title: Prenatal ionizing radiation-induced apoptosis of the developing murine brain with special references to the expression of some proteins.
abstract: Apoptosis induced by ionizing irradiation of the developing mouse brain was investigated by using histology, analysis of DNA fragmentation on agarose gel and electron microscopy. A TUNEL-labeled index (L.I.) was calculated from the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling (TUNEL) assay in 4 specific regions, cortical plate, intermediate zone, subependymal zone, and subependymal germinal matrix. The kinetics of apoptosis associated protein was examined by western blotting and immunofluorescence. C57BL/6J mice pregnant on embryonic day 14 (E14) were exposed to a single dose of 1.5-Gy irradiation. Irradiated fetal brains at E15 and E17 showed extensive apoptosis with morphological characteristics. In all 4 regions, L.I. was greater in irradiated brains than in control brains at E15 and E17. Most of TUNEL-labeled cells expressed a mature neuronal marker (NeuN) and Bax protein, which is up-regulated in irradiation-induced apoptosis. Ionizing radiation moderately enhanced expression of Bax, Bcl-xL, and Cpp32 proteins. Postnatal irradiated mice showed microencephaly as compared to age-matched mice and the weight of whole body including brain decreased moderately.
authors.affiliation: First Division, Department of Pathology, Kobe University School of Medicine.
authors.forename: M
authors.initials: M
authors.lastname: Kitamura
authors.forename: K
authors.initials: K
authors.lastname: Itoh
authors.forename: A
authors.initials: A
authors.lastname: Matsumoto
authors.forename: Y
authors.initials: Y
authors.lastname: Hayashi
authors.forename: R
authors.initials: R
authors.lastname: Sasaki
authors.forename: Y
authors.initials: Y
authors.lastname: Imai
authors.forename: H
authors.initials: H
authors.lastname: Itoh
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000528:radiation effects*; D015153:Blotting, Western; D001921:Brain / Q000196:embryology* / Q000528:radiation effects* / Q000648:ultrastructure; D053148:Caspase 3; D020169:Caspases / Q000032:analysis / Q000235:genetics; D053938:DNA Fragmentation; D005260:Female; D005455:Fluorescent Antibody Technique; D015870:Gene Expression / Q000528:radiation effects*; D005865:Gestational Age; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D066298:In Vitro Techniques; D007700:Kinetics; D051379:Mice; D008810:Mice, Inbred C57BL; D008831:Microcephaly / Q000209:etiology; D008854:Microscopy, Electron; D009929:Organ Size; D011247:Pregnancy; D011518:Proto-Oncogene Proteins / Q000032:analysis / Q000235:genetics; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis / Q000235:genetics; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein
chemical_list: C494827:Bax protein, mouse; C494812:Bcl2l1 protein, mouse; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein; C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases