Effect of Exposure to Static, High Voltage Electric Field Generated Nearby HVDC Transmission Lines on Antioxidant Activity of Hepatocytes in Rats

The effect of long-term, whole-body exposure to strong, static electric field generated usually nearby high voltage direct current (HVDC) transmission lines on activity of some antioxidant enzymes in homogenats of liver tissue of rats was investigated in this study. Experimental material consisted of 64 male Wistar albino rats aged 8 weeks, weighting 180-200g. During the whole experiment all animals were placed in identical environmental conditions under a 12 h light-dark cycle with free access to standard laboratory pellet food and tap water. All animals were randomly divided into 2 groups (32 animals each). The rats from experimental group were exposed for 56 consecutive days (8 hours daily) to static electric field with electric field intensity values of 25 kV/m (usually measured nearby actually existing HVDC transmission lines), in a specially designed experimental system. The control animals were subjected to a sham-exposure in the same experimental system, during which no electric field was generated between electrodes. At 14th, 28th and 56th day of exposure cycle and then in 28th day after the end of exposure cycle a part of animals from all groups (8 rats at a same time) was exsanguinated in Morbital narcosis. Then in homogenats prepared from obtained liver samples the activity of some antioxidant enzymes as catalase, glutathione S transferase, glutathione permddase, glutathione reductase and superoxide dismutase was determined with use of spectrophotometric methods as well as the concentration of malone dialdehyde (marker of intensity of oxidative processes in tissues) was estimated. As a result of repeated exposures in experimental electric field-exposed group of rats a significant increase in activity of glutathione peroxidase and glutathione reductase at 56th day of exposure cycle, a significant decrease in superoxide dysmutase activity at 14th day of exposure cycle as well as no statistically significant changes in activity of catalase and glutathione 5-transferase both during and after the end of exposure cycle were observed. Moreover in experimental group of rats a significant decrease in malone dialdehyde concentration in homogenats of liver tissue at 28th day after the end of exposure cycle as compared to control rats was observed. On the basis of obtained results it was concluded that strong static electric fields with parameters generated usually nearby high voltage direct current transmission lines does not cause any persistent unfavorable effect on antioxidant reactions in the liver of rodents. These data indicate that proper construction of high voltage direct current transmission lines enables to avoid serious health hazards for human population related to disturbances of antioxidant processes in living organisms.