Effects of whole body radiotherapy on lipid peroxidation and antioxidant system parameters of brain tissues in different aged groups of rats

Exposure of ionizing radiation that is used in radiotherapy caused the production of free radicals and oxidative stress depending on dose and the time of irradiation in organism. Oxidative stress produced by reactive oxygen species have been thought to be effective on the pathogenesis of cardiovascular diseases, neurodegenerative disorders, aging and cancer. This study aims to find out the age-related changes of lipid peroxidation and antioxidant system parametres levels produced by radiotherapy that is widely used on cancer treatment and their connection between each other. In this study, thirty-five male Wistar albino rats (ages between 1, 4, 12 weeks (n=10) and 1 year (n=5)) were divided into four groups. For the rats in all groups irradiation were performed on a Cobalt-60 unit using a single fraction of 8 Gy. The brain tissues of the rats were homogenized in PBS solution. The homogenate was divided into two portions. One portion of the homogenate was used for the measurement of the MDA. The other portion of homogenate was centrifuged. The supernatant was seperated and used for the measurement of the SOD, CAT, GSHPx and Lowry protein analyze. The SOD activity decreased significantly in 1 week old rats. Decreased activities were also seen in the other groups, but it was insignificant (p<0,05). The decrease in GSHPx and CAT activities was more obvious in 1 week and 1 year old rats than others. No change in enzyme activities of 4 and 12 weeks old rats was found to be significant (p<0,05). The MDA levels of all groups increased. The highest MDA levels were seen in 1 year old rats (p<0,05). Finally, ionizing radiation used radiotherapy have effected antioxidant systems and increased MDA levels of the tissue. These changes were more in the 1 week and 1 year old rats than others. According to the results of the present study, many systems of newborn rats don?t run properly and the 1 year old age rats have the loss of physiological capacities. Key Words: Radiotherapy, Free radicals, Aging, Antioxidant systems, Lipid peroxidation.