Study type: Medical/biological study (experimental study)

Can static electric fields increase the activity of nitric oxide synthase and induce oxidative stress and damage of spleen? med./bio.

Published in: Environ Sci Pollut Res Int 2021 [in press]

Aim of study (acc. to author)

To study the effects of static electric fields on the spleen of mice.

Background/further details

With the development of high-voltage direct current (HVDC) power lines, the impact of static electric fields in the vicinity of these power lines on health has attracted public concern. With the increase of HVDC power lines, the authors deemed it necessary to study the effects of static electric fields on spleen. The spleen was investigated because of its role in activating and controlling the immune response.
68 mice were randomly divided into a control group (n=34) and an exposure group (n=34). The oxidative stress indices in the spleens of mice were determined after the exposure of 7, 14, and 21 days, respectively (n=10 mice per group). The cellular ultrastructure of the spleens was investigated after 21 days (n=4 mice per group).

Endpoint

Exposure

Exposure Parameters
Exposure 1:
Exposure duration: continuously for 21 days

General information

Temperature and humidity were maintained at 22 ± 2°C and 50~60%. Mice were raised in plastic buckets (35 cm × 25 cm × 46 cm). Temperature, humidity, noise, and ventilation inside the buckets of exposure group were the same as those inside the buckets of the control group. The electric potential of the mouth of the water bottle was about 2.3 kV. The plastic bucket was an insulating medium, i.e. there was an insulation between the mice in the bucket and the grounded lower plate. Therefore, the electric potential would not cause micro-discharges, according to the authors.

Exposure 1

Main characteristics
Frequency
Type
Exposure duration continuously for 21 days
Exposure setup
Exposure source
Setup Exposure device was composed of a controller, a booster system, and upper and lower plates. The diameter of the two plates was 1 m. The plastic buckets of the control group were placed on the ground below the lower plate. The theoretical strength of the static electric field between the lower plate and the ground was 0 kV/m because the lower plate was grounded. The plastic buckets of the exposure group were also placed on the lower plate and exposed to the static electric field.
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 56.3 kV/m - - - 56.3 kV/m is 2.3 times of the limit value in China

Reference articles

  • Xu Y et al. (2018): Duration-dependent effect of exposure to static electric field on learning and memory ability in mice.
  • Wu S et al. (2017): Does static electric field from ultra-high voltage direct-current transmission lines affect male reproductive capacity? Evidence from a laboratory study on male mice.

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

The data showed that the static electric field exposure of 21 days significantly increased the malondialdehyde level, the enzyme activities of superoxide dismutase, calcineurin, nitric oxide synthase, and the mRNA expression levels of tumor necrosis factor-α and nuclear factor kappa B in the spleen and caused the separation of nucleus and nuclear membrane, the disappearance of mitochondrial membrane, and the deficiency of mitochondrial cristae in splenic lymphocytes.
The authors concluded that the static electric field could induce oxidative stress of the spleen by increasing the enzyme activity of nitric oxide synthase. Oxidative stress could further cause ultrastructural changes of splenic lymphocytes. Moreover, oxidative stress could cause the increase of the mRNA expression levels of tumor necrosis factor-α and tumor nuclear factor kappa B, which contributed to the occurrence of spleen inflammation.

Study character:

Study funded by

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