The experiment consisted of two halves of 60 minutes, each: The first half was to investigate time-dependent changes of glucocorticoid and other blood parameters due to exposure and/or immobilization. Mice in the respective groups were exposed to the electric field during the complete first 60 minutes. In the second half, potential recovery from the treatments was assessed.
Four groups of mice were examined: 1) control group, 2) electric field exposure, 3) immobilization, and 4) electric field exposure + immobilization. Groups 1 and 2 consisted of ten sub-groups* (n=8 per sub-group) to allow blood sampling every ten minutes during the first 60 minutes of the experiment and every 20 minutes during the recovery period. Groups 3 and 4 consisted of seven sub-groups*, respectively to allow blood sampling every ten minutes after initiation of immobilization and every 20 minutes during the recovery period.
*Remark EMF-Portal: Smaller numbers of sub-group numbers given in the running text of the materials and methods section of the article (groups 1 and 2 are stated to consist of seven sub-groups, and groups 3 and 4 of three sub-groups). However, bigger numbers shown in the results section seem more consistent and logical.
|Chamber||mice were exposed in a cylindrical plastic cage (diameter 200 mm, height 50-200 mm) with slits to prevent smudges from saliva or feces which could disturb the electric field|
|Setup||two stainless steel electrodes (1000 x 600 mm) that were placed over and under the cylindrical cage were used; to generate the EF in the cage, a voltage of 1 kV was applied to the upper electrode, and the counterpart electrode was grounded; electric field strength had a margin of error of ± 1%; temperature did not change due to electric field; humidity was kept between 45% and 55%|
No time-dependent changes of the glucocorticoid level were seen in the control group (group 1) and the electric field exposure group (group 2). In immobilized mice alone (group 3) and in immobilized + exposed mice (group 4), the plasma glucocorticoid level showed increasing trends during the immobilization. However, only the values of group 3 were significant as compared to the control group. In the recovery period, the plasma glucocorticoid level decreased in groups 3 and 4 (Remark EMF-Portal: stated to be significant, but not clear compared to what).
No significant changes were found in the other blood parameters.
The authors conclude that the electric field reduced the immobilization-induced changes in the glucocorticoid level without temporal shifting of the peak and could therefore reduce the stress level in mice.