Effects of extremely low-frequency electromagnetic field exposure on the skeletal muscle functions in rats.

Abstract

The aim of the present study was to systematically investigate the effects of chronic exposure to extremely low-frequency electromagnetic field (ELF-EMF) on electrophysiological, histological and biochemical properties of the diaphragm muscle in rats. Twenty-nine newly weaned (24 days old, 23-80 g) female ( = 15) and male ( = 14) Wistar Albino rats were used in this study. The animals were randomly divided into two groups: the control group and the electromagnetic field (EMF) group. The control group was also randomly divided into two groups: the control female group and the control male group. The EMF exposure group was also randomly divided into two groups: the ELF-EMF female group and the ELF-EMF male group. The rats in the ELF-EMF groups were exposed for 4 h daily for up to 7 months to 50 Hz frequency, 1.5 mT magnetic flux density. Under these experimental conditions, electrophysiological parameters (muscle bioelectrical activity parameters: intracellular action potential and resting membrane potential and muscle mechanical activity parameter: force-frequency relationship), biochemical parameters (Na, K, Cl and Ca levels in the blood serum of rats; Na-K ATP enzyme-specific activities in muscle tissue; and free radical metabolism in both muscle tissue and serum) and transmission electron microscopic morphometric parameters of the diaphragm muscle were determined. We found that chronic exposure to ELF-EMF had no significant effect on the histological structure and mechanical activity of the muscle and on the majority of muscle bioelectrical activity parameters, with the exception of some parameters of muscle bioelectrical activity. However, the changes in some bioelectrical activity parameters were relatively small and unlikely to be clinically relevant.

AI evidence extraction

Main findings

Rats exposed to 50 Hz, 1.5 mT ELF-EMF for 4 h/day up to 7 months showed no significant effects on diaphragm muscle histological structure or mechanical activity, and no significant effects on most muscle bioelectrical activity parameters. Some bioelectrical activity parameters changed, but changes were described as relatively small and unlikely to be clinically relevant.

Outcomes measured

• Diaphragm muscle electrophysiological parameters (intracellular action potential, resting membrane potential, force-frequency relationship)
• Histological structure of diaphragm muscle (transmission electron microscopy morphometrics)
• Biochemical parameters (serum Na, K, Cl, Ca; muscle Na-K ATPase activity; free radical metabolism in muscle tissue and serum)

Limitations

• Exposure source/setup not described in the abstract
• Statistical details and effect sizes for the altered bioelectrical parameters are not provided in the abstract
• Only diaphragm muscle assessed; generalizability to other muscles or outcomes is unclear from the abstract

Suggested hubs

• occupational-exposure (0.25)
  ELF (50 Hz) magnetic-field exposure is relevant to occupational/industrial EMF contexts, though this is an animal study and no workplace setting is specified.

{
    "study_type": "animal",
    "exposure": {
        "band": "ELF",
        "source": null,
        "frequency_mhz": 0.05000000000000000277555756156289135105907917022705078125,
        "sar_wkg": null,
        "duration": "4 h daily for up to 7 months"
    },
    "population": "Newly weaned (24 days old) female and male Wistar Albino rats",
    "sample_size": 29,
    "outcomes": [
        "Diaphragm muscle electrophysiological parameters (intracellular action potential, resting membrane potential, force-frequency relationship)",
        "Histological structure of diaphragm muscle (transmission electron microscopy morphometrics)",
        "Biochemical parameters (serum Na, K, Cl, Ca; muscle Na-K ATPase activity; free radical metabolism in muscle tissue and serum)"
    ],
    "main_findings": "Rats exposed to 50 Hz, 1.5 mT ELF-EMF for 4 h/day up to 7 months showed no significant effects on diaphragm muscle histological structure or mechanical activity, and no significant effects on most muscle bioelectrical activity parameters. Some bioelectrical activity parameters changed, but changes were described as relatively small and unlikely to be clinically relevant.",
    "effect_direction": "mixed",
    "limitations": [
        "Exposure source/setup not described in the abstract",
        "Statistical details and effect sizes for the altered bioelectrical parameters are not provided in the abstract",
        "Only diaphragm muscle assessed; generalizability to other muscles or outcomes is unclear from the abstract"
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "ELF-EMF",
        "extremely low-frequency",
        "50 Hz",
        "1.5 mT",
        "rats",
        "diaphragm muscle",
        "electrophysiology",
        "histology",
        "biochemistry",
        "Na-K ATPase",
        "free radicals"
    ],
    "suggested_hubs": [
        {
            "slug": "occupational-exposure",
            "weight": 0.25,
            "reason": "ELF (50 Hz) magnetic-field exposure is relevant to occupational/industrial EMF contexts, though this is an animal study and no workplace setting is specified."
        }
    ]
}

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