An early treatment with 17-ß-estradiol is neuroprotective against the long-term effects of neonatal ionizing radiation exposure

CACERES LG; URAN SL; ZORRILLA ZUBILETE MA; ROMERO JI; CAPANI F; GUELMAN LR

JOURNAL OF NEUROCHEMISTRY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2011 vol. 118 p. 626 - 635

0022-3042

Ionizing radiations can induce oxidative stress on target tissues,acting mainly through reactive oxygen species (ROS).The aim of this work was to investigate if 17-ß-estradiol (ßE)was able to prevent hippocampal-related behavioral and biochemicalchanges induced by neonatal ionizing radiationexposure and to elucidate a potential neuroprotective mechanism.Male Wistar rats were irradiated with 5 Gy of X-raysbetween 24 and 48 h after birth. A subset of rats was subcutaneouslyadministered with successive injections of bE or17-a-estradiol (aE), prior and after irradiation. Rats weresubjected to different behavioral tasks to evaluate habituationand associative memory as well as anxiety levels. HippocampalROS levels and protein kinase C (PKC) activity werealso assessed. Results show that although bE was unable toprevent radiation-induced hippocampal PKC activity changes,most behavioral abnormalities were reversed. Moreover, hippocampalROS levels in ßE-treated irradiated rats approachedcontrol values. In addition, aE administered to irradiated animalswas effective in preventing radiation-induced alterations.In conclusion, ßE was able to counteract behavioral and biochemicalchanges induced in irradiated animals, probablyacting through an antioxidant mechanism.