Chromosome aberration dosimetry in cosmonauts after single or multiple space flights

Abstract

Background and aims: Cosmic radiation is one of the main hazards for manned space exploration. Uncertainty in radiation risk estimates for crews of long-term missions are very high, and direct biological measurements are necessary. We measured chromosomal aberrations in peripheral blood lymphocytes from 33 cosmonauts involved in space missions during the past 11 years. Methods: Blood lymphocytes from the cosmonauts were stimulated to grow in vitro and were harvested at their first mitosis. Slides were either stained with Giemsa stain for dicentrics analysis, or painted with whole-chromosome DNA probes for translocation analysis (FISH). Results: A statistically significant increase in the yield of chromosomal aberrations was measured following long-term space missions in lymphocytes from cosmonauts at their first flight. No significant changes in aberration frequencies were observed for short-term taxi flights. The increase in long-term missions was consistent with the values calculated from physical dosimetry data. However, for cosmonauts involved in two or more space flights, the yield of interchromosomal exchanges was not related to the total duration of space sojourn or integral absorbed dose. Indeed, the yield of aberrations at the end of the last mission was generally in the range of background frequencies measured before the first mission. Conclusions: Chromosome aberration dosimetry can detect radiation damage during space flight, and biological measurements support the current risk estimates for space radiation exposure. However, for cosmonauts involved in multiple space missions the frequency of chromosomal aberrations is lower than expected, suggesting that the effects of repeated space flights on this particular endpoint are not simply additive. Changes in the immune system in microgravity and/or adaptive response to space radiation may explain the apparent increase in radioresistance after multiple space flights.

Heavy ion carcinogenesis and human space exploration

“…Russian cosmonauts 57 show that the measured chromosomal rearrangements in crewmembers returning from space flight are consistent with current models, although the biological results are also affected by a large experimental uncertainty at low doses.…”

“…Besides, for cosmonauts involved in multiple spaceflights, the total yield of aberrations do not seem to be additive 51 , and in experienced cosmonauts with a total of about 2 years in the final yield of the aberrations is close to the measured background before the first flight 57 . The significance of these findings remains to be elucidated.…”

The influence of shielding on the biological effectiveness of accelerated particles for the induction of chromosome damage

“…It has been shown that the frequency of chromosome aberrations increases in astronauts blood lymphocytes after space flight (George et al, 2001 a and b;Federenko et al, 2001;Durante et al, 2003), and results indicate that biodosimetry estimates lie within the range expected from physical dosimetry and ICRP models, when samples are obtained shortly after flight .…”

X-Ray-Induced Radioresistance Against High-LET Radiations from Accelerated Neon-Ion Beams in Mice

“…In a recent study, a statistically significant increase in the yield of chromosomal aberrations in lymphocytes from cosmonauts at their first flight long-term space missions was observed. However, for cosmonauts involved in two or more space flights, the yield of aberrations at the end of the last mission was generally in the range of background frequencies measured before the first mission (Durante et al, 2003). This study suggests possible existence of AR induced by space irradiations in vivo.…”