Volume 43, Number 5, 200836th annual meeting of the European Radiation Research Society
|Number of page(s)||1|
|Section||Poster Presentation - Radiotoxicology and contamination of Biota|
|Published online||03 September 2008|
Chronic ingestion of 137-caesium does not induce significant modifications of the immune system
IRSN, DRPH/SRBE, LRTOX, BP n°17, 92262 Fontenay aux roses, France
2 IRSN/DRPH/SRBE/LRTOX, Site du Tricastin, Bat 53 bp166, 26702 Pierrelatte cedex, France, Metropolitan
3 IRSN, Direction scientifique, Centre d'études de Cadarache, Bt 229, BP n°3, 13115 St Paul lez Durance cedex, France
Twenty years after the Chernobyl accident, 137-Caesium (137-Cs) is the main residual radionuclide found in contaminated areas. 137-Cs progressively integrated food chains until man, inducing a chronic contamination of large populations through daily ingestion of small quantities of 137-Cs. Some studies indicated an accumulation of 137-Cs in the thyroid, the heart and muscles. It was then suggested that 137-Cs contamination could lead to some pathologies observed within populations living onto contaminated areas. In order to determine the possible influence of Cs137 onto the immune system, we developed a mouse model of chronic contamination through drinking water with a concentration of 20 KBq.l-1 of 137-Cs. This corresponds to a daily ingestion of 6 KBq.day-1.kg of body weight, ten times higher than the highest measurements made after the Chernobyl accident. Parent animals were contaminated before mating and during gestation. After weaning, contamination of offspring was continued through drinking water. Gamma counts indicated that 137-Cs was found in all tissue tested at a concentration between 2 and 20 Bq/g of tissue. However, a progressive accumulation of 137-Cs was observed in muscles and kidney, and to a lesser extend in the heart and in femurs, mainly until 9 weeks of age. The immune system was evaluated by several means, including phenotypic and functional analyses. Phenotypic analysis of blood cells did not showed significant changes in both CD4+ and CD8+ T lymphocytes, in CD4+CD25+ Tregs, or in B220+ B lymphocytes between control and 137-Cs contaminated animals. Intrathymic differentiation was evaluated by phenotypic analysis of thymocyte subpopulation and by T cell excision circle (Trec) detection. However, no significant changes in intra-thymic differentiation were observed whatever the age of animals. Three functional tests were also used to evaluate the immune system, response of splenocytes to a mitogenic stimulation, response of splenocytes in a mixed lymphocyte reaction test, and specific response to a vaccination against tetanus toxoid. However, no significant changes were observed in 137-Cs contaminated animals as compared to control animals, even in 35 weeks-old animals. Overall, these results suggest that 137-Cs may accumulate over time in some organs such as the heart, the kidney, the femurs and muscles. However, our results also demonstrate that 137-Cs ingestion does not induce a significant modification of the immune system. This suggests that the pathologies associated with the immune system observed within populations living onto contaminated territories might not be attributed solely to the 137-Cs internal contamination.
Key words: Immune system / toxicology / 137-caesium
© EDP Sciences, 2008
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.