Step-wise reproductive toxicities of imidazolium- and pyridinium-based ionic liquids on Caenorhabditis elegans

Reproductive toxicities of imidazolium- ([EMIM]X) and pyridinium-based ([APYR]X) ionic liquids (ILs) are essential to fully assess their hazards. Presently, effects of five ILs on the intricate processes of reproduction, including sperm-oocyte interactions, were explored in Caenorhabditis elegans . Results showed that 1-ethylpyridinium bromide ([EPYR]Br) stimulated oocytes, zygotes and total reproduction. 1-Octylpyyridinium bromide ([OPYR]Br) inhibited oocytes and stimulated zygotes, it inhibited the initial and total reproduction. 1-Dodecylpyridinium bromide ([DPYR]Br) inhibited oocytes and zygotes, but stimulated the initial and total reproduction. 1-Ethyl-3-methylimidazolium bromide ([EMIM]Br) inhibited oocytes, but stimulated zygotes and reproduction. 1-Ethyl-3-methylimidazolium iodide ([EMIM]I) inhibited germcells and oocytes but stimulated zygotes and reproduction. Regarding hormones and lipid metabolism, the ILs commonly reduced main sperm protein, sperm transmembrane protein 9 and spermatocyte protein 8. The qRT-PCR results showed that the ILs commonly down-regulated the expressions of mpk-1 , while up-regulated those of inx-14 , with influences on the expressions of vab-1 , unc-43 and rme-2 . These biochemicals and genes were directly connected with the sperm-oocyte interactions. Transcriptomic analysis results supported the involvement of cAMP and cGMP-PKG signaling pathways underlying the effects on the sperm-oocyte interactions. The results also implied ILs’ impacts on neural and immune diseases and even cancers that should be considered in the future.