| Ionic liquids(ILs)are a new class of polar solvents with good chemical and thermal stability that can be used to replace traditional volatile and toxic solvents.With the wide use of ILs in industry,they will enter soil and even groundwater systems,persist in the environment for a long time.At present,there have been many reports on the acute toxicity of ILs,but there are still few studies on the whole life cycle effect from egg to larva to adult.In this study,using Caenorhabditis elegans as a model organism,two kinds of pyridine based ILs,[bpyr]Cl and[bpyr]Br,four kinds of quaternary ammonium based ILs including BTAB,OTAB,DTAB and CTAB,were selected for whole life exposure.Apical indicators such as lifespan,initial reproduction,total reproduction,number of fertilized eggs,and biochemical indicators related to oxidative stress were detected.The toxic effects of ILs and its mechanism of production were explored through SKN-1,m TOR and NF-κB signaling pathways,as well as the regulatory pathways of oxidative stress.Findings were as follows:(1)The results of the life-cycle toxicity of exposure to[bpyr]Cl and[bpyr]Br on nematodes showed that both ILs significantly inhibited initial and total reproduction,but had little effect on lifespan.Further biochemical analysis showed that the content of ROS was also significantly increased,resulting in oxidative stress and oxidative damage.However,the antioxidant enzyme activity of[bpyr]Cl was higher than that of[bpyr]Br,probably due to a different mechanism of toxic action.In addition,the toxicity of[bpyr]Cl and[bpyr]Br,it was found that Br~-was more toxic to the reproduction of C.elegans than Cl~-.(2)By studying the toxic effects of BTAB,OTAB,DTAB and CTAB on nematodes throughout their life cycle,the results showed that BTAB also has hormesis effects on nematodes.OTAB,DTAB and CTAB significantly inhibited reproduction,but had no significant effect on lifespan.Further biochemical results showed that SKN-1 was significantly reduced at 30ppm OTAB and DTAB,SOD activity was inhibited at CTAB,and vab-1 was inhibited at BTAB and DTAB,but the overall changes were not significant and the degree of inhibition did not exceed 20%.In addition,by comparing the toxicity of these four ILs,the results showed that the toxicity of ILs increased with longer alkyl side chain length,showing an overall order of:CTAB>DTAB>OTAB>BTAB.A concentration-effect relationship was also observed,with high concentration of ILs being more toxic than low concentration of ILs.(3)The concomitant addition of SKN-1,m TOR,and NF-κB signaling pathway inhibitors to ILs-exposed nematodes.The results showed that ROS production was stimulated by m TOR inhibitor and co-exposure of the three inhibitors.When m TOR and SKN-1,and the three signaling pathway inhibitors were exposed together,SKN-1 was significantly inhibited.Exposure to some inhibitors alone and in combination resulted in significant inhibition of ROS content,and these experimental groups all contained Brusatol,a SKN-1 inhibitor.In addition,the study found that there was a large contrast between the apical and biochemical indicators,with significant changes in the apical indicators after nematodes were exposed to inhibitors and ILs simultaneously.For example,the combination of PDTC and Rapamycin inhibitor and the combination of three inhibitors significantly inhibited the initial reproduction and total reproduction after adding 30ppm BTAB.The experimental groups with Brusatol inhibitor and the mixed experimental groups with PDTC and Brusatol significantly stimulated initial and total reproduction of nematodes after the addition of 30ppm BTAB.However,biochemical indicators had little effect.In summary,we found that ILs can produce toxic effects on nematodes and induce oxidative stress,causing oxidative damage.Moreover,different types of ILs have different toxicity and action mechanisms.Future studies can further explore the mechanism of ILs drug production at the genetic level. |
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