title: Adaptive responses induced by low dose radiation in dentate gyrus of rats.
abstract: The purpose of this study is to investigate the mechanism of alternative responses to low dose irradiation for neuronal cell proliferation in the dentate gyrus of rats. To determine the effect of a single exposure to radiation, rats were irradiated with a single dose of 0.1, 1, 10 or 20 Gy. To determine the effect of the cumulative dose, the animals were irradiated daily with 0.01 Gy or 0.1 Gy from 1 to 4 days. The neuronal cell proliferation was evaluated using immunohistochemistry for 5-bromo-2'-deoxyuridine (BrdU), Ki-67 and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) staining. Four consecutive daily irradiations with a 0.01 Gy/fraction increased the number of BrdU-positive and Ki-67-positive cells in a dose dependent manner, but this did not affect the number of TUNEL-positive cells. However, there was not a dose dependent relationship for the 0.1 Gy/fraction irradiation with the number of BrdU, Ki-67 and TUNEL positive cells. Our data support the explanation that the adaptive response, induced by low-dose radiation, in the hippocampus of rats is more likely a reflection of the perturbations of cell cycle progression.
authors.affiliation: Department of Radiation Oncology, Kyung Hee University Hospital, 1 Hoiki-Dong, Dongdaemun-Gu, Seoul, Korea. kangjino@khmc.or.kr
authors.forename: Jin Oh
authors.initials: JO
authors.lastname: Kang
authors.forename: Seong Eon
authors.initials: SE
authors.lastname: Hong
authors.forename: Sang Ki
authors.initials: SK
authors.lastname: Kim
authors.forename: Chang Ju
authors.initials: CJ
authors.lastname: Kim
authors.forename: Taeck Hyun
authors.initials: TH
authors.lastname: Lee
authors.forename: Hyun Kyung
authors.initials: HK
authors.lastname: Chang
authors.forename: Mal Soon
authors.initials: MS
authors.lastname: Shin
authors.forename: Hong
authors.initials: H
authors.lastname: Kim
mesh_terms: D000222:Adaptation, Physiological / Q000528:radiation effects; D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects*; D002470:Cell Survival / Q000528:radiation effects; D018891:Dentate Gyrus / Q000166:cytology* / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D008297:Male; D009473:Neuronal Plasticity / Q000528:radiation effects*; D009474:Neurons / Q000166:cytology* / Q000528:radiation effects*; D011829:Radiation Dosage; D051381:Rats; D017207:Rats, Sprague-Dawley