Effect of storage conditions of blood on radiation-induced chromosomal aberrations and apoptosis in human lymphocytes.

To evaluate the effect of storage conditions of blood on the direct relationship between radiation-induced chromosome aberrations and apoptosis in human peripheral blood lymphocytes, whole blood was irradiated with 3Gy X-rays. Directly after irradiation, a sample of blood was analyzed for chromosome damage and proliferation index, after phytohaemagglutinin stimulation and incubation at 37 degrees C for 56h. Blood samples were stored for 48h at 4 and 20 degrees C with or without phytohaemagglutinin and analyzed for cell viability and apoptosis at 0, 24 and 48h storage time. After 48h of storage, unstimulated cultures were stimulated to proliferate. These samples and cultures stimulated immediately before storage were incubated at 37 degrees C for 56h and analyzed for chromosome damage and proliferation index. Metaphases were examined for the presence of dicentrics, excess acentrics, and rings. Storage at 20 degrees C without phytohaemagglutinin for 48h increases significantly the yield of apoptosis and decreases significantly the yield of dicentrics. During 48h of storage time the presence of phytohaemagglutinin and the temperature of 4 degrees C protected the irradiated lymphocytes from apoptosis allowing accurate estimation of the real yield of radiation-induced chromosome damage. Therefore these blood-storage conditions enable analysis in metaphase and may offer some advantages for biodosimetry of absorbed radiation dose.