Effects of pulse-modulated radiofrequency magnetic field (RF-EMF) exposure on apoptosis, autophagy, oxidative stress and electron chain transport function in human neuroblastoma and murine microglial cells

Abstract

Effects of pulse-modulated radiofrequency magnetic field (RF-EMF) exposure on apoptosis, autophagy, oxidative stress and electron chain transport function in human neuroblastoma and murine microglial cells Jana Zielinski, Angélique D. Ducray, Anja M. Moeller, Manuel Murbach, Niels Kuster, Meike Mevissen. Effects of pulse-modulated radiofrequency magnetic field (RF-EMF) exposure on apoptosis, autophagy, oxidative stress and electron chain transport function in human neuroblastoma and murine microglial cells. Toxicology in Vitro. Vol. 68, October 2020, 104963. doi.org. Highlights • RF-EMF exposure (935 MHz, 4 W/kg) did not cause apoptosis in SH-SY5Y and microglial cells. • The time-dependent increase in autophagy markers is related to the cell type. • A transient increase in oxidative stress was seen at SAR levels above the standards. Abstract The use of body-worn wireless devices with different communication protocols and rapidly changing exposure scenarios is still multiplying and the need to identify possible health effects of radiofrequency electromagnetic field (RF-EMF) exposure with extremely low-frequency (ELF) modulation envelops. In this study, effects of ELF- modulated 935 MHz RF-EMF on apoptosis, autophagy, oxidative stress and electron exchange in N9 microglial and SH-SY5Y neuroblastoma cells were investigated. Cells were exposed at 4 W/kg or sham-exposed for 2 and 24 h. RF-EMF exposure of both cell types did not alter apoptosis, the number of living cells nor the apoptosis-inducing factor (AIF), irrespective of the exposure duration. RF-EMF exposure for 24, but not for 2 h, increased protein levels of the autophagy marker ATG5, whereas LC3B-I and II and pERK were not altered in both cell types and exposure times investigated. A transient increase in glutathione (GSH), but not hydrogen peroxide and cytochrome c oxidase was found only in SH-SY5Y cells, indicating that short-time RF-EMF at SAR levels accepted by today's safety guidelines might cause autophagy and oxidative stress with the effect being dependent on cell type and exposure duration. Further studies are needed to evaluate possible underlying mechanisms involved in pulse-modulated RF-EMF exposure. sciencedirect.com

AI evidence extraction

Main findings

Cells exposed to ELF-modulated 935 MHz RF-EMF at 4 W/kg for 2 or 24 h showed no changes in apoptosis, number of living cells, or AIF in either cell type. After 24 h (but not 2 h), ATG5 protein levels increased, while LC3B-I/II and pERK were not altered. A transient increase in glutathione was observed only in SH-SY5Y cells; hydrogen peroxide and cytochrome c oxidase were not changed.

Outcomes measured

• Apoptosis
• Autophagy markers (ATG5, LC3B-I/II)
• Oxidative stress markers (glutathione, hydrogen peroxide)
• Electron chain transport / cytochrome c oxidase
• pERK
• Cell viability / number of living cells
• Apoptosis-inducing factor (AIF)

Limitations

• In vitro cell models (SH-SY5Y and N9) may not generalize to in vivo outcomes
• Only one RF frequency (935 MHz) and one SAR level (4 W/kg) reported
• Limited exposure durations (2 h and 24 h)
• Mechanisms not established; authors note further studies are needed
• Sample size and replication details not provided in abstract

Suggested hubs

• who-icnirp (0.32)
  Study explicitly references SAR levels accepted by current safety guidelines.

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    "study_type": "in_vitro",
    "exposure": {
        "band": "RF",
        "source": "body-worn wireless devices (context)",
        "frequency_mhz": 935,
        "sar_wkg": 4,
        "duration": "2 h and 24 h"
    },
    "population": "Human SH-SY5Y neuroblastoma cells and murine N9 microglial cells",
    "sample_size": null,
    "outcomes": [
        "Apoptosis",
        "Autophagy markers (ATG5, LC3B-I/II)",
        "Oxidative stress markers (glutathione, hydrogen peroxide)",
        "Electron chain transport / cytochrome c oxidase",
        "pERK",
        "Cell viability / number of living cells",
        "Apoptosis-inducing factor (AIF)"
    ],
    "main_findings": "Cells exposed to ELF-modulated 935 MHz RF-EMF at 4 W/kg for 2 or 24 h showed no changes in apoptosis, number of living cells, or AIF in either cell type. After 24 h (but not 2 h), ATG5 protein levels increased, while LC3B-I/II and pERK were not altered. A transient increase in glutathione was observed only in SH-SY5Y cells; hydrogen peroxide and cytochrome c oxidase were not changed.",
    "effect_direction": "mixed",
    "limitations": [
        "In vitro cell models (SH-SY5Y and N9) may not generalize to in vivo outcomes",
        "Only one RF frequency (935 MHz) and one SAR level (4 W/kg) reported",
        "Limited exposure durations (2 h and 24 h)",
        "Mechanisms not established; authors note further studies are needed",
        "Sample size and replication details not provided in abstract"
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "RF-EMF",
        "pulse-modulated",
        "ELF modulation",
        "935 MHz",
        "SAR 4 W/kg",
        "SH-SY5Y",
        "N9 microglia",
        "apoptosis",
        "autophagy",
        "ATG5",
        "oxidative stress",
        "glutathione",
        "cytochrome c oxidase"
    ],
    "suggested_hubs": [
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            "reason": "Study explicitly references SAR levels accepted by current safety guidelines."
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}

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