PMID- 21770703
OWN - NLM
STAT- MEDLINE
DCOM- 20111021
LR  - 20231104
IS  - 1362-3095 (Electronic)
IS  - 0955-3002 (Print)
IS  - 0955-3002 (Linking)
VI  - 87
IP  - 9
DP  - 2011 Sep
TI  - Neurocytotoxic effects of iron-ions on the developing brain measured in vivo 
      using medaka (Oryzias latipes), a vertebrate model.
PG  - 915-22
LID - 10.3109/09553002.2011.584944 [doi]
AB  - PURPOSE: Exposure to heavy-ion radiation is considered a critical health risk on 
      long-term space missions. The developing central nervous system (CNS) is a highly 
      radiosensitive tissue; however, the biological effects of heavy-ion radiation, 
      which are greater than those of low-linear energy transfer (LET) radiation, are 
      not well studied, especially in vivo in intact organisms. Here, we examined the 
      effects of iron-ions on the developing CNS using vertebrate organism, fish 
      embryos of medaka (Oryzias latipes). MATERIALS AND METHODS: Medaka embryos at 
      developmental stage 28 were irradiated with iron-ions at various doses of 0-1.5 
      Gy. At 24 h after irradiation, radiation-induced apoptosis was examined using an 
      acridine orange (AO) assay and histologically. To estimate the relative 
      biological effectiveness (RBE), we quantified only characteristic AO-stained 
      rosette-shaped apoptosis in the developing optic tectum (OT). At the time of 
      hatching, morphological abnormalities in the irradiated brain were examined 
      histologically. RESULTS: The dose-response curve utilizing an apoptotic index for 
      the iron-ion irradiated embryos was much steeper than that for X-ray irradiated 
      embryos, with RBE values of 3.7-4.2. Histological examinations of irradiated 
      medaka brain at 24 h after irradiation showed AO-positive rosette-shaped clusters 
      as aggregates of condensed nuclei, exhibiting a circular hole, mainly in the 
      marginal area of the OT and in the retina. However, all of the irradiated embryos 
      hatched normally without apparent histological abnormalities in their brains. 
      CONCLUSION: Our present study indicates that the medaka embryo is a useful model 
      for evaluating neurocytotoxic effects on the developing CNS induced by exposure 
      to heavy iron-ions relevant to the aerospace radiation environment.
FAU - Yasuda, Takako
AU  - Yasuda T
AD  - Department of Integrated Biosciences, Graduate School of Frontier Sciences, the 
      University of Tokyo, Kashiwa, Chiba. t_yasuda@ib.k.u-tokyo.ac.jp
FAU - Oda, Shoji
AU  - Oda S
FAU - Yasuda, Hiroshi
AU  - Yasuda H
FAU - Hibi, Yusuke
AU  - Hibi Y
FAU - Anzai, Kazunori
AU  - Anzai K
FAU - Mitani, Hiroshi
AU  - Mitani H
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20110719
PL  - England
TA  - Int J Radiat Biol
JT  - International journal of radiation biology
JID - 8809243
RN  - 0 (Cytotoxins)
RN  - E1UOL152H7 (Iron)
SB  - IM
MH  - Animals
MH  - Apoptosis/radiation effects
MH  - Brain/cytology/*embryology/*radiation effects
MH  - Cytotoxins/*toxicity
MH  - Embryo, Nonmammalian/*radiation effects
MH  - Heavy Ions/*adverse effects
MH  - Iron/*toxicity
MH  - Models, Animal
MH  - Oryzias/*embryology
MH  - Relative Biological Effectiveness
PMC - PMC3169016
EDAT- 2011/07/21 06:00
MHDA- 2011/10/22 06:00
CRDT- 2011/07/21 06:00
PHST- 2011/07/21 06:00 [entrez]
PHST- 2011/07/21 06:00 [pubmed]
PHST- 2011/10/22 06:00 [medline]
AID - 10.3109/09553002.2011.584944 [doi]
PST - ppublish
SO  - Int J Radiat Biol. 2011 Sep;87(9):915-22. doi: 10.3109/09553002.2011.584944. Epub 
      2011 Jul 19.