Leukocyte apoptosis and micronuclei induction in individuals with varying sensitivity to ionising radiation

Abstract

The identification of radiosensitive individuals using test doses of radiation in vitro of blood samples allows one to manage the detri- ment of exposure to ionising radiation of members of the public and radiation workers. Current methodologies allow one to quan- tify radiation-induced apoptosis in lymphocytes (Leukocyte Apoptotic Assay – LAA), an endpoint controlled by molecular pathways as well as micronuclei induction, a cytogenetic type of measurement. In this study, blood from 10 donors was used to analyse radiation-induced apoptosis and micronuclei formations in each instance. Micronuclei formations in isolated lymphocytes were numerated in binucleated cells 72 hours after in vitro radiation exposure and leukocyte apoptosis was measured at 48 hours after in vitro radiation exposure. Variation in response for different individuals was noted and compared using both endpoints. However, no significant relationship could be established between the level of apoptosis and micronuclei frequency induced by a test dose of 2Gy of 6MV X-rays. The fundamental differences in these two endpoints, molecular and cytogenetic respectively, may be a possible reason for this. It is concluded that the measure of radiosensitivity of different individuals is dependent on the endpoint in question.