Effets des paraffines chlorées sur l'expression de gènes clés de Gammarus pulex à deux temps d'exposition

Short-chain chlorinated paraffins (SCCPs) are organic alkane formulations that are released in the environment by industrial processes and electronic waste. They are widely dispersed by wind and water, and therefore have been found in numerous ecosystems and organisms worldwide, where they are not readily biodegradable. This long environmental half-life coupled with continuous dispersal on a planetary scale means that organisms may repeatedly be exposed to them at various time scales. Thus, this work aimed to investigate the effects of SCCPs on the relative mRNA levels of numerous genes involved in vital biological functions (osmoregulation, oxidative stress, the endocrine system, oxygen transportation, immunity and antitoxic defences) of males of the freshwater amphipod Gammarus pulex. They were exposed to environmentally relevant concentrations of SCCPs (10, 100, and 1000 ng/L) at two exposure times (7 and 21 days). Results indicate that SCCPs significantly modified the expression of genes from all the studied functions, depending on exposure time. All studied functions were especially impacted in the acute 7 days exposure, while only the expression of genes involved in oxygen transportation, apoptosis regulation, and antioxidant functions was modified after 21 days. This work concludes that SCCPs impacted the expression of genes coding for antioxidant and antitoxic defences as well as endocrine, osmoregulatory, apoptotic and immune functions of G. pulex at ng/L concentrations, with this effect changing over time. The effects of these contaminants are under-studied in invertebrates, however these results indicate that further investigations may be warranted and needed to understand their potential effects on freshwater ecosystems