Abstract
In the past decade, it has been reported that the non-irradiated cells which are close to the irradiated cells respond indirectly to radiation. This phenomenon is so called radiation-induced bystander effect. We would report new findings about high- or low-LET radiation adaptive response induced through radiation-induced bystander effects mediated by nitric oxide (NO).
1. Induction of adaptive response by low-dose X-irradiation: At 3 to 12 hr after low-dose irradiation at 0.02 Gy, adaptive response was obviously observed in p53-deficient human non-small lung cancer H1299 cells transfected with wild-type p53 gene. This response was partially diminished by the addition of carboxy-PTIO.
2. Induction of adaptive response by low-dose Carbon-beam (290 MeV/u, 70 keV/μm) irradiation: At 3 to 24 hr after low-dose irradiation at 0.02 Gy, adaptive response was obviously observed. This response was partially diminished by the addition of carboxy-PTIO.
We found that radiation adaptive response was induced by not only low-LET but also high-LET radiation and that these responses were induced through NO production. It is suggested that radiation-induced bystander effects mediated NO may contributes to the induction of these responses.
