HIPPOCAMPAL-RELATED MEMORY DEFICITS AND HISTOLOGICAL DAMAGE INDUCED BY NEONATAL IONIZING RADIATION EXPOSURE. ROLE OF OXIDATIVE STATUS

CACERES, LUCILA GUADALUPE; AON BERTOLINO, LAURA; SARACENO, GUSTAVO EZEQUIEL; ZORRILLA ZUBILETE, MARÍA AURELIA; URAN, SOLEDAD LUCÍA; CAPANI, FRANCISCO; GUELMAN, LAURA RUTH

BRAIN RESEARCH

ELSEVIER SCIENCE BV

Año: 2010 vol. 1312 p. 67 - 78

0006-8993

Ionizing radiations induce oxidative stress on target tissues, mainly through thegeneration of reactive oxygen species (ROS). However, there are few data available onthe behavioral effects of moderate doses of ionizing radiation. The aim of the present workwas to evaluate the performance of adult rats irradiated at birth in different hippocampaldependentbehavioral tasks and to establish a relationship with the oxidative status andhistological changes in rat hippocampus (Hip). Male Wistar rats were irradiated with 5 Gyof X rays between 24 and 48 h after birth. Thirty days later, rats were subjected to openfield, object recognition and inhibitory avoidance tasks. In addition, oxidative statusmarkers as well as protein kinase C (PKC) activity and histological changes were assessedin control and irradiated Hip. Results show an impairment in recognition and habituationmemories in 30-day-old animals exposed to neonatal ionizing radiation, both at short- (ST)and at long-term (LT), whereas an improvement in associative memory was observed atST. In addition, histological alterations were observed in irradiated Hip. Although anincrease in ROS levels and PKC activity were found in irradiated Hip, no changes in theantioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) were observed.Taken together, our results support the hypothesis that an increased PKC activity, inducedby neonatal ionizing radiation on rat Hip, could play a role in the generation of animbalance between ROS levels and antioxidant systems and might underlie radiationinducedhippocampal histological damage as well as the Hip-dependent behavioralchanges found in irradiated rats.