Study type: Medical/biological study (experimental study)

Effect of exposure to 50 Hz magnetic field with or without insulin on blood-brain barrier permeability in streptozotocin-induced diabetic rats. med./bio.

Published in: Bioelectromagnetics 2010; 31 (4): 262-269

Aim of study (acc. to author)

To study the effect of long-term exposure to a modulated magnetic field, insulin, and their combination on blood-brain barrier permeability (30 days after the beginning of the experiments) in a diabetic rat model.

Background/further details

The effects of diabetes mellitus on the blood-brain barrier are contradictory.
53 rats were randomly assigned to one of six groups: 1) sham exposure; 2) magnetic field exposure; 3) diabetes mellitus induced with streptozotocin; 4) diabetes mellitus plus magnetic field exposure; 5) diabetes mellitus plus insulin therapy; and 6) diabetes mellitus plus insulin therapy plus magnetic field exposure.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: 30 min on - 15 min off for 165 min/day on 30 days

General information

rats were divided into six groups: i) sham exposure ii) EMF exposure iii) diabetes mellitus induced iv) diabetes mellitus induced + EMF exposure v) diabetes mellitus induced + insulin therapy vi) diabetes mellitus induced + insulin therapy + EMF exposure

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration 30 min on - 15 min off for 165 min/day on 30 days
Exposure setup
Exposure source
Setup 500 mm long solenoid with a diameter of 210 mm, construced of 140 turns of 1.4 mm insulated soft copper wire wound around a fiber base; rats placed in a 40 cm x 17 cm x 13 cm Plexiglas cage inside the solenoid
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 5 mT - measured and calculated - inside the solenoid

Reference articles

  • Kavak S et al. (2009): Repetitive 50 Hz pulsed electromagnetic field ameliorates the diabetes-induced impairments in the relaxation response of rat thoracic aorta rings.

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Investigated organ system:
Time of investigation:
  • before exposure
  • after exposure

Main outcome of study (acc. to author)

The extravasation of evans blue of the groups 2-6 was higher than that of sham exposure group (group 1) and the extravasation of the right hemisphere of group 6 (diabetes mellitus plus insulin therapy plus magnetic field exposure) was the highest. The data showed that streptozotocin-induced diabetes mellitus appears to increase the vulnerability of the blood-brain barrier during magnetic field exposure.
A significant increase of mean arterial blood pressure was observed in all streptozotocin-induced diabetic rats, but the magnetic field caused no additional effect. The post-procedure body mass of the sham exposure and the exposure group (group 1 and 2) were significantly higher than those of the "diabetes mellitus group" and "diabetes mellitus plus magnetic field exposure group" (group 3 and 4). In the diabetic groups 3-6 the baseline glucose (before treatment) was significantly lower than the post-procedure glucose level.
Diabetes mellitus and magnetic field exposure increased blood-brain barrier permeability; in combination, they caused a higher increase in blood-brain barrier permeability, and insulin decreased their effect (it prevents the disturbing effect of magnetic field exposure). Improved glucose metabolism may prevent body mass loss and the hypoglycemic effect of magnetic field. Further studies are needed to evaluate the clinical relevance of the relationship of diabetes mellitus with or without insulin therapy and magnetic field exposure.

Study character:

Study funded by

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