p25/CDK5 is partially involved in neuronal injury induced by radiofrequency electromagnetic field exposure.

Abstract

PURPOSE: Several studies suggest that radiofrequency electromagnetic field (RF-EMF) exposure can induce neuronal injury. The aim of the present work was to investigate whether the cyclin-dependent kinase 5 (CDK5) pathway is involved in neuronal injury induced by RF-EMF exposure. MATERIALS AND METHODS: Newborn Sprague-Dawley rats' primary cultured cortical neurons were exposed to pulsed 2.45 GHz RF-EMF for 10 min. The cellular viability was assessed using the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The apoptosis was assessed by Hoechst 33342 and terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling co-staining. The protein expressions of CDK5, p35, p25, and phosphorylated tau at Ser(404) were examined by Western blot analysis. The CDK5 activity was detected using a histone-H1 kinase assay. RESULTS: The cellular viability of neurons was significantly decreased (p < 0.01, Partial Eta Squared [ηp(2)]: 0.554), and the percentage of apoptotic nuclei (p < 0.01, ηp(2) = 0.689), activity of CDK5 (p < 0.05, ηp(2) = 0.589), ratio of p25 and p35 (p < 0.05, ηp(2 =) 0.670), levels of tau phosphorylation at Ser(404) (p < 0.01, ηp(2) = 0.896) were significantly increased after RF-EMF exposure. No significant change was detected in CDK5 expression after RF-EMF exposure. Pretreatment with Roscovitine (a CDK5 inhibitor) significantly blocked the RF-EMF-induced decrease of cellular viability (p < 0.05, ηp(2) = 0.398) and tau hyperphosphorylation at Ser(404) (p < 0.01, ηp(2 =) 0.917), but did not significantly block the RF-EMF-induced apoptosis (p > 0.05, ηp(2) = 0.130). CONCLUSIONS: These results suggest that abnormal activity of p25/CDK5 is partially involved in primary cultured cortical neuron injury induced by RF-EMF exposure.

AI evidence extraction

Main findings

After 10 min pulsed 2.45 GHz RF-EMF exposure, neuronal cell viability decreased and apoptotic nuclei increased; CDK5 activity, p25/p35 ratio, and tau phosphorylation at Ser(404) increased, while CDK5 expression did not change. Roscovitine pretreatment significantly blocked the RF-EMF-induced decrease in viability and tau hyperphosphorylation but did not significantly block RF-EMF-induced apoptosis.

Outcomes measured

• Cell viability (MTT assay)
• Apoptosis (Hoechst 33342 and TUNEL co-staining)
• Protein expression of CDK5, p35, p25, phosphorylated tau Ser(404) (Western blot)
• CDK5 activity (histone-H1 kinase assay)
• Effect of CDK5 inhibitor roscovitine on RF-EMF-induced changes

Limitations

• In vitro primary neuron culture model; may not generalize to in vivo or humans
• Exposure metric (e.g., SAR) not reported in abstract
• Sample size and replication details not reported in abstract
• Single frequency and short exposure duration (10 min)

{
    "study_type": "in_vitro",
    "exposure": {
        "band": "RF",
        "source": null,
        "frequency_mhz": 2450,
        "sar_wkg": null,
        "duration": "10 min (pulsed)"
    },
    "population": "Primary cultured cortical neurons from newborn Sprague-Dawley rats",
    "sample_size": null,
    "outcomes": [
        "Cell viability (MTT assay)",
        "Apoptosis (Hoechst 33342 and TUNEL co-staining)",
        "Protein expression of CDK5, p35, p25, phosphorylated tau Ser(404) (Western blot)",
        "CDK5 activity (histone-H1 kinase assay)",
        "Effect of CDK5 inhibitor roscovitine on RF-EMF-induced changes"
    ],
    "main_findings": "After 10 min pulsed 2.45 GHz RF-EMF exposure, neuronal cell viability decreased and apoptotic nuclei increased; CDK5 activity, p25/p35 ratio, and tau phosphorylation at Ser(404) increased, while CDK5 expression did not change. Roscovitine pretreatment significantly blocked the RF-EMF-induced decrease in viability and tau hyperphosphorylation but did not significantly block RF-EMF-induced apoptosis.",
    "effect_direction": "harm",
    "limitations": [
        "In vitro primary neuron culture model; may not generalize to in vivo or humans",
        "Exposure metric (e.g., SAR) not reported in abstract",
        "Sample size and replication details not reported in abstract",
        "Single frequency and short exposure duration (10 min)"
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "radiofrequency electromagnetic field",
        "RF-EMF",
        "2.45 GHz",
        "pulsed exposure",
        "primary cortical neurons",
        "Sprague-Dawley rat",
        "neuronal injury",
        "apoptosis",
        "cell viability",
        "CDK5",
        "p25",
        "p35",
        "tau phosphorylation",
        "Ser404",
        "roscovitine"
    ],
    "suggested_hubs": []
}

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