Feeding mice with diets containing mercury-contaminated fish flesh from French Guiana: A model for the mercurial intoxication of the Wayana Amerindians
Environ Health. 2008-10-29; 7(1):
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1. Environ Health. 2008 Oct 29;7:53. doi: 10.1186/1476-069X-7-53.
Feeding mice with diets containing mercury-contaminated fish flesh from French
Guiana: a model for the mercurial intoxication of the Wayana Amerindians.
Bourdineaud JP(1), Bellance N, Bénard G, Brèthes D, Fujimura M, Gonzalez P,
Marighetto A, Maury-Brachet R, Mormède C, Pédron V, Philippin JN, Rossignol R,
Rostène W, Sawada M, Laclau M.
(1)Université de Bordeaux 1-CNRS UMR 5805, Station Marine d’Arcachon, place du
Docteur Peyneau, Arcachon, France.
BACKGROUND: In 2005, 84% of Wayana Amerindians living in the upper marshes of the
Maroni River in French Guiana presented a hair mercury concentration exceeding
the limit set up by the World Health Organization (10 microg/g). To determine
whether this mercurial contamination was harmful, mice have been fed diets
prepared by incorporation of mercury-polluted fish from French Guiana.
METHODS: Four diets containing 0, 0.1, 1, and 7.5% fish flesh, representing 0, 5,
62, and 520 ng methylmercury per g, respectively, were given to four groups of
mice for a month. The lowest fish regimen led to a mercurial contamination
pressure of 1 ng mercury per day per g of body weight, which is precisely that
affecting the Wayana Amerindians.
RESULTS: The expression of several genes was modified with mercury intoxication
in liver, kidneys, and hippocampus, even at the lowest tested fish regimen. A net
genetic response could be observed for mercury concentrations accumulated within
tissues as weak as 0.15 ppm in the liver, 1.4 ppm in the kidneys, and 0.4 ppm in
the hippocampus. This last value is in the range of the mercury concentrations
found in the brains of chronically exposed patients in the Minamata region or in
brains from heavy fish consumers. Mitochondrial respiratory rates showed a 35-40%
decrease in respiration for the three contaminated mice groups. In the muscles of
mice fed the lightest fish-containing diet, cytochrome c oxidase activity was
decreased to 45% of that of the control muscles. When mice behavior was assessed
in a cross maze, those fed the lowest and mid-level fish-containing diets
developed higher anxiety state behaviors compared to mice fed with control diet.
CONCLUSION: We conclude that a vegetarian diet containing as little as 0.1% of
mercury-contaminated fish is able to trigger in mice, after only one month of
exposure, disorders presenting all the hallmarks of mercurial contamination.
PMID: 18959803 [Indexed for MEDLINE]