Effects of extremely low frequency magnetic field on the parameters of oxidative stress in heart

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 (h2o2),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,h2o2,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 h2o2 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.