Changes in pyramidal and granular neuron numbers in rat hippocampus 7 days after exposure to continuous 900-MHz EMF during early and mid-adolescence

2019 · Mixed · Low evidence

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MixedLow evidencePaper 1723

Study snapshot

Publicationmanual · 2019

Study typeanimal

Reported directionMixed

Evidence ratingLow

Abstract

Changes in pyramidal and granular neuron numbers in rat hippocampus 7 days after exposure to continuous 900-MHz EMF during early and mid-adolescence Keleş Aİ, Nyengaard JR, Odacı E. Changes in pyramidal and granular neuron numbers in the rat hippocampus 7 days after exposure to a continuous 900-MHz electromagnetic field during early and mid-adolescence. J Chem Neuroanat. 2019 Aug 26:101681. doi: 10.1016/j.jchemneu.2019.101681. Abstract The aim of this study was to investigate qualitative and quantitative changes in pyramidal and granule neurons in the male rat hippocampus after exposure to a continuous 900-megahertz (MHz) electromagnetic field (EMF) for 25 days during early and mid-adolescence. Three-week-old (21 day) healthy Sprague Dawley male rats were divided equally into control (CON), pseudo-exposed (PEX) and EMF groups. EMF rats were exposed to a 900- MHz EMF in an EMF-application cage, while the PEX rats were placed in the same cage without being exposed to EMF. No procedure was performed in CON. EMF was applied for 1 h/day, every day for 25 days. Following the 900-MHz EMF and pseudo-exposed applications, behavioral tests were performed for seven days. Then, all animals were euthanized and their brains were removed. Following histological tissue procedures, sections were taken from tissues and stained with toluidine blue. The optical fractionation technique was performed to estimate the pyramidal neuron numbers in the CA1, CA2-3 and hilus regions of the hippocampus and granule neuron numbers in the dentate gyrus region. Our findings indicated that the number of pyramidal and granule neurons in the hippocampus of the EMF group was statistically higher than PEX. Furthermore, the histopathological results showed that the cytoplasm of pyramidal (in the hilus, CA1, CA2 and CA3 region) and granular (in the dentate gyrus region) cells at the hippocampus were disrupted, as evident by intensive staining around cytoplasm and some artifacts were detected in the EMF group. In addition, statistical comparisons of the mean body weights and brain weights of the study groups revealed no significant differences. There was no statistically significant difference between the PEX and EMF groups in terms of temperature (p > 0.05) or humidity (p > 0.05) in the cages. In conclusion, higher numbers of both pyramidal and granule neurons were found in the male rat hippocampus after continuous 900-MHz EMF treatment. ncbi.nlm.nih.gov

Machine Enhanced Logic

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

PopulationThree-week-old (21 day) healthy Sprague Dawley male rats (early and mid-adolescence exposure)

Sample sizeNot supplied

ExposureRF · 900 MHz · 1 h/day for 25 days; assessed 7 days after exposure (behavioral tests for 7 days)

Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

Pyramidal and granule neuron numbers in the hippocampus were statistically higher in the EMF group than in the pseudo-exposed group. Histopathology in the EMF group showed disrupted cytoplasm with intensive staining around cytoplasm and some artifacts in pyramidal and granular cells. Body and brain weights did not differ significantly between groups, and cage temperature/humidity did not differ between PEX and EMF.

Outcomes measured

Pyramidal neuron numbers in hippocampus (CA1, CA2-3, hilus)
Granule neuron numbers in dentate gyrus
Histopathological changes in hippocampal pyramidal and granular cells (toluidine blue staining)
Body weight
Brain weight
Cage temperature
Cage humidity

Limitations

Sample size not reported in the abstract
Only male rats studied
Exposure metric (e.g., SAR/power density) not reported in the abstract
Short follow-up (7 days after exposure)

View raw extracted JSON

{
  "study_type": "animal",
  "exposure": {
    "band": "RF",
    "source": "other",
    "frequency_mhz": 900,
    "sar_wkg": null,
    "duration": "1 h/day for 25 days; assessed 7 days after exposure (behavioral tests for 7 days)"
  },
  "population": "Three-week-old (21 day) healthy Sprague Dawley male rats (early and mid-adolescence exposure)",
  "sample_size": null,
  "outcomes": [
    "Pyramidal neuron numbers in hippocampus (CA1, CA2-3, hilus)",
    "Granule neuron numbers in dentate gyrus",
    "Histopathological changes in hippocampal pyramidal and granular cells (toluidine blue staining)",
    "Body weight",
    "Brain weight",
    "Cage temperature",
    "Cage humidity"
  ],
  "main_findings": "Pyramidal and granule neuron numbers in the hippocampus were statistically higher in the EMF group than in the pseudo-exposed group. Histopathology in the EMF group showed disrupted cytoplasm with intensive staining around cytoplasm and some artifacts in pyramidal and granular cells. Body and brain weights did not differ significantly between groups, and cage temperature/humidity did not differ between PEX and EMF.",
  "effect_direction": "mixed",
  "limitations": [
    "Sample size not reported in the abstract",
    "Only male rats studied",
    "Exposure metric (e.g., SAR/power density) not reported in the abstract",
    "Short follow-up (7 days after exposure)"
  ],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "rat",
    "hippocampus",
    "pyramidal neurons",
    "granule neurons",
    "dentate gyrus",
    "CA1",
    "CA2",
    "CA3",
    "hilus",
    "900 MHz",
    "RF EMF",
    "adolescence",
    "histopathology",
    "optical fractionation"
  ],
  "suggested_hubs": []
}

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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: 10.1016/j.jchemneu.2019.101681
PubMed: Not supplied

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