Study type: Medical/biological study (experimental study)

Chemoprotective action of lotus seedpod procyanidins on oxidative stress in mice induced by extremely low-frequency electromagnetic field exposure. med./bio.

Published in: Biomed Pharmacother 2016; 82: 640-648

Aim of study (acc. to author)

The effects of exposure of mice to a 50 Hz magnetic field on oxidative stress in the brain and serum and the protective effect of lotus seedpod procyanidins should be investigated.

Background/further details

In a previous study (Duan et al. 2013), the authors reported that lotus seedpod procyanidins (LSPCs) treatment prevented a magnetic field related increase in oxidation products and deficits in cognitive functions of mice, which suggested that LSPCs may have the potential to stimulate antioxidant enzyme activity and to scavenge oxygen free radicals.
First, the effect of different magnetic flux densities was investigated and male mice were divided into the following groups (n=12 each): exposure to a magnetic field of 1) 2 mT, 2) 4 mT, 3) 6 mT, 4) 8 mT, 5) 10 mT and 6) sham exposure for 7-28 days (4 h/day).
Secondly, the protective effect of LSPCs was investigated. LSPC extracts were administered orally once per day 15 days prior to and during exposure. Male mice were divided into the following groups (n=12 each): 7) exposure to an 8 mT magnetic field for 28 days (4 h/day) and oral saline administration, 8) exposure and 60 mg/kg LSPCs, 9) exposure + 90 mg/kg LSPCs, 10) exposure + 120 mg/kg LSPCs, 11) sham exposure.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: continuous for 7, 14, 21 and 28 days (4 h/day)
Exposure 2: 50 Hz
Exposure duration: continuous for 7, 14, 21 and 28 days (4 h/day)
Exposure 3: 50 Hz
Exposure duration: continuous for 7, 14, 21 and 28 days (4 h/day)
Exposure 4: 50 Hz
Exposure duration: continuous for 7, 14, 21 and 28 days (4 h/day)
Exposure 5: 50 Hz
Exposure duration: continuous for 7, 14, 21 and 28 days (4 h/day)

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Exposure duration continuous for 7, 14, 21 and 28 days (4 h/day)
Exposure setup
Exposure source
Chamber ventilated perspex boxes of dimensions 14 cm x 10 cm x 12 cm in a room at a controlled temperature (23°C ± 2°C)
Setup the magnetic field was generated with a pair of Helmholtz coils (1.0 mm wire diameter, 32 cm internal diameter, 36 cm external diameter, 500 turns) placed vertically to the ground; mice were placed in the boxes in the middle of the pair of coils, but the box was not in contact with the coils; the temperature inside the ventilated perspex box was 23°C ± 0.5°C
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 2 mT - measured - -

Exposure 2

Main characteristics
Frequency 50 Hz
Type
Exposure duration continuous for 7, 14, 21 and 28 days (4 h/day)
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 4 mT - measured - -

Exposure 3

Main characteristics
Frequency 50 Hz
Type
Exposure duration continuous for 7, 14, 21 and 28 days (4 h/day)
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 6 mT - measured - -

Exposure 4

Main characteristics
Frequency 50 Hz
Type
Exposure duration continuous for 7, 14, 21 and 28 days (4 h/day)
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 8 mT - measured - -

Exposure 5

Main characteristics
Frequency 50 Hz
Type
Exposure duration continuous for 7, 14, 21 and 28 days (4 h/day)
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 10 mT - measured - -

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

28 days of exposure to an 8 mT (group 4) and 10 mT (group 5) field showed the most distinct significant decreases in SOD enzyme activity and most distinct significant increase in lipid peroxidation compared to the sham exposure. For energy saving and safety reasons, 8 mT for 28 days was chosen as exposure conditions for further tests with LSPCs.
Body weight was significantly decreased after exposure (group 7) compared to the sham exposure group (group 11) after 28 days of exposure. Additional treatment with 120 mg/kg LSPCs (group 10) significantly increased the body weight after 28 days of exposure compared to group 7.
After 28 days, the enzyme activities of all antioxidant enzymes in serum and cerebral cortex were significantly decreased in group 7 compared to the sham exposure group and they were significantly increased in group 10 compared to group 7. Likewise, lipid peroxidation was significantly increased in serum and cerebral cortex of group 7 compared to the sham exposure group and it was significantly decreased in group 10 compared to group 7 after 28 days.
In histological examinations, alterations and significant tissue damage were observed in cerebral cortex, thymus and spleen samples from group 7 after 28 days compared to the sham exposure group. These changes were attenuated in LSPC treatment groups (groups 8-10).
The authors conclude that exposure of mice to a 50 Hz magnetic field might induce oxidative stress in the brain and serum and that lotus seedpod procyanidins could have a protective effect.

Study character:

Study funded by

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