The guardians of germ cells; Sertoli-derived exosomes against electromagnetic field-induced oxidative stress in mouse spermatogonial stem cells.

Abstract

Nowadays, prolonged exposure to electromagnetic fields (EMF) has raised public concern about the detrimental potential of EMF on spermatogonial stem cells (SSCs) and spermatogenesis. Recent studies introduced the fundamental role of Sertoli cell paracrine signaling in the regulation of SSCs maintenance and differentiation in fertility preservation. Thus we investigated the therapeutic effect of Sertoli-derived exosomes (Sertoli-EXOs) as powerful paracrine mediators in SSCs subjected to EMF and its underlying mechanisms. SSCs and Sertoli cells were isolated from neonate mice testis, and identified by their specific markers. Then SSCs were exposed to 50 Hz EMF with intensity of 2.5 mT (1 h for 5 days) and supplemented with exosomes that were isolated from pre-pubertal Sertoli cells. Sertoli-EXOs were characterized and the uptake was observed by PKH26 labeling. The cell viability, colonization efficiency, reactive oxygen species (ROS) balance, cell cycle arrest and apoptosis induction were then analysed. SSCs were confirmed by immunocytochemistry (Oct4, Plzf) and Sertoli cells were identified through Sox9 and vimentin expression by immunocytochemistry and Real-time PCR (qRT-PCR), respectively. Our results demonstrated the detrimental effect of EMF via ROS accumulation that reduced the expression of catalase antioxidant, cell viability and colonization of SSCs. Also, AO/PI and flow cytometry analysis demonstrated the elevation of apoptosis in SSCs exposed to EMF in comparison with control. qRT-PCR data confirmed the up-regulation of apoptotic gene (Caspase-3) and down-regulation of SSCs specific gene (GFRα1). Consequently, the administration of Sertoli-EXOs exerted ameliorative effect on SSCs and significantly improved these changes through the regulation of oxidative stress. These findings suggest that Sertoli-EXOs have positive impact on SSCs exposed to EMF and can be useful in further investigation of Sertoli-EXOs as a novel therapeutic agent which may recover the deregulated SSCs microenvironment and spermatogenesis after exposure to EMF.

AI evidence extraction

Main findings

Exposure of SSCs to 50 Hz EMF (2.5 mT; 1 h for 5 days) increased ROS accumulation, reduced catalase expression, and decreased SSC viability and colonization. EMF exposure increased apoptosis (AO/PI and flow cytometry), with qRT-PCR showing up-regulation of Caspase-3 and down-regulation of GFRα1; supplementation with Sertoli-derived exosomes ameliorated these changes via regulation of oxidative stress.

Outcomes measured

• Cell viability
• Colonization efficiency
• Reactive oxygen species (ROS) balance/oxidative stress
• Catalase antioxidant expression
• Cell cycle arrest
• Apoptosis (AO/PI, flow cytometry)
• Gene expression: Caspase-3
• Gene expression: GFRα1

Limitations

• In vitro study (mouse SSCs/Sertoli cells)
• Sample size not reported in abstract
• Exposure conditions limited to 50 Hz, 2.5 mT, 1 h for 5 days
• Mechanistic and outcome measures limited to cellular/biomarker endpoints; no in vivo fertility outcomes reported

Suggested hubs

• elf-emf (0.9)
  Study uses 50 Hz extremely low frequency EMF exposure.
• male-fertility (0.75)
  Focuses on spermatogonial stem cells and spermatogenesis-related endpoints.

{
    "study_type": "in_vitro",
    "exposure": {
        "band": "ELF",
        "source": "laboratory EMF exposure",
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": "50 Hz, 2.5 mT, 1 h/day for 5 days"
    },
    "population": "Mouse spermatogonial stem cells (SSCs) isolated from neonate mice testis; Sertoli cells from pre-pubertal mice (for exosome isolation)",
    "sample_size": null,
    "outcomes": [
        "Cell viability",
        "Colonization efficiency",
        "Reactive oxygen species (ROS) balance/oxidative stress",
        "Catalase antioxidant expression",
        "Cell cycle arrest",
        "Apoptosis (AO/PI, flow cytometry)",
        "Gene expression: Caspase-3",
        "Gene expression: GFRα1"
    ],
    "main_findings": "Exposure of SSCs to 50 Hz EMF (2.5 mT; 1 h for 5 days) increased ROS accumulation, reduced catalase expression, and decreased SSC viability and colonization. EMF exposure increased apoptosis (AO/PI and flow cytometry), with qRT-PCR showing up-regulation of Caspase-3 and down-regulation of GFRα1; supplementation with Sertoli-derived exosomes ameliorated these changes via regulation of oxidative stress.",
    "effect_direction": "mixed",
    "limitations": [
        "In vitro study (mouse SSCs/Sertoli cells)",
        "Sample size not reported in abstract",
        "Exposure conditions limited to 50 Hz, 2.5 mT, 1 h for 5 days",
        "Mechanistic and outcome measures limited to cellular/biomarker endpoints; no in vivo fertility outcomes reported"
    ],
    "evidence_strength": "low",
    "confidence": 0.85999999999999998667732370449812151491641998291015625,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "electromagnetic fields",
        "ELF-EMF",
        "50 Hz",
        "2.5 mT",
        "spermatogonial stem cells",
        "Sertoli cells",
        "exosomes",
        "oxidative stress",
        "ROS",
        "apoptosis",
        "catalase",
        "Caspase-3",
        "GFRα1"
    ],
    "suggested_hubs": [
        {
            "slug": "elf-emf",
            "weight": 0.90000000000000002220446049250313080847263336181640625,
            "reason": "Study uses 50 Hz extremely low frequency EMF exposure."
        },
        {
            "slug": "male-fertility",
            "weight": 0.75,
            "reason": "Focuses on spermatogonial stem cells and spermatogenesis-related endpoints."
        }
    ]
}

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