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Une étude démontre des effets "épigénétiques" sur l'ADN d'un polluant à faible dose au stade périnatal - Dr Nora Benachour

Lundi 12 Janvier 2015

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Une ancienne étudiante du Pr Séralini, le Dr Nora Benachour, qui a obtenu son doctorat avec lui à l'Université de Caen en 2008, vient de contribuer à montrer au Canada avec l'Université de Sherbrooke qu'un polluant commun, retardateur de flamme, avait des effets "épigénétiques" sur l'ADN de nouveau-né de rat, dans le lobe frontal du cerveau. Les polluants contribuent ainsi de manière délétère à un habillage chimique anormal du patrimoine génétique dans certains organes. Nous nous félicitons du fait que des anciens étudiants du Pr. Séralini soient à la pointe de la recherche dans le monde.

 

 

 

 

 

 

 

 

 

Toxicology 328 (2015) 152–159

 

Epigenetic effects of low perinatal doses of flame retardant BDE-47 on mitochondrial and nuclear genes in rat offspring


Hyang-Min Byun a , Nora Benachour b , Daniel Zalko c , Maria Chiara Frisardi d,e ,Elena Colicino e , Larissa Takser b,1 , Andrea A. Baccarelli a,1, *


a Laboratory of Environmental Epigenetics, Exposure Epidemiology and Risk Program, Harvard School of Public Health, Boston, MA 02115, USA
b Département Pédiatrie, Faculté de Médecine, Université de Sherbrooke, QC J1H 5N4, Canada
c Institut National de la Recherche Agronomique, UMR1331, TOXALIM (Research Centre in Food Toxicology), Toulouse, France
d Department of Statistics, University of Milano-Bicocca, Milan 20126, Italy
e Department of Environmental Health, Harvard School of Public Health, Boston, MA 02115, USA

 

ABSTRACT
Polybrominated diphenyl ethers (PBDEs) are known endocrine disrupting chemicals used commonly as flame retardants in everything from electronics to furniture. Exposure to PBDEs during early development has been linked to neurodevelopmental delays. Despite mounting evidence of neurological harm from PBDE exposure, the molecular mechanisms underlying these effects on brain function remain unknown. We examined the effects of perinatal exposure to BDE-47, the most biologically active and prevalent BDE congener in North America, on epigenetic patterns in the frontal lobe of Wistar rats. Dams were gavaged with BDE-47 (0.002 and 0.2 mg/kg body weight) at gestation days 9 and 16, and postnatal days 1, 8, and 15. Frontal lobes from offspring at postnatal day 41 were collected to measure 5-methylcytosine (5mC) in mitochondrial cytochrome c oxidase genes (Mt-co1,Mt-co2, and Mt-co3), global nuclear 5-hydroxymethylcytosine (5hmC) content, 5mC in repetitive elements L1Rn, and 5mC in nuclear genes (Bdnf, Crhr1, Mc2r, Nr3c1, and Snca) related to behavioral and brain functions in the nuclear genome. We observed a significant decrease in %5mC in Mt-co2 (difference from control = À0.68%, p = 0.01 at the 0.2 mg/kg BDE-47). 5mC in repetitive elements L1Rn decreased at 0.002 mg/kg BDE-47 (difference = À1.23%, p = 0.02). Decreased nuclear 5mC was observed in Bdnf and Nr3c1 in BDE-47 exposed rats. However, we did not observe significant effects of PBDE toxicity on DNA methylation patterns for the
majority of genes in the brain.

 

Online article : http://www.sciencedirect.com/science/article/pii/S0300483X14002583