Intergenerational effects of parental [C_nmim]BF₄ (n = 4, 6, 8) ionic liquids exposure on zebrafish development based...

Ionic liquids (ILs) have been developed as alternatives to traditional solvents, and their toxicity may be affected by alkyl chain length. Currently, there is limited evidence for whether parental exposure to different alkyl chain length ILs will induce intergenerational toxicity in zebrafish offspring. To address this knowledge gap, the parental zebrafish (F0) were exposed to 25 mg/L [C_nmim]BF₄ (n = 4, 6, 8) for 7 days. Following this, fertilized F1 embryos from the exposed parents were reared in clean water for 120 h. Increased mortality, higher deformity rate, increased pericardial edema rate, and a shorter swimming distance and average speed were detected in the unexposed F1 embryonic larvae from the exposed F0 compared to the F1 generation from the unexposed F0. Parental exposure to [C_nmim]BF₄ (n = 4, 6, 8) resulted in cardiac malformations and dysfunction in F1 larvae, including increased pericardial areas, increased yolk sac areas and decreased heart rate. Moreover, the intergenerational toxicity of [C_nmim]BF₄ (n = 4, 6, 8) in F1 offspring appeared to be alkyl chain length-dependent. Parental [C_nmim]BF₄ (n = 4, 6, 8) exposure led to global transcriptomic changes involved in developmental processes, nervous system process, cardiomyopathy, cardiac muscle contraction, and metabolic signalling pathways such as PI3K-Akt, PPAR and cAMP pathways in unexposed F1 offspring. Overall, the present study provides evidence that the neurotoxicity and cardiotoxicity of ILs in zebrafish can be markedly transmitted to offspring, and the intergenerational developmental toxicity is probably linked to transcriptomic alterations, highlighting the necessity of assessing ILs' environmental safety and human health risks.