Research On Multi-generational Effect Of N-hexylpyridinium Bromide And N-ethylpyridinium Bromide Against Caenorhabditis Elegans

Ionic liquids,known as green solvents,are emerging as new pollutants and their toxicity studies are of considerable interest.Hormesis effect and time-dependent toxicity of ionic liquids have been reported in recent years,however,multi-generational effect and mechanisms on larger time scales have rarely been explored.Therefore,in this study,Caenorhabditis elegans was divided into blank control group,positive control group(two polycyclic musks),N-hexyl pyridinium bromide([hpyr]Br)and N-ethylpyridinium bromide([epyr]Br)group to investigate the multi-generational effect of two short-chain pyridinium bromide ionic liquids on Caenorhabditis elegans and possible mechanisms,and the main results were as follows.(1)In approximately 10 consecutive generations of exposure,the positive control and the two treatment groups showed multi-generational effect to reproductive on Caenorhabditis elegans at the same toxic effect concentration gradient with temporary irregular stimulationinhibition oscillation compared to the blank control.(2)We also conducted discontinuous exposure experiment with three consecutive generations of first and last exposure generations of detoxification.The positive control group and the two treatment groups had long-term residual effect on reproductive with dosedependent trend compared to the blank control group.Among them,the residual effect of[hpyr]Br and [epyr]Br developed in both different directions(favorable and unfavorable)over generations,while the positive control exhibited the opposite variation at the concentration 2E-8 g/L.(3)In exploring the mechanism of multi-generational effect of [hpyr]Br and [epyr]Br,5-hydroxytryptamine(5-HT),acetoacetyl coenzyme A carboxylase,fatty acid transport protein,and tryptophan hydroxylase were found to play a key role in [hpyr]Br exerting multigenerational effect at different concentrations,where the regulation of adipose triglyceride lipase(ATGL)by 5-HT is not the primary way.In the positive control,the mechanism of toxicity was reproductive regulatory pathway with dose-dependent.Reproductive was positively regulated by total cholesterol and negatively regulated by estradiol in tonalide at2.5E-7 g/L,while major sperm proteins,yolk proteins,and testosterone negatively regulated reproductive at 2.5E-9 g/L.Reproductive was positively regulated by total cholesterol and yolk proteins in galaxolide,at 2.4E-7 g/L,while no significant effects were observed at lower concentrations.In conclusion,N-hexylpyridinium bromide and N-ethylpyridinium bromide have multigenerational reproductive toxicity to Caenorhabditis elegans,and their potential mechanism may be related to lipid metabolism and its regulation.