Impact of electromagnetic field generated nearby high voltage alternating current transmission lines on prooxidant-antioxidant balance in selected internal organs of rats

In the study the impact of whole-body exposure to 50Hz electromagnetic field generated nearby those lines on prooxidant/antioxidant balance in selected internal organs of male rats was estimated, by means of analysis of the contents of markers of membrane lipid peroxidation and oxidative stress: malone dialdehyde (MDA) and total oxidant capacity (TOC), respectively, as well as the activity of antioxidant enzymes: superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione S-transferase (GST), in homogenates of kidney, heart and lung tissue. The experiment was performed on 20 male Wistar rats, in mean age of 10 weeks, divided into 2 equal groups (consisting of 10 animals), subjected to long-term exposure to electromagnetic field or to sham-exposure, respectively. Rats from examined group were exposed to electromagnetic field with physical parameters generated by typical high voltage electric current transmission lines (f = 50 Hz, E = 10 kV/m), 22 hours a day (with a break between 800 and 1000) for 28 succeeding days. Rats from control group were exposed for 28 succeeding days to sham-exposure, during which they stayed in identical as examined animals environmental conditions, excluding the influence of electromagnetic field. During the exposure rats were stayed in plastic cages placed between two round electrodes of experimental system supplied with an alternating current. After the end of a cycle of 28 daily exposures to electromagnetic field or sham-exposures (control rats), animals were starved by 24 hours, then anaesthetized and next the abdominal cavity was opened and samples of kidney, heart and lung were taken. In the homogenates prepared from the obtained samples the contents of TOC and MDA, as well as the activity of SOD, CAT, GPx, GR and GST were measured. The biochemical analyses were performed by means of routine spectrophotometric and kinetic methods. As a result of repeated exposures, in electromagnetic field-exposed group of rats in kidney tissue homogenates a significant increase in the contents of TOC and in the activity of SOD and GPx, as well as a significant decrease in the activity of GR and GST was observed, in heart tissue homogenates a significant decrease in the contents of TOC and in the activity of GST, as well as a significant increase in the activity of GPx was found, while in lung homogenates a significant increase in the contents of MDA and in the activity of CAT was confirmed, as compared to control sham-exposed rats. On the basis of the obtained results it was found, that 4-week lasting exposure of rats to electromagnetic field with physical parameters generated by high voltage alternating current transmission lines causes a slight intensification of oxidant processes in the tissue of examined internal organs with accompanying compensatory, multidirectional changes of antioxidant enzymes activity, enabling the maintenance of prooxidant/antioxidant balance only in heart tissue.