title: An early treatment with 17-β-estradiol is neuroprotective against the long-term effects of neonatal ionizing radiation exposure.
abstract: 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-β-estradiol (βE) was able to prevent hippocampal-related behavioral and biochemical changes induced by neonatal ionizing radiation exposure and to elucidate a potential neuroprotective mechanism. Male Wistar rats were irradiated with 5 Gy of X-rays between 24 and 48 h after birth. A subset of rats was subcutaneously administered with successive injections of βE or 17-α-estradiol (αE), prior and after irradiation. Rats were subjected to different behavioral tasks to evaluate habituation and associative memory as well as anxiety levels. Hippocampal ROS levels and protein kinase C (PKC) activity were also assessed. Results show that although βE was unable to prevent radiation-induced hippocampal PKC activity changes, most behavioral abnormalities were reversed. Moreover, hippocampal ROS levels in βE-treated irradiated rats approached control values. In addition, αE administered to irradiated animals was effective in preventing radiation-induced alterations. In conclusion, βE was able to counteract behavioral and biochemical changes induced in irradiated animals, probably acting through an antioxidant mechanism.
authors.affiliation: 1ª Cátedra de Farmacología, Facultad de Medicina, UBA, CEFYBO-CONICET, Buenos Aires, Argentina.
authors.forename: Lucila G
authors.initials: LG
authors.lastname: Caceres
authors.forename: Soledad L
authors.initials: SL
authors.lastname: Uran
authors.forename: María A
authors.initials: MA
authors.lastname: Zorrilla Zubilete
authors.forename: Juan I
authors.initials: JI
authors.lastname: Romero
authors.forename: Francisco
authors.initials: F
authors.lastname: Capani
authors.forename: Laura R
authors.initials: LR
authors.lastname: Guelman
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D000975:Antioxidants / Q000378:metabolism; D001007:Anxiety / Q000523:psychology; D001362:Avoidance Learning / Q000187:drug effects / Q000528:radiation effects; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D006185:Habituation, Psychophysiologic / Q000187:drug effects / Q000528:radiation effects; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D008297:Male; D008568:Memory / Q000187:drug effects; D009043:Motor Activity / Q000187:drug effects / Q000528:radiation effects; D018696:Neuroprotective Agents; D011247:Pregnancy; D011493:Protein Kinase C / Q000378:metabolism; D011833:Radiation Injuries, Experimental / Q000517:prevention & control; D011837:Radiation-Protective Agents; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism / Q000528:radiation effects; D013995:Time; D014965:X-Rays
chemical_list: D000975:Antioxidants; D018696:Neuroprotective Agents; D011837:Radiation-Protective Agents; D017382:Reactive Oxygen Species; D004958:Estradiol; D011493:Protein Kinase C