Neuro-inflammatory response in rats chronically exposed to 137Cesium

After the Chernobyl nuclear accident, behavioural disorders and central nervous system diseases were frequently observed in populations living in the areas contaminated by 137Cs. Until now, these neurological disturbances were not elucidated, but the presence of a neuro-inflammatory response could be one explanation. Rats were exposed for 3 months to drinking water contaminated with 137Cs at a dose of 400 Bq kg−1, which is similar to that ingested by the population living in contaminated areas in the former USSR countries. Pro-inflammatory and anti-inflammatory cytokine genes were assessed by real-time PCR in the frontal cortex and the hippocampus. At this level of exposure, gene expression of TNF-α and IL-6 increased in the hippocampus and gene expression of IL-10 increased in the frontal cortex. Concentration of TNF-α, measured by ELISA assays, was also increased in the hippocampus. The central NO-ergic pathway was also studied: iNOS gene expression and cNOS activity were significantly increased in the hippocampus. In conclusion, this study showed for the first time that sub-chronic exposure with post-accidental doses of 137Cs leads to molecular modifications of pro- and anti-inflammatory cytokines and NO-ergic pathway in the brain. This neuro-inflammatory response could contribute to the electrophysiological and biochemical alterations observed after chronic exposure to 137Cs.