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Immunotoxicity of surface waters contaminated by municipal effluents to the snail Lymnaea stagnalis

Gust, Marion; Fortier, Marlène; Garric, Jeanne; Fournier, Michel; Gagné, François (2013). Immunotoxicity of surface waters contaminated by municipal effluents to the snail Lymnaea stagnalis Aquatic Toxicology , vol. 126 . p. 393-403. DOI: 10.1016/j.aquatox.2012.09.001.

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Résumé

The immunotoxic effects of surface waters contaminated by a municipal effluent dispersion plume were examined in the snail Lymnaea stagnalis. Snails were exposed to surface waters where changes in hemocyte counts, viability, levels of reactive oxygen species (ROS), reduced thiols and phagocytic activity were tracked following exposure periods of 3. h and 3 and 7. d. Changes in mRNA expression of some genes in the hemocytes were also assessed after 7. d of exposure, as follows: genes coding for catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GSR), selenium-dependent glutathione peroxidase (SeGPX), two isoforms of the nitric oxide synthetase (NOS1 and NOS2), molluscan defensive molecule (MDM), toll-like receptor 4 (TLR4), allograft inflammatory factor-1 (AIF), and heat-shock protein 70 (HSP70). At the sites closest to the discharge point, exposure led to impaired hemocyte viability and intracellular thiol levels and also an increase of hemocyte count, ROS levels and phagocytosis. Phagocytosis and ROS levels in hemocytes were correlated with heterotrophic bacterial counts in snails. We found four genes with increased mRNA expression as a response to exposure of municipal wastewaters: TLR4 (6-fold), HSP70 (2-fold), SeGPx (4-fold) and CAT (2-fold). Immunocompetence responses were analyzed by canonical analysis to seek out relationships with mRNA expression of the genes involved in stress, pattern recognition, cellular and humoral responses. The data revealed that genes involved in oxidative stress were strongly involved with immunocompetence and that the resulting immune responses were influenced both by the bacterial and pollutant loadings of the effluent. © 2012 Elsevier B.V.

Type de document:
Mots-clés libres: Cytometry Gene expression Immune response Lymnaea stagnalis Urban effluent
Centre: Centre INRS-Institut Armand Frappier
Date de dépôt: 04 avr. 2017 15:56
Dernière modification: 04 avr. 2017 15:56
URI: http://espace.inrs.ca/id/eprint/2916

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