Effects of chronic 137Cs ingestion on barrier properties of jejunal epithelium in rats
Résumé
Environmental contamination by 137Cs is of particular public health interest because of the various sources of fallout originating from nuclear weapons, radiological source disruptions, and the Chernobyl disaster. This dispersion may lead to a chronic ecosystem contamination and subsequent ingestion of contaminated foodstuffs. The aim of this study was to thus determine the impact of a chronic ingestion of low-dose 137Cs on small intestine functions in rats. The animals received 150 Bq per day in drinking water over 3 mo. At these environmental doses, 137Cs contamination did not modify the crypt and villus architecture. In addition, epithelial integrity was maintained following the chronic ingestion of 137Cs, as demonstrated by histological analyses (no breakdown of the surface mucosa) and electrical transepithelial parameters (no change in potential difference and tissue conductance). Furthermore, cesium contamination seemed to induce contradictory effects on the apoptosis pathway, with an increase in the gene expression of Fas/FasL and a decrease in the apoptotic cell number present in intestinal mucosa. No marked inflammation was observed following chronic ingestion of 137Cs, as indicated by neutrophil infiltration and gene expression of cytokines and chemokines. Results indicated no imbalance in the Th1/Th2 response induced by cesium at low doses. Finally, evaluation of the functionality of the jejunal epithelium in rats contaminated chronically with 137Cs did not demonstrate changes in the maximal response to carbachol, nor in the cholinergic sensitivity of rat jejunal epithelium. In conclusion, this study shows that chronic ingestion of 137Cs over 3 mo at postaccidental doses exerts few biological effects on the epithelium of rat jejunum with regard to morphology, inflammation status, apoptosis/proliferation processes, and secretory functions. Copyright © Taylor & Francis Group, LLC.
Mots clés
cesium 137
chemokine
cytokine
drinking water
Fas antigen
FAS ligand
animal experiment
animal model
animal tissue
apoptosis
article
cell count
cell proliferation
cell structure
cellular immunity
cholinergic activity
controlled study
cytokine production
dose response
electric conductivity
electric potential
enteritis
environmental exposure
gene expression
intestine crypt
intestine epithelium
intestine function
intestine villus
long term exposure
male
neutrophil chemotaxis
nonhuman
priority journal
protein expression
rat
Th1 cell
Th2 cell
toxicity testing
Administration
Oral
Animals
Cell Proliferation
Cesium Radioisotopes
Gene Expression
In Situ Nick-End Labeling
Intestinal Mucosa
Jejunum
Male
Rats
Sprague-Dawley
Animalia
Rattus
carbachol