Effects of low-dose ionizing radiation and menadione, an inducer of oxidative stress, alone and in combination in a vertebrate embryo model.
Radiat Res
; 178(5): 499-503, 2012 Nov.
Article
em En
| MEDLINE
| ID: mdl-23092554
ABSTRACT
Prior work has established the zebrafish embryo as an in vivo model for studying the biological effects of exposure to low doses of ionizing radiation. One of the known effects of radiation is to elevate the levels of reactive oxygen species (ROS) in tissue. However, ROS are also produced as by-products of normal metabolism and, regardless of origin, ROS produce similar chemical damage to DNA. Here we use the zebrafish embryo model to investigate whether the effects of low-dose (0-1.5 Gy) radiation and endogenous ROS are mechanistically distinct. We increased levels of endogenous ROS by exposure to low concentrations of the quinone drug, menadione. Imaging studies in live embryos showed that exposure to 3 µM or higher concentrations of menadione dramatically increased ROS levels. This treatment was associated with a growth delay and morphologic abnormalities, which were partially or fully reversible. By contrast, exposure to low doses of ionizing radiation had no discernable effects on overall growth or morphology, although, there was an increase in TUNEL-positive apoptotic cells, consistent with the results of prior studies. Further studies showed that the combined effect of radiation and menadione exposure are greater than with either agent alone, and that attenuation of the expression of Ku80, a gene important for repair of radiation-induced DNA damage, had only a slight effect on menadione sensitivity. Together, results suggest that ionizing radiation and menadione affect the embryo by distinct mechanisms.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Radiação Ionizante
/
Estresse Oxidativo
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Desenvolvimento Embrionário
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Morfogênese
Limite:
Animals
Idioma:
En
Revista:
Radiat Res
Ano de publicação:
2012
Tipo de documento:
Article
País de afiliação:
Estados Unidos