Photoperiodism as a modifier of effect of extremely low-frequency electromagnetic field on morphological properties of pineal gland.

Bosnian journal of basic medical sciences · 2006 · Mixed · Low evidence

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MixedLow evidencePaper 5101

Study snapshot

PublicationBosnian journal of basic medical sciences · 2006

Study typeanimal

Reported directionMixed

Evidence ratingLow

Abstract

The aim of our study was to determine, using histological and stereological methods, whether photoperiodism has any impact on the effects that chronic (three-month long) exposure to LF-EMF (50Hz) has on morphological characteristics on rat's pineal gland. The experiment was performed on 48 Mill Hill male rats (24 experimental and 24 control). Upon birth, 24 rats were exposed for 7h a day, 5 days a week for 3 months to LF-EMF (50 Hz, 50-500microT, 10V/m). In the winter (short days, long nights), the activity of the pineal gland and neuroendocrine sensitivity is increased. The study was performed both during summer and winter, following the identical protocol. After sacrifice of animals, samples of pineal gland were processed for HE staining and then were analyzed using the methods of stereology. The most significant changes in epiphysis in the first group of animals in wintertime are: altered glandular feature, hyperemia, reduced pinealocytes with pale pink, poor cytoplasm and irregular, stick-form nuclei. In the second group (II) pinealocytes are enlarged, with vacuolated cytoplasm and hyper chromatic, enlarged nucleus. Morphological changes of pineal gland at rats in the summertime were not as intense as in the winter and finding of the gland in the group II is compatible with those from the control group. Stereological results show both in winter and summer in the first group the decrease of volume density of pinealocytes, their cytoplasm and nuclei and in the second group in winter increase the volume density of pinealocytes, cytoplasm and nuclei, while in the second group the results in summertime are equal to those from the control group. Photoperiodism is modifier of effect of LF-EMF on morphological structure of pineal gland, because the gland recovery is incomplete in winter and reversible in summer.

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AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typeanimal

Effect directionmixed

PopulationMill Hill male rats

Sample size48

ExposureELF · 0.05 MHz · 7 h/day, 5 days/week for 3 months (chronic exposure from birth)

Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

Chronic 50 Hz LF-EMF exposure was associated with morphological and stereological changes in rat pineal gland, with effects described as more intense in winter than summer. In winter, one exposed group showed altered glandular features, hyperemia, and reduced pinealocytes with abnormal cytoplasm/nuclei; another exposed group showed enlarged pinealocytes with vacuolated cytoplasm and enlarged hyperchromatic nuclei. In summer, changes were less intense and one exposed group was reported as compatible with controls; authors conclude photoperiodism modifies LF-EMF effects with incomplete recovery in winter and reversibility in summer.

Outcomes measured

Pineal gland morphological characteristics (histology)
Stereological measures (volume density of pinealocytes, cytoplasm, nuclei)
Season/photoperiod-related modification of effects (winter vs summer)

Limitations

Exposure source/setup not described beyond field parameters (50–500 microT, 10 V/m)
Group definitions (e.g., what distinguishes group I vs group II) are not clearly explained in the abstract
No quantitative statistics or effect sizes reported in the abstract
Animal study; generalizability to humans is limited

View raw extracted JSON

{
  "study_type": "animal",
  "exposure": {
    "band": "ELF",
    "source": null,
    "frequency_mhz": 0.05,
    "sar_wkg": null,
    "duration": "7 h/day, 5 days/week for 3 months (chronic exposure from birth)"
  },
  "population": "Mill Hill male rats",
  "sample_size": 48,
  "outcomes": [
    "Pineal gland morphological characteristics (histology)",
    "Stereological measures (volume density of pinealocytes, cytoplasm, nuclei)",
    "Season/photoperiod-related modification of effects (winter vs summer)"
  ],
  "main_findings": "Chronic 50 Hz LF-EMF exposure was associated with morphological and stereological changes in rat pineal gland, with effects described as more intense in winter than summer. In winter, one exposed group showed altered glandular features, hyperemia, and reduced pinealocytes with abnormal cytoplasm/nuclei; another exposed group showed enlarged pinealocytes with vacuolated cytoplasm and enlarged hyperchromatic nuclei. In summer, changes were less intense and one exposed group was reported as compatible with controls; authors conclude photoperiodism modifies LF-EMF effects with incomplete recovery in winter and reversibility in summer.",
  "effect_direction": "mixed",
  "limitations": [
    "Exposure source/setup not described beyond field parameters (50–500 microT, 10 V/m)",
    "Group definitions (e.g., what distinguishes group I vs group II) are not clearly explained in the abstract",
    "No quantitative statistics or effect sizes reported in the abstract",
    "Animal study; generalizability to humans is limited"
  ],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "extremely low-frequency electromagnetic field",
    "ELF-EMF",
    "50 Hz",
    "pineal gland",
    "photoperiodism",
    "winter",
    "summer",
    "histology",
    "stereology",
    "rats"
  ],
  "suggested_hubs": [
    {
      "slug": "animal-studies",
      "weight": 0.9,
      "reason": "Rat experiment assessing ELF-EMF effects on pineal gland morphology."
    }
  ]
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.17305/bjbms.2006.3136
PubMed: 16995841

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