Developmental toxicity and neurotoxicity assessment of R-, S-, and RS-propylene glycol enantiomers in zebrafish (Danio rerio) larvae

Abstract

Propylene glycol (PG) is widely used in the foods, pharmaceuticals, oil industry, animal feed, cosmetics and other industries. Because of the existence of a chiral carbon center, PG forms R (Rectus)-and S (Sinister)-enantiomers. Currently, the toxicity study of its R-, S-enantiomers is still very scarce. In this study, we have assessed the developmental toxicity and neurotoxicity of the R-, S-, and RS-PG enantiomers in zebra sh larvae. We found that exposure to R-, S-, and RS-PG enantiomers did not signi cantly affect the basic developmental endpoints of embryos or larvae (i.e., embryonic movement, hatching, mortality, malformation, heartbeat, body length), indicating that R-, S-, and RS-PG exposures did not exhibit the basic developmental toxicity in zebra sh larvae. The toxicity of the three enantiomers was lower than that of ethanol, and there was no signi cant difference between them. However, R-, S-, and RS-PG exposures with high doses could signi cantly change the eye diameter and the locomotor activity of larval zebra sh, indicating that R-, S-, and RS-PG enantiomers of high doses can potentially exhibit the neurotoxicity and ocular developmental toxicity in zebra sh larvae. Therefore, the potential neurotoxicity and ocular developmental toxicity of R-, S-, and RS-PG enantiomers for infants and toddlers should be considered.