Modification of 10 cGy neutron or gamma-rays induced chromosomal damages by hyperthermia: an in vitro study

To evaluate the effects of hyperthermia (HT) on the frequency of chromosomal aberrations induced by a low dose of neutron or γ-rays in human peripheral blood lymphocytes. Blood samples were exposed to HT (41.5°C for 30 and 60min, 43°C for 15 and 30min), 10 cGy neutron or γ-rays, HT + neutron/γ, and neutron/γ + HT. After standard cell culture, harvesting, fixation and staining, the chromosomal damages were scored in metaphase plates. HT alone at 41.5°C did not induce chromatid or chromosome aberrations, however, the frequency of damages was significantly higher at 43°C (P<0.05). Furthermore, the chromosomal damages was significantly different when cells were irradiated with neutron or γ-rays alone (P<0.01). HT 1 hr post neutron/γ irradiation significantly induced higher chromosome damages in comparison to HT 1 hr before irradiation (P<0.05). The chromosomal damages were remarkably higher when cells were irradiated with neutron then heated at 43°C for 30 min. Since increasing frequency of chromosome damages increases probability of cell death, application of HT after neutron irradiation (instead of X– or γ- rays) might be considered as a procedure for cells killing in radiotherapy.