Effets des paraffines chlorées sur l'expression de gènes clés de Gammarus pulex à deux temps d'exposition | Effects of Short-Chain Chlorinated Paraffins on the Expression of Key Genes of Gammarus pulex at Two Exposure Times

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