Effects of extremely low frequency magnetic field on oxidative balance in brain of rats.

TLDR

Extremely low frequency magnetic field (ELF‑MF) can induce oxidative DNA damage and lipid peroxidation, potentially leading to systemic disturbances and cell death. The study aims to determine how ELF‑MF parameters commonly used in magnetotherapy affect reactive oxygen species generation in rat brain tissue over varying exposure times. Adult male Sprague‑Dawley rats (3–4 months) were assigned to a sham control or to two exposure groups (7 mT, 40 Hz, 30 min/day or 60 min/day for 10 days), and oxidative stress markers (TBARS, H₂O₂, total free sulfhydryl groups, and protein) were measured in brain homogenates. Exposure to 7 mT, 40 Hz for 30 min/day increased lipid peroxidation and modestly raised H₂O₂ and free‑SH groups, whereas 60 min/day increased free‑SH groups and protein, indicating an adaptive response; overall, the effect of ELF‑MF on oxidative stress depends on exposure duration.

Abstract

Extremely low frequency magnetic field (ELF-MF) may result in oxidative DNA damage and lipid peroxidation with an ultimate effect on a number of systemic disturbances and cell death. The aim of the study is to assess the effect of ELF-MF parameters most frequently used in magnetotherapy on reactive oxygen species generation (ROS) in brain tissue of experimental animals depending on the time of exposure to this field. The research material included adult male Sprague-Dawley rats, aged 3-4 months. The animals were divided into 3 groups: I - control (shame) group; II - exposed to the following parameters of the magnetic field: 7 mT, 40 Hz, 30 min/day, 10 days; III - exposed to the ELF-MF parameters of 7 mT, 40 Hz, 60 min/day, 10 days. The selected parameters of oxidative stress: thiobarbituric acid reactive substances (TBARS), hydrogen peroxide (H(2)O(2)), total free sulphydryl groups (-SH groups) and protein in brain homogenates were measured after the exposure of rats to the magnetic field. ELF-MF parameters of 7 mT, 40 Hz, 30 min/day for 10 days caused a significant increase in lipid peroxidation and insignificant increase in H(2)O(2) and free -SH groups. The same ELF-MF parameters but applied for 60 min/day caused a significant increase in free -SH groups and protein concentration in the brain homogenates indicating the adaptive mechanism. The study has shown that ELF-MF applied for 30 min/day for 10 days can affect free radical generation in the brain. Prolongation of the exposure to ELF-MF (60/min/day) caused adaptation to this field. The effect of ELF-MF irradiation on oxidative stress parameters depends on the time of animal exposure to magnetic field.