Multi- and Trans-generational Effects of N-ethylpyridinium Bromide on Reproduction and Lipid Metabolism in Caenorhabditis elegans.

Ionic liquids (ILs) belong to emerging pollutants, and their hormesis earned particular attentions on their ecological impacts at low concentrations with long-term exposure. As one representative IL, N-ethylpyridinium bromide ([epyr]Br) was chosen as the target chemical. Its reproductive toxicities on Caenorhabditis elegans were determined with multi- and trans-generational exposure arrangements, and effects on the metabolites and enzyme activities in lipid metabolism were explored to elucidate the mechanisms. In the multi-generational exposure over 11 consecutive generations, [epyr]Br at 0.53 mg⋅L^-1 caused stimulation on the reproduction in F1, F2, F3, F7, F8, F9 and F10, and provoked inhibition in F6 and F11. At 53 mg⋅L^-1, it caused greater inhibitions in more generations than at 0.53 mg⋅L^-1. In the trans-generational influences, [epyr]Br at both concentrations caused significant residual inhibition in the first non-exposed offspring of F1 (i.e., T3). Meanwhile, the residual effects of [epyr]Br exposure at the low concentration in the first non-exposed offspring of F11 (i.e., T3') showed stimulation, and those at the high did not show significant residual effects. The effects of [epyr]Br on the lipid metabolites, e.g., triacylglycerol (TG) and acetyl-CoA (ACA), and those on the activities of enzymes, e.g., glycerol-3-phosphate acyltrans-ferases (GPAT) and carnitine palmitoyl transferase (CPT), also showed oscillation between stimulation and inhibition over generations. Moreover, close relationships were found among the effects of [epyr]Br on the bio-indicators and also between the biochemical effects and the reproductive toxicities with influences by the exposure concentrations. In T3 and T3', [epyr] also showed significant residual effects on the biochemical indicators. Summing up, the reproductive toxicities of [epyr]Br in multi-generational exposure scenario and the residual effects in the trans-generational scenario were closely connected to effects on the lipid metabolism with influences by exposure concentrations. [ABSTRACT FROM AUTHOR]