The aim of the study was to investigate the effects of chronic unpredictable mild stress induced oxidative balance of rat’s brain exposed to extremely low frequency magnetic fields (ELF-MF) to assess if mild stress influences the response to magnetic field exposure.
The chronic unpredictable mild stress (CUMS) model consisted of applying randomly a different kind of mild stressor each day for 21 days: movement restriction for 2 h, 4°C temperature exposure, the combination of both, forced swimming for 15 min, 45° cage tilting for 2 h, food deprivation for 24 h, water deprivation for 18 h, and isolation for 48 h.
Six groups of rats were used (each group n=8): 1) control condition for 21 days, 2) control condition for 14 days and then for 7 days ELF-MF exposure, 3) CUMS for 21 days, 4) CUMS for 21 days and the last 7 days co-exposed to ELF-MF, 5) CUMS for 14 days and then for 7 days ELF-MF exposure, 6) CUMS for 14 days and the next 7 days without any treatment.
Exposure duration: 2 h per day for 7 days
|magnetic flux density||2.4 mT||-||measured||-||-|
There was no statistically significant difference in oxidative stress parameters in the cerebellum of the different groups. However, a significant increase in the catalase enzyme activity and reduced glutathione concentration in the cerebrum of animals with CUMS for 14 days and subsequent exposure to ELF-MF for 7 days (group 5) was found compared to the other stressed groups. The same treatment decreased the lipid peroxidation.
The stressed animals that received concomitant ELF-MF exposure (group 4) showed an oxidative status like stressed animals by 21 days (group 3). Thus, no additional changes were observed in the CUMS induced-oxidative damage in the rat's cerebrum by the ELF-MF exposure.
In conclusion, the data showed that two weeks of CUMS induced oxidative damage in the rat´s cerebrum. ELF-MF exposure was able to reduce the oxidation elicited by the stressful condition when the magnetic field treatment was applied after removing the CUMS (group 5). The change in oxidative balance was not observed when the rats were at the same time co-exposed to stress and ELF-MF (group 4).