ZFIN ID: ZDB-PUB-070726-24
Quantification of ionizing radiation-induced cell death in situ in a vertebrate embryo
Bladen, C.L., Flowers, M.A., Miyake, K., Podolsky, R.H., Barrett, J.T., Kozlowski, D.J., and Dynan, W.S.
Date: 2007
Source: Radiation Research   168(2): 149-157 (Journal)
Registered Authors: Kozlowski, David J.
Keywords: none
MeSH Terms:
  • Animals
  • Apoptosis/radiation effects*
  • Dose-Response Relationship, Radiation
  • Embryo, Nonmammalian/radiation effects*
  • In Situ Nick-End Labeling
  • Radiation Tolerance
  • Zebrafish
PubMed: 17638406 Full text @ Radiat. Res.
Quantitative studies of radiation cytotoxicity have been performed mostly in cells in culture. For a variety of reasons, however, the response of cells in culture may not reflect the response for cells in situ in a whole organism. We describe here an approach for quantification of radiation-induced cell death in vivo using the transparent embryo of the zebrafish, Danio rerio, as a model vertebrate system. Using this system, we show that the number of TUNEL-positive cells within a defined region increases approximately linearly with radiation dose up to 1 Gy. The results are consistent with predictions of a linear-quadratic model. The use of alternative models, accommodating a response threshold or low-dose hypersensitivity, did not significantly improve the fit to the observed data. Attenuation of the expression of the 80-kDa subunit of Ku, an essential protein for the nonhomologous end-joining pathway of repair, led to a dose reduction of 30- to 34-fold, possibly approaching the limit where each double-strand break causes a lethal hit. In both the Ku80-attenuated and the control embryos, apoptotic cells were distributed uniformly, consistent with a cell-autonomous mechanism of cell death. Together, these results illustrate the potential of the zebrafish for quantitative studies of radiation-induced cell death during embryogenesis and in vivo.