title: Effects of shielding on the induction of 53BP1 foci and micronuclei after Fe ion exposures.
abstract: High atomic number and high-energy (HZE) particles in deep space are of low abundance but substantially contribute to the biological effects of space radiation. Shielding is so far the most effective way to partially protect astronauts from these highly penetrating particles. However, simulated calculations and measurements have predicted that secondary particles resulting from the shielding of cosmic rays produce a significant fraction of the total dose and dose equivalent. In this study, we investigated the biological effects of secondary radiation with two cell types, and with cells exposed in different phases of the cell cycle, by comparing the biological effects of a 200 MeV/u iron beam with a shielded beam in which the energy of the iron ion beam was decreased from 500 MeV/u to 200 MeV/u with PMMA, polyethylene (PE), or aluminum. We found that beam shielding resulted in increased induction of 53BP1 foci and micronuclei in a cell-type-dependent manner compared with the unshielded 200 MeV/u Fe ion beam. These findings provide experimental proof that the biological effects of secondary particles resulting from the interaction between HZE particles and shielding materials should be considered in shielding design.
authors.affiliation: Department of Space Radiobiology, Key Laboratory of Heavy Ion Radiation Biology and Medicine, Institute of Modern Physics, Chinese Academy of Sciences, 509 Nanchang Road, Lanzhou 730000, China.
authors.forename: Wentao
authors.initials: W
authors.lastname: Hu
authors.forename: Hailong
authors.initials: H
authors.lastname: Pei
authors.forename: He
authors.initials: H
authors.lastname: Li
authors.forename: Nan
authors.initials: N
authors.lastname: Ding
authors.forename: Jinpeng
authors.initials: J
authors.lastname: He
authors.forename: Jufang
authors.initials: J
authors.lastname: Wang
authors.forename: Yoshiya
authors.initials: Y
authors.lastname: Furusawa
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Hirayama
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Matsumoto
authors.forename: Cuihua
authors.initials: C
authors.lastname: Liu
authors.forename: Yinghui
authors.initials: Y
authors.lastname: Li
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Kawata
authors.forename: Guangming
authors.initials: G
authors.lastname: Zhou
mesh_terms: D002453:Cell Cycle / Q000235:genetics / Q000528:radiation effects*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000235:genetics / Q000528:radiation effects*; D003359:Cosmic Radiation; D004249:DNA Damage / Q000235:genetics*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D020450:Heavy Ions; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics*; D007504:Iron Radioisotopes; D018499:Linear Energy Transfer / Q000528:radiation effects; D048629:Micronuclei, Chromosome-Defective / Q000187:drug effects*; D011835:Radiation Protection / Q000295:instrumentation*; D012542:Scattering, Radiation; D000071857:Tumor Suppressor p53-Binding Protein 1
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D007504:Iron Radioisotopes; C498301:TP53BP1 protein, human; D000071857:Tumor Suppressor p53-Binding Protein 1
keywords: DNA damage; secondary particles; shielding; space radiation; survival