title: A quantitative study of radiation-induced apoptosis in two rat yolk sac tumour cell lines with different radiosensitivities in vitro.
abstract: Two rat yolk sac tumour cell lines with different radiosensitivities were used to quantify the extent of apoptosis following irradiation by using a DNA fragmentation assay in vitro. Apoptosis was also confirmed by fluorescence analysis of nuclear morphological changes by using Hoechst 33258. A radiosensitive cell line, NMT-1 cells, showed morphological changes characteristic of apoptosis by fluorescence microscopic observation at 24 hours after irradiation with a single dose of 10 Gy. Development of apoptosis in NMT-1 cells was observed as a function of time within 24 hours after irradiation. There was a significant increase in the amount of apoptosis between 2 and 5 Gy only in NMT-1 cells but increasing the radiation dose from 5 Gy to 10 Gy did not result in increased apoptosis. A radioresistant NMT-1R cells, on the other hand, displayed a small apoptotic response to an irradiation dose of 10 Gy at 24 hours after irradiation.
authors.affiliation: Department of Radiology and Radiation Oncology, Gunma University School of Medicine, Japan. nmihashi@sb.gunma-u.ac.jp
authors.forename: N
authors.initials: N
authors.lastname: Mitsuhashi
authors.forename: H
authors.initials: H
authors.lastname: Ishikawa
authors.forename: Y
authors.initials: Y
authors.lastname: Saito
authors.forename: T
authors.initials: T
authors.lastname: Takahashi
authors.forename: H
authors.initials: H
authors.lastname: Sakurai
authors.forename: M
authors.initials: M
authors.lastname: Nozaki
authors.forename: T
authors.initials: T
authors.lastname: Akimoto
authors.forename: M
authors.initials: M
authors.lastname: Hasegawa
authors.forename: K
authors.initials: K
authors.lastname: Maebayashi
authors.forename: H
authors.initials: H
authors.lastname: Niibe
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000528:radiation effects*; D002453:Cell Cycle / Q000528:radiation effects; D002467:Cell Nucleus / Q000648:ultrastructure; D053938:DNA Fragmentation; D004307:Dose-Response Relationship, Radiation; D018240:Endodermal Sinus Tumor / Q000532:radiotherapy*; D008856:Microscopy, Fluorescence; D051381:Rats; D013997:Time Factors; D014407:Tumor Cells, Cultured