Effect of low doses of ionizing radiation on cells cultured from the hematopoietic tissue of the Dublin Bay prawn, Nephrops norvegicus

Explant cultures from the hematopoietic tissue of the Dublin Bay prawn, Nep hrops norvegicus, were exposed to low doses of Co-60 gamma radiation. Cells growing from the explants were examined gamma days after irradiation using light and transmission electron microscopy and were also tested for their ability to produce signals indicative of a bystander effect. The exposed cu ltures displayed pronounced damage and were orders of magnitude more sensit ive than the data in the literature would suggest for arthropod cells. The cultures were also more sensitive than mammalian cells that were exposed to similar doses. Cellular abnormalities included damage to cytoplasmic organ elles, particularly the cytoskeleton. Abnormal mitochondria were also promi nent. At low doses (0.5 Gy), nuclear damage was not apparent in the culture s, but there was evidence of a dose-dependent increase in apoptosis. The ir radiated cultures released a factor into the medium that was capable of ind ucing apoptosis and cell death in unirradiated fish and human cells. This b ystander effect was of a similar magnitude to that reported for mammalian c ell systems. It is suggested that these crustaceans may be highly sensitive to radiation, unlike terrestrial arthropods and certain other invertebrate s, which are generally considered to be radioresistant. (C) 2001 by Radiati on Research Society.