title: Adaptive response of low linear energy transfer X-rays for protection against high linear energy transfer accelerated heavy ion-induced teratogenesis.
abstract: BACKGROUND
  Adaptive response (AR) of low linear energy transfer (LET) irradiations for protection against teratogenesis induced by high LET irradiations is not well documented. In this study, induction of AR by X-rays against teratogenesis induced by accelerated heavy ions was examined in fetal mice.
  
  
  METHODS
  Irradiations of pregnant C57BL/6J mice were performed by delivering a priming low dose from X-rays at 0.05 or 0.30 Gy on gestation day 11 followed one day later by a challenge high dose from either X-rays or accelerated heavy ions. Monoenergetic beams of carbon, neon, silicon, and iron with the LET values of about 15, 30, 55, and 200 keV/μm, respectively, were examined. Significant suppression of teratogenic effects (fetal death, malformation of live fetuses, or low body weight) was used as the endpoint for judgment of a successful AR induction.
  
  
  RESULTS
  Existence of AR induced by low-LET X-rays against teratogenic effect induced by high-LET accelerated heavy ions was demonstrated. The priming low dose of X-rays significantly reduced the occurrence of prenatal fetal death, malformation, and/or low body weight induced by the challenge high dose from either X-rays or accelerated heavy ions of carbon, neon or silicon but not iron particles.
  
  
  CONCLUSIONS
  Successful AR induction appears to be a radiation quality event, depending on the LET value and/or the particle species of the challenge irradiations. These findings would provide a new insight into the study on radiation-induced AR in utero.
authors.affiliation: Radiation Risk Reduction Research Program, Research Center for Radiation Protection, National Institute of Radiological Sciences, Chiba, Japan. jp2813km@nits.go.jp
authors.forename: Bing
authors.initials: B
authors.lastname: Wang
authors.forename: Yasuharu
authors.initials: Y
authors.lastname: Ninomiya
authors.forename: Kaoru
authors.initials: K
authors.lastname: Tanaka
authors.forename: Kouichi
authors.initials: K
authors.lastname: Maruyama
authors.forename: Guillaume
authors.initials: G
authors.lastname: Varès
authors.forename: Kiyomi
authors.initials: K
authors.lastname: Eguchi-Kasai
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Nenoi
mesh_terms: D000016:Abnormalities, Radiation-Induced / Q000209:etiology*; D000222:Adaptation, Physiological / Q000528:radiation effects*; D000818:Animals; D002244:Carbon / Q000009:adverse effects; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005313:Fetal Death; D047109:Fetal Development / Q000528:radiation effects; D020567:Fetal Weight / Q000528:radiation effects; D005333:Fetus / Q000528:radiation effects; D020450:Heavy Ions / Q000009:adverse effects*; D007501:Iron / Q000009:adverse effects; D018499:Linear Energy Transfer; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009356:Neon / Q000009:adverse effects; D011247:Pregnancy; D011836:Radiation Tolerance / Q000502:physiology / Q000528:radiation effects*; D011839:Radiation, Ionizing; D012825:Silicon / Q000009:adverse effects; D014965:X-Rays
chemical_list: D009356:Neon; D002244:Carbon; D007501:Iron; D012825:Silicon