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

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.

AI evidence extraction

Main findings

In N9 microglial and SH-SY5Y neuroblastoma cells, ELF-modulated 935 MHz RF-EMF exposure at 4 W/kg for 2 or 24 h did not alter apoptosis, number of living cells, or AIF. 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 (GSH), but not hydrogen peroxide or cytochrome c oxidase, was observed only in SH-SY5Y cells.

Outcomes measured

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

Limitations

• In vitro cell models (N9 microglial and SH-SY5Y neuroblastoma) may not generalize to in vivo outcomes
• Sample size not reported in abstract
• Only two exposure durations (2 and 24 h) assessed
• Only one SAR level (4 W/kg) reported
• Some effects were cell-type and duration dependent

{
    "study_type": "in_vitro",
    "exposure": {
        "band": "RF",
        "source": "body-worn wireless devices",
        "frequency_mhz": 935,
        "sar_wkg": 4,
        "duration": "2 and 24 h"
    },
    "population": null,
    "sample_size": null,
    "outcomes": [
        "Apoptosis",
        "Autophagy (ATG5, LC3B-I/II)",
        "Oxidative stress (GSH, hydrogen peroxide)",
        "Electron chain transport function (cytochrome c oxidase)",
        "Cell viability/number of living cells",
        "AIF (apoptosis-inducing factor)",
        "pERK"
    ],
    "main_findings": "In N9 microglial and SH-SY5Y neuroblastoma cells, ELF-modulated 935 MHz RF-EMF exposure at 4 W/kg for 2 or 24 h did not alter apoptosis, number of living cells, or AIF. 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 (GSH), but not hydrogen peroxide or cytochrome c oxidase, was observed only in SH-SY5Y cells.",
    "effect_direction": "mixed",
    "limitations": [
        "In vitro cell models (N9 microglial and SH-SY5Y neuroblastoma) may not generalize to in vivo outcomes",
        "Sample size not reported in abstract",
        "Only two exposure durations (2 and 24 h) assessed",
        "Only one SAR level (4 W/kg) reported",
        "Some effects were cell-type and duration dependent"
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "RF-EMF",
        "ELF modulation",
        "pulse-modulated",
        "935 MHz",
        "SAR 4 W/kg",
        "SH-SY5Y",
        "N9 microglia",
        "apoptosis",
        "autophagy",
        "ATG5",
        "oxidative stress",
        "glutathione",
        "electron transport chain",
        "cytochrome c oxidase"
    ],
    "suggested_hubs": []
}

Comments

Log in to comment.

No comments yet.