Highlight | Nuclear Toxicology
Under the Environmental Nuclear Toxicology programme, researchers from iRTSV, iBEB and DRFMC have revealed the differential effects of cadmium on DNA repair
in vitro and
in vivo in components of the murine immune system.
In vitro, Cd causes apoptotic death of isolated lymphocytes in just a few hours. These lymphocytes are generally more resistant in organotypic culture systems that partially reproduce a physiological environment, although they demonstrate a severe developmental effect. In vivo, the accumulation of Cd obtained in the thymus after 3 weeks of treatment (supplemental Cd in the drinking water) was comparable to that used in organ cultures. The survival and development of T lymphocytes was not, however, affected by the presence of Cd under either normal conditions or in response to radiation stress; no alteration to the intracellular redox status was observed.
Lastly, a marked accumulation of Cd in the liver and kidneys was observed following intoxication. Despite this, the DNA isolated from these organs did not show any excess oxidative damage. It would therefore appear that the accumulation of Cd through drinking water does not generate new oxidative damage and/or does not perturb the repair systems acting on such damage.
The differential effect of Cd on lymphocytes ex vivo and in vivo and theabsence of damaged DNA underlines the importance of the role of the exposure pathway on the observed effects.
This paper was commented by the "Faculty of 1000 Biology". "This study found a major discrepancy between the effects of cadmium on DNA repair in vivo and in vitro in organ culture. The effects of cadmium on DNA repair after oral exposure in mice were absent, but did occur in the in vitro system. This study clearly points out the issues with making major conclusions based solely on in vitro model systems”.
Viau M, Collin-Faure V, Richaud P, Ravanat JL and Candéias SM
Cadmium and T cell differentiation: Limited impact in vivo but significant toxicity in fetal thymus organ culture.
Toxicology and Applied Pharmacology, 2007
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