Multi-Biomarkers Approach in Three-Spined Stickleback (Gasterosteus Aculeatus, L.) Using an ENvironmental Biomonitoring Analysis : Genotoxic Biomarkers Integration

Abstract : In order to improve the diagnosis of environmental contamination of freshwater, multi-biomarkers approaches have been developed to better reflect the physiological state of an organism and potentially detect exposures to xenobiotics. Genotoxic biomarkers seem to be quite relevant due to the multitude of substances interacting with the DNA molecule which can affect its integrity in somatic and germ cells. Among the existing tools used to highlight the genotoxicity on fish erythrocytes, the alkaline comet assay (SCGE) is the most widely used method to detect primary DNA strand breaks and flow cytometry (FCM) is becoming a fast and convenient tool to notice chromosomal damages for aquatic biomonitoring. The present work proposes to evaluate the relevance to include two genotoxic biomarkers (primary DNA strand breaks and chromosomal damages) in the existing battery of multi-biomarkers developed on three-spined stickleback (Gasterosteus aculeatus). After 21 days of exposure, biological samples were recovered from sticklebacks caged in six sites in Northern France to constitute the battery. The inclusion of genotoxicity biomarkers seems to bring a little improvement to the discriminating power of sites as obtained by a Principal Component Analysis (PCA) explaining 30.8% of the variance, although they provide a complementary information on the toxicity of sites. The “Rhonelle” river was the most affected by primary DNA strand breaks measured in fish but this parameter was not well represented on axis, in opposition to fish caged in “Deule” and “Sensée Bouchain” sites showing lower levels of chromosomal damages, in accordance with the first component axis of the PCA.