Evaluation of oxidative injury in sciatic nerves of male rats exposed to continuous 900-MHz EMF throughout adolescence

Abstract

Evaluation of oxidative injury in sciatic nerves of male rats exposed to continuous 900-MHz EMF throughout adolescence Kerimoğlu G, Güney C, Ersöz Ş, Odacı E. A histopathological and biochemical evaluation of oxidative injury in the sciatic nerves of male rats exposed to a continuous 900-megahertz electromagnetic field throughout all periods of adolescence. J Chem Neuroanat. 2018 Jan 10. pii: S0891-0618(17)30212-0. doi: 10.1016/j.jchemneu.2018.01.001. Abstract The effects on human health of the electromagnetic field (EMF) emitted by mobile phones, used by approximately 7 billion people worldwide, have become an important subject for scientific research. Studies have suggested that the EMF emitted by mobile phones can cause oxidative stress in different tissues and age groups. Young people in adolescence, a time period when risky behaviors and dependences increase, use mobile phones more than adults. The EMF emitted by mobile phones, which are generally carried in the pocket or in bags when not in use, will very probably affect the sciatic nerve. No previous study has investigated the effect of mobile phone use in adolescence on peripheral nerve. This study was planned accordingly. Twenty-four male Sprague Dawley rats aged 21 days were divided equally into control (CGr), Sham (SGr) and EMF (EMFGr) groups. No procedure was performed on CGr rats. EMFGr were exposed to the effect of a 900-megahertz (MHz) EMF for 1 h at the same time every day between postnatal days 21-59 (the entire adolescent period) inside a cage in the EMF apparatus. SGr rats were placed inside the cage for 1 h every day without being exposed to EMF. All rats were sacrificed at the end of the study period, and 1 cm sections of sciatic nerve were extracted. Malondialdehyde (MDA), glutathione, catalase (CAT) superoxide dismutase (SOD) values were investigated biochemically in half of the right sciatic nerve tissues. The other halves of the nerve tissues were subjected to routine histopathological tissue procedures, sectioned and stained with hematoxylin and eosin (H&E) and Masson's trichrome. Histopathological evaluation of slides stained with Masson's trichrome and H&E revealed a normal appearance in Schwann cells and axons in all groups. However, there was marked thickening in the epineurium of sciatic nerves from EMFGr rats. MDA, SOD and CAT levels were higher in EMFGr than in CGr and SGr at biochemical analyses. Apoptotıc index (AI) analysis revealed a significant increase in the number of TUNEL (+) cells when EMFGr was compared with CGr and SGr. In conclusion, our study results suggest that continuous exposure to a 900-MHz EMF for 1 h throughout adolescence can cause oxidative injury and thickening in the epineurium in the sciatic nerve in male rats. ncbi.nlm.nih.gov

AI evidence extraction

Main findings

Histopathology showed normal Schwann cells and axons in all groups, but marked thickening of the epineurium in the EMF-exposed group. Biochemically, MDA, SOD, and CAT levels were higher in the EMF group than control and sham, and TUNEL(+) cells (apoptotic index) were significantly increased in the EMF group.

Outcomes measured

• Sciatic nerve histopathology (H&E, Masson's trichrome)
• Epineurium thickness
• Oxidative stress/antioxidant markers in sciatic nerve tissue (MDA, glutathione, CAT, SOD)
• Apoptosis (TUNEL-positive cells; apoptotic index)

Limitations

• Animal study (male rats); human relevance not directly assessed
• Exposure described as 900 MHz EMF in an apparatus; dosimetry/SAR not reported in abstract
• Sample size per group is small (n=8)

Suggested hubs

• animal-studies (0.9)
  Rat experiment assessing peripheral nerve outcomes after RF-EMF exposure.

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    "study_type": "animal",
    "exposure": {
        "band": "RF",
        "source": "mobile phone",
        "frequency_mhz": 900,
        "sar_wkg": null,
        "duration": "1 h/day, postnatal days 21–59 (entire adolescence period)"
    },
    "population": "Male Sprague Dawley rats (aged 21 days at start)",
    "sample_size": 24,
    "outcomes": [
        "Sciatic nerve histopathology (H&E, Masson's trichrome)",
        "Epineurium thickness",
        "Oxidative stress/antioxidant markers in sciatic nerve tissue (MDA, glutathione, CAT, SOD)",
        "Apoptosis (TUNEL-positive cells; apoptotic index)"
    ],
    "main_findings": "Histopathology showed normal Schwann cells and axons in all groups, but marked thickening of the epineurium in the EMF-exposed group. Biochemically, MDA, SOD, and CAT levels were higher in the EMF group than control and sham, and TUNEL(+) cells (apoptotic index) were significantly increased in the EMF group.",
    "effect_direction": "harm",
    "limitations": [
        "Animal study (male rats); human relevance not directly assessed",
        "Exposure described as 900 MHz EMF in an apparatus; dosimetry/SAR not reported in abstract",
        "Sample size per group is small (n=8)"
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "900 MHz",
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        "adolescence",
        "sciatic nerve",
        "oxidative stress",
        "malondialdehyde",
        "catalase",
        "superoxide dismutase",
        "TUNEL",
        "apoptosis",
        "epineurium thickening",
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