraining cage which was located inside an anechoic chamber. The temperature and humidity in the chamber were maintained at 22 +/- 0.5 degrees C and 60 +/- 5% (means +/- S.E.), respectively, during the experimental period. Rats (60) were exposed to either 0 (sham) or 10 mW/cm2 (exposed) for 6 hr. During exposure rats were oriented perpendicular to the E-field, and the measured specific absorption rate (SAR) was 3.7 mW/g. In the sham and exposed rats, the preexposure (time 0) mean +/- S.E. arterial blood pressure (MABP), heart rate, and colonic temperature were approximately 120 +/- 5 mmHg, 450 +/- 10 beats/min, and 37.0 +/- 0.2 degrees C, respectively. In the sham-exposed rats these values remained stable throughout the 6-hr exposure period. In the exposed rats, no effects were noted on MABP or colonic temperature; however after 1 hr of exposure, a significant reduction in heart rate was noted (450 versus 400 beats/min). This decrease in heart rate persisted throughout the remainder of the exposure period. None of the hematologic or biochemical parameters examined were affected by the microwave exposure. Although other mechanisms may be responsible, this decrease in heart rate may have been due to subtle cardiovascular adjustments because of microwave-induced heating with a resultant reduction in resting metabolic rate.

AI evidence extraction

Main findings

Rats exposed to 2450 MHz continuous-wave microwave radiation at 10 mW/cm2 for 6 hours (measured SAR 3.7 mW/g) showed no effects on mean arterial blood pressure or colonic temperature. Heart rate was significantly reduced after 1 hour of exposure (about 450 vs 400 beats/min) and remained reduced for the rest of the exposure period. No hematologic or biochemical parameters examined were affected.

Outcomes measured

• mean arterial blood pressure (MABP)
• heart rate
• colonic temperature
• hematologic parameters (unspecified)
• biochemical parameters (unspecified)

Limitations

• Specific hematologic and biochemical parameters are not listed in the abstract.
• Exposure described as ventral and orientation perpendicular to the E-field; generalizability to other exposure geometries is unclear from the abstract.
• Only acute (6-hour) exposure assessed; no longer-term outcomes reported.

{
    "study_type": "animal",
    "exposure": {
        "band": "microwave",
        "source": null,
        "frequency_mhz": 2450,
        "sar_wkg": 3.70000000000000017763568394002504646778106689453125,
        "duration": "6 hr (acute)"
    },
    "population": "Unanesthetized (conscious) rats",
    "sample_size": 60,
    "outcomes": [
        "mean arterial blood pressure (MABP)",
        "heart rate",
        "colonic temperature",
        "hematologic parameters (unspecified)",
        "biochemical parameters (unspecified)"
    ],
    "main_findings": "Rats exposed to 2450 MHz continuous-wave microwave radiation at 10 mW/cm2 for 6 hours (measured SAR 3.7 mW/g) showed no effects on mean arterial blood pressure or colonic temperature. Heart rate was significantly reduced after 1 hour of exposure (about 450 vs 400 beats/min) and remained reduced for the rest of the exposure period. No hematologic or biochemical parameters examined were affected.",
    "effect_direction": "mixed",
    "limitations": [
        "Specific hematologic and biochemical parameters are not listed in the abstract.",
        "Exposure described as ventral and orientation perpendicular to the E-field; generalizability to other exposure geometries is unclear from the abstract.",
        "Only acute (6-hour) exposure assessed; no longer-term outcomes reported."
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "2450 MHz",
        "continuous wave",
        "microwave radiation",
        "rats",
        "heart rate",
        "blood pressure",
        "colonic temperature",
        "SAR",
        "10 mW/cm2",
        "acute exposure"
    ],
    "suggested_hubs": []
}

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