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[Effects of 1.8 mT sinusoidal alternating electromagnetic fields of different frequencies on bone biomechanics of young rats].

Zhejiang da xue xue bao. Yi xue ban = Journal of Zhejiang University. Medical sciences · 2016 · Benefit · Low evidence

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In 32 young female rats exposed to 1.8 mT sinusoidal alternating electromagnetic fields (10, 25, or 40 Hz) for 90 min/day, the 10 Hz and 40 Hz groups showed significantly higher whole-body and femur BMD and improved femur and lumbar vertebra biomechanical mea…

Study snapshot

PublicationZhejiang da xue xue bao. Yi xue ban = Journal of Zhejiang University. Medical sciences · 2016
Study typeanimal
Reported directionBenefit
Evidence ratingLow

Abstract

To study the effects of 1.8 mT sinusoidal electromagnetic fields of different frequencies on bone mineral density (BMD) and biomechanical properties in young rats. A total of 32 female SD rats (6-week-old) were randomly divided into 4 groups (8 in each):control group, 10 Hz group, 25 Hz group and 40 Hz group. The experimental groups were given 1.8 mT sinusoidal electromagnetic field intervention 90 min per day. The whole body BMD of rats was detected with dual-energy X-ray absorptiometry after 4 and 8 weeks of intervention. After 8 weeks of intervention, all rats were sacrificed, and the BMD of femur and lumbar vertebra, the length and diameter of femur, the width between medial and lateral malleolus were measured. Electronic universal material testing machine was used to obtain biomechanical properties of femur and lumbar vertebra, and micro CT scan was performed to observe micro structures of tibial cancellous bone. Compared with the control group, rats in 10 Hz and 40 Hz groups had higher whole body BMD, BMD of femur, maximum load and yield strength of femur, as well as maximum load and elastic modulus of lumbar vertebra (all <0.05). But no significant differences in the length and diameter of femur, and the width between medial and lateral malleolus were observed between control group and experimental groups (all >0.05). Micro CT scan showed that the trabecular number and separation degree, bone volume percentage were significantly increased in 10 Hz and 40 Hz groups (all <0.01). Rats in 25 Hz group also had higher BMD and better in biomechanical properties than control group, but the differences were not statistically significant (all >0.05). 10 and 40 Hz of 1.8 mT sinusoidal electromagnetic field can significantly improve the bone density, microstructure and biomechanical properties in young rats.

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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 directionbenefit
PopulationYoung female Sprague-Dawley rats (6-week-old)
Sample size32
ExposureELF · 90 min/day for 4 and 8 weeks (measurements at 4 and 8 weeks; sacrifice at 8 weeks)
Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

In 32 young female rats exposed to 1.8 mT sinusoidal alternating electromagnetic fields (10, 25, or 40 Hz) for 90 min/day, the 10 Hz and 40 Hz groups showed significantly higher whole-body and femur BMD and improved femur and lumbar vertebra biomechanical measures versus controls. Micro-CT measures (trabecular number, separation degree, bone volume percentage) were also significantly increased in the 10 Hz and 40 Hz groups; the 25 Hz group showed non-significant improvements.

Outcomes measured

  • Whole body bone mineral density (BMD)
  • Femur BMD
  • Lumbar vertebra BMD
  • Femur biomechanics (maximum load, yield strength)
  • Lumbar vertebra biomechanics (maximum load, elastic modulus)
  • Femur length and diameter
  • Width between medial and lateral malleolus
  • Tibial cancellous bone microstructure by micro-CT (trabecular number, separation degree, bone volume percentage)

Limitations

  • Animal study (young female rats), limiting direct generalization to humans
  • Exposure duration and total study length limited to 8 weeks
  • Only one field intensity tested (1.8 mT)
  • Some outcomes in the 25 Hz group were not statistically significant
View raw extracted JSON
{
  "study_type": "animal",
  "exposure": {
    "band": "ELF",
    "source": null,
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": "90 min/day for 4 and 8 weeks (measurements at 4 and 8 weeks; sacrifice at 8 weeks)"
  },
  "population": "Young female Sprague-Dawley rats (6-week-old)",
  "sample_size": 32,
  "outcomes": [
    "Whole body bone mineral density (BMD)",
    "Femur BMD",
    "Lumbar vertebra BMD",
    "Femur biomechanics (maximum load, yield strength)",
    "Lumbar vertebra biomechanics (maximum load, elastic modulus)",
    "Femur length and diameter",
    "Width between medial and lateral malleolus",
    "Tibial cancellous bone microstructure by micro-CT (trabecular number, separation degree, bone volume percentage)"
  ],
  "main_findings": "In 32 young female rats exposed to 1.8 mT sinusoidal alternating electromagnetic fields (10, 25, or 40 Hz) for 90 min/day, the 10 Hz and 40 Hz groups showed significantly higher whole-body and femur BMD and improved femur and lumbar vertebra biomechanical measures versus controls. Micro-CT measures (trabecular number, separation degree, bone volume percentage) were also significantly increased in the 10 Hz and 40 Hz groups; the 25 Hz group showed non-significant improvements.",
  "effect_direction": "benefit",
  "limitations": [
    "Animal study (young female rats), limiting direct generalization to humans",
    "Exposure duration and total study length limited to 8 weeks",
    "Only one field intensity tested (1.8 mT)",
    "Some outcomes in the 25 Hz group were not statistically significant"
  ],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "sinusoidal alternating electromagnetic field",
    "1.8 mT",
    "10 Hz",
    "25 Hz",
    "40 Hz",
    "bone mineral density",
    "biomechanics",
    "micro-CT",
    "rats"
  ],
  "suggested_hubs": [
    {
      "slug": "animal-studies",
      "weight": 0.9,
      "reason": "Controlled exposure experiment in young rats assessing bone outcomes."
    }
  ]
}
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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: 10.3785/j.issn.1008-9292.2016.11.01
PubMed: 28247597

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