Analysis of spontaneous and bleomycin-induced chromosome damage in peripheral lymphocytes of long-haul aircrew members from Argentina.

Spontaneous and bleomycin (BLM)-induced chromosomal aberrations in G0 and G2 stages of the cell cycle have been analyzed in peripheral lymphocytes of 21 long-haul aircrew members from Argentina in order to assess BLM-induced clastogenesis as a first approach to determine the DNA repair capacity and thereby the susceptibility to environmental cancers in aircrew. The possibility that occupational exposure of flight personnel to cosmic radiation can induce an adaptive response in their peripheral lymphocytes that can be detected by a subsequent in vitro treatment with BLM was also investigated. For comparison, aberrations were also scored in the lymphocytes of 15 healthy volunteers matched by age, health, sex, drinking and smoking habits to the flight personnel group. Aircrew exhibited a higher frequency of spontaneous dicentrics and ring chromosomes than the control population (p<0.05). BLM sensitivity test showed that aircrew and controls are equally sensitive to BLM G2 clastogenic effects, since both groups exhibited a similar frequency of chromatid breaks per cell (p>0.05). However, the aircrew sampled population was almost two times more sensitive to BLM G0 clastogenic effects than controls (p<0.05). Therefore, our data suggest that chronic exposure of aircrew to cosmic radiation increases the in vitro chromosomal sensitivity of their peripheral lymphocytes to BLM (at least in the G0 stage of the cell cycle), and that occupational exposure of flight personnel to cosmic radiation does not induce an adaptive response to this radiomimetic compound. Our results justify further studies aimed at determine if those aircrew members hypersensitive to BLM are more prone to develop environmental cancer than BLM-insensitive individuals.