Exposure to 900 MHz electromagnetic fields activates the mkp-1/ERK pathway and causes blood-brain barrier damage and cognitive impairment in rats

Brain Res · 2015 · Harm · Low evidence

← Research stream

HarmLow evidencePaper 2437

Study snapshot

PublicationBrain Res · 2015

Study typeanimal

Reported directionHarm

Evidence ratingLow

Abstract

With the rapid increase in the number of mobile phone users, the potential adverse effects of the electromagnetic field radiation emitted by a mobile phone has become a serious concern. This study demonstrated, for the first time, the blood-brain barrier and cognitive changes in rats exposed to 900 MHz electromagnetic field (EMF) and aims to elucidate the potential molecular pathway underlying these changes. A total of 108 male Sprague-Dawley rats were exposed to a 900 MHz, 1 mW/cm2 EMF or sham (unexposed) for 14 or 28 days (3 h per day). The specific energy absorption rate (SAR) varied between 0.016 (whole body) and 2 W/kg (locally in the head). In addition, the Morris water maze test was used to examine spatial memory performance determination. Morphological changes were investigated by examining ultrastructural changes in the hippocampus and cortex, and the Evans Blue assay was used to assess blood brain barrier (BBB) damage. Immunostaining was performed to identify heme oxygenase-1 (HO-1)-positive neurons and albumin extravasation detection. Western blot was used to determine HO-1 expression, phosphorylated ERK expression and the upstream mediator, mkp-1 expression. We found that the frequency of crossing platforms and the percentage of time spent in the target quadrant were lower in rats exposed to EMF for 28 days than in rats exposed to EMF for 14 days and unexposed rats. Moreover, 28 days of EMF exposure induced cellular edema and neuronal cell organelle degeneration in the rat. In addition, damaged BBB permeability, which resulted in albumin and HO-1 extravasation were observed in the hippocampus and cortex. Thus, for the first time, we found that EMF exposure for 28 days induced the expression of mkp-1, resulting in ERK dephosphorylation. Taken together, these results demonstrated that exposure to 900 MHz EMF radiation for 28 days can significantly impair spatial memory and damage BBB permeability in rat by activating the mkp-1/ERK pathway.

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 directionharm

PopulationMale Sprague-Dawley rats

Sample size108

ExposureRF · 900 MHz · 2 W/kg · 14 or 28 days (3 h/day)

Evidence strengthLowConfidence: 86% · Peer reviewed: yes

Main findings

Rats exposed to 900 MHz EMF for 28 days showed worse Morris water maze performance (lower platform crossings and less time in target quadrant) than rats exposed for 14 days and sham controls. After 28 days, ultrastructural changes (cellular edema and organelle degeneration) and increased BBB permeability with albumin and HO-1 extravasation were observed in hippocampus and cortex. EMF exposure for 28 days increased mkp-1 expression and was associated with ERK dephosphorylation.

Outcomes measured

Spatial memory performance (Morris water maze)
Blood-brain barrier (BBB) permeability/damage (Evans Blue assay, albumin extravasation)
Hippocampus and cortex ultrastructural/morphological changes
HO-1-positive neurons and HO-1 expression
Phosphorylated ERK expression
mkp-1 expression

Limitations

Animal study; generalizability to humans not addressed in abstract
Exposure intensity reported as 1 mW/cm^2 with SAR ranging from 0.016 (whole body) to 2 W/kg (local head); detailed dosimetry and distribution not provided in abstract
Mechanistic pathway inference based on measured markers; causality not fully established in abstract

View raw extracted JSON

{
  "study_type": "animal",
  "exposure": {
    "band": "RF",
    "source": "mobile phone",
    "frequency_mhz": 900,
    "sar_wkg": 2,
    "duration": "14 or 28 days (3 h/day)"
  },
  "population": "Male Sprague-Dawley rats",
  "sample_size": 108,
  "outcomes": [
    "Spatial memory performance (Morris water maze)",
    "Blood-brain barrier (BBB) permeability/damage (Evans Blue assay, albumin extravasation)",
    "Hippocampus and cortex ultrastructural/morphological changes",
    "HO-1-positive neurons and HO-1 expression",
    "Phosphorylated ERK expression",
    "mkp-1 expression"
  ],
  "main_findings": "Rats exposed to 900 MHz EMF for 28 days showed worse Morris water maze performance (lower platform crossings and less time in target quadrant) than rats exposed for 14 days and sham controls. After 28 days, ultrastructural changes (cellular edema and organelle degeneration) and increased BBB permeability with albumin and HO-1 extravasation were observed in hippocampus and cortex. EMF exposure for 28 days increased mkp-1 expression and was associated with ERK dephosphorylation.",
  "effect_direction": "harm",
  "limitations": [
    "Animal study; generalizability to humans not addressed in abstract",
    "Exposure intensity reported as 1 mW/cm^2 with SAR ranging from 0.016 (whole body) to 2 W/kg (local head); detailed dosimetry and distribution not provided in abstract",
    "Mechanistic pathway inference based on measured markers; causality not fully established in abstract"
  ],
  "evidence_strength": "low",
  "confidence": 0.86,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "900 MHz",
    "RF-EMF",
    "rats",
    "Sprague-Dawley",
    "blood-brain barrier",
    "cognition",
    "Morris water maze",
    "hippocampus",
    "cortex",
    "Evans Blue",
    "albumin extravasation",
    "HO-1",
    "mkp-1",
    "ERK"
  ],
  "suggested_hubs": [
    {
      "slug": "mobile-phones",
      "weight": 0.9,
      "reason": "Motivated by mobile phone RF exposure; 900 MHz RF-EMF used."
    },
    {
      "slug": "blood-brain-barrier",
      "weight": 0.85,
      "reason": "Assessed BBB permeability and albumin extravasation; reports BBB damage."
    },
    {
      "slug": "animal-studies",
      "weight": 0.8,
      "reason": "In vivo rat exposure experiment."
    }
  ]
}

AI can be wrong. Always verify against the paper.

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.brainres.2015.01.019
PubMed: Not supplied

Read the original paper →

Related papers

← Back to the Research Library