Multigenerational Hormesis Effects Of [Emim] PF₆ And [Emim] Br On The Reproduction Of Caenorhabditis Elegans

Hormesis,mainly manifested as the inhibitory effect at high concentration and the stimulatory effect at low concentration.In recent years,green solvents ionic liquids have been discovered with hormetic effect to organisms due to their highly water-soluble,difficult to biodegrade,and low recovery rates.They affect the aptical,biochemistry,genes and other indicators of individuals by enhancing the tolerance or resistance of organisms to the environment,and change the overall adaptability of the population,which may in turn affects the balance of the entire ecosystem.In particular,multigenerational toxicity of low-concentration ionic liquids to organisms are particularly important to study.However,there are few studies on the multi-generational hormesis in the existing studies,and in-depth research is urgently needed.In my study,Caenorhabditis elegans(C.elegans)was selected as the test organism were exposured to short-chain imidazole compounds[Emim]Br and[Emim]PF₆to study the multigenerational hormetic effects on the reproduction and the potential mechanism by successive F1-F11 generation and cross-generational disengagement(T4 and T4'generation)exposure,and the changes of key proteins,hormones and epigenetic genes related to reproduction were examined.In addition,Histidine with similar imidazole structure was set as the control group to investigate the effect of imidazole groups on the toxicity of imidazole ionic liquid.The main results were:(1)Reproduction suffered alternative oscillative waves with stimulations and inhibitions, which showed greater or less than 1 fold change of the blank control.8.2E-06 and 8.2E-05 g/L,reproduction was mainly stimulated by[Emim]PF₆and mainly inhibited by [Emim]Br in the F1-F6 generations,where reproduction suffered first peak of stimulation in the F6 generation;then reproduction showed a significant U-shaped curve in the F6-F9 generations in the two ionic liquid groups and reaches the second peak of stimulatory effect in the F9 generation;last,the significant stimulation in the F9 generation was rapidly transformed into an inhibitory effect in the F10 generation,and turned to stimulatory effect in the F11 generation in the[Emim]PF₆group;while was rapidly transformed into an inhibitory effect in the F10 and F11 generations in the [Emim]Br group.8.2E-04 and 8.2E-03 g/L,in the[Emim]PF₆group,reproduction suffered sharpenly stimulation or inhibition in F4-F8 generations,while in F1-F3 and F9-F11 generations was mainly inhibited;in the[Emim]Br group,the reproduction was significantly inhibited in the F1-F8 generations,but in F9,F10,and F11 generations,and the stimulation reached the maximum in the F9 generation.In the T4 generation,the effect of[Emim]PF₆on reproduction was greater than that of[Emim]Br,while in the T4' generation,the stimulatory effect of[Emim]Br was more significant.(2)As the reproductive proteins and hormones,in the[Emim]PF₆and[Emim]Br group,all tested reproduction proteins and hormones were significantly inhibited in both continuous and non-continuous exposure generations;The results in the principal component and Pearson correlation analysis of reproduction and the related reproductive proteins and hormones showed that whether reproduction and MSP and Vn were similarly affected were not consistent with reproduction whether correlated with MSP and Vn,which may indicate that the imidazole ionic liquid was wrongly used by C. elegans,which affected the maturation of the worms eggs and the process of sperm-egg communication and fertilization,thereby significantly stimulating or inhibiting the reproduction of C.elegans.(3)Compared with histidine,the generations whose reproduction was stimulated or inhibited by histidine group were correspondingly stimulated or inhibited in the[Emim]PF₆and [Emim]Br groups.The effect of[Emim]PF₆on the reproduction in the F1-F3 and F9-F11 generations was inconsistent with that in histidine group,except that,[Emim]PF₆and histidine had a high degree of consistent effect on reproduction;[Emim]Br and histidine had a high degree of consistency in the trend of reproduction in all the exposed generations.In the non-continuous exposured generations,[Emim]PF₆mainly with inhibition to reproduction,and histidine mainly with stimulation to reproduction. [Emim]Br and histidine had a smaller effect on the T4 generation;reproduction in the T4' generation suffered more significant stimulation than that in the T4 generation.Similarly, histidine mainly inhibits reproduction-related proteins and hormones in both continuous and non-continuous generations.These results suggest that the improper use of imidazole ionic liquid by C.elegans may be based on the imidazole group structure,which is similar to histidine.(4)At the molecular level,the acs-2 gene encoding acyl-coenzyme A synthase(ACS)in lipid metabolism,akt-1 gene,which regulates glucose and lipid metabolism in the insulin/IGF-1(IIS)pathway,was significantly down-regulated,while set-2,met-2,set-25,and mes-4 were significantly down-regulated in all generations,suggesting that the long-term effects of imidazole ionic liquid on reproduction involved methylation of H3K4,H3K9and H3K36.