Evaluation of tissue morphology and gene expression as biomarkersof pollution in mussel Mytilus galloprovincialis caging experiment

The ecosystem is being anthropogenically disturbed, which has serious consequences for the environ-ment and human health, having strong social and economic impacts on the community. One of the mostcommon methods to evaluate the effects of toxic contaminants is based on biomonitoring, e.g., placingMytilus galloprovincialis in the polluted areas investigated. In this study, we have combined two differ-ent methods, transcriptomic and morphological analysis, with the purpose of determining whether cellmorphology and the ultrastructural organization of our animal model are related to gene expression inoutdoor experiments. The most pronounced changes were observed in mussel gills and digestive glandfor mRNA involved in protein machinery (18S, 28S and EF1), while HSP70, MT10, CYP4Y1, SOD1, and CATmRNAs showed scattered modifications not related to the studied area. In agreement with 18S, 28S, andEF1 mRNA evaluation, optical and electron microscopy demonstrated an initial inflammatory responseof the cells that can lead to apoptosis in the caged mussels in all the polluted areas. In conclusion, theapplication of a multi-disciplinary approach proved to be effective for assessing the biological effects ofcontaminations on the health of aquatic organisms, and thus suitable to be applied in eco-toxicologicalstudies. Although affected by several uncontrolled environmental variables, the assessment of mRNA canrepresent a useful endpoint for an integrated estimation of the overall threats to the sea environmentwithin a field research approach.© 2016 The Authors. Published