Chronic contamination with 137cesium in rat: Effect on liver cholesterol metabolism
Résumé
After the Chernobyl nuclear accident, epidemiological studies on human populations living in 137Cs-contaminated areas revealed the increase frequencies of thyroid cancer and evoked the apparition of cardiovascular diseases, hormonal effect, liver alteration, and lipid disorder. Actually, it raises a problem of public safety for the populations living on these territories that are exposed to low levels of 137Cs during a long period through food. Then it is necessary to study potential effect of this chronic contamination. To mimic this situation, the authors investigate the potential biological effects of chronic exposure to 137Cs at a postaccidental dose (150 Bq/rat/day) on hepatic metabolism of cholesterol in rat. Plasma lipid level, gene expression and activity were analyzed. It was observed that in 137Cs-exposed rats, gene expression of low-density lipoprotein receptor (LDLr), apolipoprotein B (apoB), and liver X receptor α (LXRα) are increased (95%, p < .05; 34%, p < .05; 20%, p < 0.05, respectively), whereas transporter adenosine triphosphate-binding cassette transporter G5 (ABCG5) is decreased (42%, p < .05). In addition, cytochrome P450 27A1 (CYP27A1) activity is increased (34%, p < .05) in contaminated rat liver. In conclusion, the results suggest that 137Cs contamination at low-level induces molecular modifications of the liver cholesterol metabolism without leading to a dysregulation of its homeostasis. These results suggest that chronic long term exposure at low-level of 137Cs may evolve to lipid disorder. Copyright © American College of Toxicology.
Mots clés
ABC transporter A1
ABCG5 protein
apolipoprotein B
cesium 137
cholestanetriol 26 monooxygenase
cholesterol 7alpha monooxygenase
cytochrome P450
hydroxymethylglutaryl coenzyme A reductase
lipid
liver X receptor alpha
low density lipoprotein receptor
sterol regulatory element binding protein
ABC transporter
Abcg5 protein
rat
cell receptor
cesium
cholesterol
DNA binding protein
lipoprotein
liver X receptor
messenger RNA
animal cell
animal experiment
animal model
animal tissue
article
cardiovascular disease
chernobyl accident
cholesterol metabolism
controlled study
endocrine disease
food contamination
gene expression regulation
lipidosis
liver metabolism
liver toxicity
male
molecular biology
nonhuman
radiation hazard
radioactive contamination
receptor binding
thyroid cancer
animal
blood
drug effect
enzymology
gene expression
genetics
liver
liver microsome
liver mitochondrion
metabolism
Sprague Dawley rat
Animals
Apolipoproteins B
ATP-Binding Cassette Transporters
Cesium Radioisotopes
Cholesterol
Cholesterol 7-alpha-Hydroxylase
Cytochrome P-450 CYP27A1
DNA-Binding Proteins
Gene Expression
Lipoproteins
Liver
Male
Microsomes
Mitochondria
Rats
Sprague-Dawley
Receptors
Cytoplasmic and Nuclear
LDL
RNA
Messenger