PubMed · 2010 · 63 citations · 24 references
Life SciencesPhysiologyToxicologyElectromagneticsElectromagnetismRedox BiochemistryAntioxidant DefenseLipid PeroxidationOxidative Damage To BiomoleculesOxidative StressOxidative Stress MechanismsReactive Oxygen SpeciesAntioxidant Capacity AssaysHydrogen Peroxide GenerationMagnetic Field ExposureOxidative Stress In Cardiovascular DiseaseOxidative Stress InjuryReactive Oxygen Species GenerationReactive Oxygen Species InjuryThiobarbituric Acid Reactive Substances
Free radical production is a proposed mechanism by which extremely low‑frequency magnetic fields may influence biological systems. This study examined whether magnetotherapy‑level ELF‑MF exposure alters reactive oxygen species generation in heart tissue and plasma antioxidant capacity over time. Rats were divided into a control group and two exposure groups (40 Hz, 7 mT for 30 min/day or 60 min/day over 14 days); oxidative stress markers (TBARS, H₂O₂, free‑SH, GSH) were measured in heart homogenates and plasma FRAP was assessed. Thirty‑minute daily exposure had no significant effect, whereas 60‑minute daily exposure increased TBARS and H₂O₂, reduced GSH and free‑SH, and lowered plasma antioxidant capacity, indicating time‑dependent effects of ELF‑MF on cardiac oxidative stress.
Increasing production of free radicals in organisms is one of the putative mechanisms by which a extremely low frequency magnetic field (ELF-MF) may affect biological systems. The present study was designated to assess if ELF-MF applied in the magnetotherapy, affects generation of reactive oxygen species (ROS) in heart tissue and antioxidant capacity of plasma according to its working time. The experiments were performed on 3 groups of animals: group I - control; group II - exposed to 40 Hz, 7 mT, 30 min/day for 14 days (this field is commonly applied in magnetotherapy); group III - exposed to 40 Hz, 7 mT, 60 min/day for 14 days. Control rats were housed in a separate room without exposure to ELF-MF. Immediately after the last exposure, blood was taken from the tail vein and hearts were removed under anesthesia. The effect of the exposure to ELF-MF on oxidative stress was assessed on the basis of the measurements of thiobarbituric acid reactive substances (TBARS), hydrogen peroxide (H(2)O(2)), total free sulphydryl groups (-SH groups) and reduced glutathione (GSH) concentrations in heart homogenates. The total antioxidant capacity of plasma was measured using ferric reducing ability method (FRAP). Exposure to ELF-MF (40 Hz, 7 mT, 30 min/day for 2 weeks) did not significantly alter tissue TBARS, H(2)O(2), total free -SH groups, reduced glutathione (GSH) and total antioxidant capacity of plasma. By contrast, ELF-MF with the same frequency and induction but used for 60 min/day for 14 days caused significant increase in TBARS and H(2)O(2) concentration (P<0.01) and decrease in the concentration of GSH (P<0.05) and total free -SH groups in heart homogenates. Moreover, exposure of rats to ELF-MF (40 Hz, 7 mT, 60 min/day for 2 weeks) resulted in the decrease of plasma antioxidant capacity. Our results indicate that effects of ELF-MF on ROS generation in the heart tissue and antioxidant capacity of plasma depend on its working time.
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George L. Ellman · Archives of Biochemistry and Biophysics · 1959 · 26.2K citations
Helena M. Viola, Peter G. Arthur, Livia C. Hool · Circulation Research · 2007 · 132 citations · Full text