spio-annexin v, a potential probe for mri detection of radiation induced apoptosis

background: finding a suitable method for rapid, accurate and reliable estimation of absorbed dose has high priority in management of the radiation exposed persons. shortly after radiation exposure, apoptosis is a major detriment in proliferative tissues such as the hematopoietic system. therefore, quantification of apoptosis in these tissues could be useful for rapid estimation of radiation exposure. annexin v (anx) is considered as a biological probe for detection of apoptotic cells. the aim of the present study is to investigate the potential suitability of apoptosis quantification for estimation of radiation exposure. materials and methods: in order to determine the biological distribution of anx within the mice body after radiation exposure, mice whole body irradiated with 2, 4, 6 and 8 gy (60co gamma rays). ten hours later, anx conjugated with super paramagnetic iron oxide nanoparticles (spio-anx) was administered intravenously and magnetic resonance imaging was conducted 3 hours later. results: average signal intensities in the regions of interest (rois) of the femur bone marrow, liver and testis were calculated and normalized to parafemoral muscle signals. spio-anx accumulated in bone marrow of irradiated groups and significantly decreased the normalized mean of signal intensity for bone marrow in comparison with control group (p< 0.01). conclusion: tracing and quantification of spio-anx in bone marrow can be used as an indicator for radiation exposure. however, development and optimization of the assay are necessary for discrimination between different radiation doses.