title: The release of bystander factor(s) from tissue explant cultures of rainbow trout (Onchorhynchus mykiss) after exposure to gamma radiation.
abstract: The bystander response has been documented in cell lines and cell cultures derived from aquatic species over the past several years. However, little work has been undertaken to identify a similar bystander response in tissue explant cultures from fish. In this study, indirect effects of ionizing gamma radiation on tissue explant cultures of fish were investigated. Tissue explants in culture were exposed to 0.5 Gy and 5 Gy gamma radiation from a 60Co teletherapy unit. A bystander response in Epithelioma papulosum cyprini (EPC) cells exposed to gamma-irradiated tissue conditioned medium from rainbow trout explants was investigated, and the effects on cell survival were quantified by the clonogenic survival assay. Dichlorofluorescein and rhodamine 123 fluorescent dyes were used to identify alterations in reactive oxygen species (ROS) and mitochondrial membrane potential (MMP), respectively. Results indicate a different response for the three tissue types investigated. Clonogenic assay results vary from a decrease in cell survival (gill) to no effect (skin) to a stimulatory effect (spleen). Results from fluorescence assays of ROS and MMP show similarities to clonogenic assay results. This study identifies a useful model for further studies relating to the bystander effect in aquatic organisms in vivo and ex vivo.
authors.affiliation: Radiation and Environmental Science Centre, Focas Institute, Dublin Institute of Technology, Dublin 8, Ireland. colm.odowd@dit.ie
authors.forename: Colm
authors.initials: C
authors.lastname: O'Dowd
authors.forename: Carmel E
authors.initials: CE
authors.lastname: Mothersill
authors.forename: Michael T
authors.initials: MT
authors.lastname: Cairns
authors.forename: Brian
authors.initials: B
authors.lastname: Austin
authors.forename: Brendan
authors.initials: B
authors.lastname: McClean
authors.forename: Fiona M
authors.initials: FM
authors.lastname: Lyng
authors.forename: James E J
authors.initials: JE
authors.lastname: Murphy
mesh_terms: D000818:Animals; D024201:Bystander Effect / Q000502:physiology* / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D004781:Environmental Exposure; D005720:Gamma Rays; D008564:Membrane Potentials / Q000502:physiology / Q000528:radiation effects; D051336:Mitochondrial Membranes / Q000502:physiology / Q000528:radiation effects*; D017686:Oncorhynchus mykiss / Q000502:physiology*; D009928:Organ Specificity; D011829:Radiation Dosage; D017382:Reactive Oxygen Species / Q000378:metabolism*; D046509:Tissue Culture Techniques
chemical_list: D017382:Reactive Oxygen Species