Effects of chronic exposure to 950 MHz ultra-high-frequency electromagnetic radiation on reactive oxygen species metabolism in the right and left cerebral cortex of young rats of different ages.

PURPOSE: To assess the effect of 950 MHz ultra-high-frequency electromagnetic radiation (UHF-EMR) on biomarkers of oxidative damage to DNA, proteins and lipids in the left cerebral cortex (LCC) and right cerebral cortex (RCC) of neonate and 6-day-old rats. MATERIALS AND METHODS: Twelve rats were equally divided into two groups as controls (CR) and exposed (ER), for each age (0 and 6 days). The LCC and RCC were examined in ER and CR after exposure. Radiation exposure lasted 30 min per day for up to 27 days (throughout pregnancy and 6 days postnatal). The specific absorption rate ranged from 1.32-1.14 W/kg. The damage to lipids, proteins and DNA was verified by thiobarbituric acid reactive substances, carbonylated proteins (CP) and comets, respectively. The concentration of glucose in the peripheral blood of the rats was measured by the Accu-Chek Active Kit due to increased CP in RCC. RESULTS: In neonates, no modification of the biomarkers tested was detected. On the other hand, there was an increase in the levels of CP in the RCC of the 6-day-old ER. Interestingly, the concentration of blood glucose was decreased in this group. CONCLUSIONS: Our results indicate that there is no genotoxicity and oxidative stress in neonates and 6 days rats. However, the RCC had the highest concentration of CP that do not seem to be a consequence of oxidative stress. This study is the first to demonstrate the use of UHF-EMR causes different damage responses to proteins in the LCC and RCC.

Effect of 950 MHz UHF electromagnetic radiation on biomarkers of oxidative damage, metabolism of UFA and antioxidants in the livers of young rats of different ages.

PURPOSE: To assess the effect of 950 MHz ultra-high-frequency electromagnetic radiation (UHF EMR) on biomarkers of oxidative damage, as well as to verify the concentration of unsaturated fatty acids (UFA) and the expression of the catalase in the livers of rats of different ages. MATERIALS AND METHODS: Twelve rats were equally divided into two groups as controls (CR) and exposed (ER), for each age (0, 6, 15 and 30 days). Radiation exposure lasted half an hour per day for up to 51 days (21 days of gestation and 6, 15 or 30 days of life outside the womb). The specific absorption rate (SAR) ranged from 1.3-1.0 W/kg. The damage to lipids, proteins and DNA was verified by thiobarbituric acid reactive substances (TBARS), protein carbonyls and comets, respectively. UFA were determined by gas chromatography with a flame ionization detector. The expression of catalase was by Western blotting. RESULTS: The neonates had low levels of TBARS and concentrations of UFA after exposure. There was no age difference in the accumulation of protein carbonyls for any age. The DNA damage of ER 15 or 30 days was different. The exposed neonates exhibited lower expression of catalase. CONCLUSIONS: 950 MHz UHF EMR does not cause oxidative stress (OS), and it is not genotoxic to the livers of neonates or those of 6 and 15 day old rats, but it changes the concentrations of polyunsaturated fatty acid (PUFA) in neonates. For rats of 30 days, no OS, but it is genotoxic to the livers of ER to total body irradiation.

Selected oxidative stress markers in a South American crocodilian species.

Crocodilians and other diving vertebrates experience hypoperfusion and hypoxia of several internal organs during long dives. At the end of a dive, reperfusion of aerated blood may cause a physiologically relevant oxidative stress. In this study, we analyzed selected markers of oxidative stress in eight organs of normoxic Paraguayan caiman (Caiman yacare) captured in the Brazilian Pantanal wetlands during the winter of 2001 (six mature-adult males and eight young-adult males; AD-1 and YA-1 groups, respectively), and during the summer of 2002 (six young-adult males (YA-2 group), ten hatchlings and five embryos). Lipid peroxidation products determined by three different assays were generally highest in brain, liver and kidney (in comparison with all other organs), and lowest in white muscles from the tail and hind legs. Liver and kidney showed the highest levels of carbonyl protein, while brain showed low levels. Intermediate levels of oxidative stress markers were mostly found in the heart ventricles and lung. Differences in oxidative stress markers between AD-1 and YA-1 were organ-specific, showing no age-related correlation. However, most oxidative stress markers in YA-2 organs were either higher than (by 1.4- to 3.7-fold) or not significantly different from respective values in hatchlings organs. This pattern (hatchlings versus young-adults) was confirmed using correlation analysis of individual caiman size versus levels of oxidative damage markers in four organs. The higher level of oxidative stress markers in young-adults possibly relates to the fast growth rate (and thus, increased oxidative metabolic rate) of C. yacare in the first years of life. Differences in oxidative stress markers between YA-1 and YA-2 were also observed and were ascribed to seasonal changes in free radical metabolism. These results in normoxic C. yacare represent the first step towards understanding the age-related physiological oxidative stress of a diving reptile from a seasonally changing wetland environment.