Keywords: 
• PFOS /
• rat /
• liver /
• microRNA

Abstract: The study is aimed to investigate the effects of low-dose exposure of PFOS on microRNA expression pattern and fatty acid metabolism in neonatal rat livers, and reveal the molecular mechanisms of PFOS toxicity to liver functions from the angle of microRNA molecules, then predict other related potential toxic effects. MicroRNA arrays were used to profile the expression of liver microRNA in neonatal rats on postnatal day (PND) 1 and 7, which were exposed to 3.2 mg kg^-1 PFOS at prenatal and neonatal stages, with the control group fed with polyethylene glycol sorbitan monolaurate (Tween 20). Results showed that PFOS exposure induced significant alteration in the expression of 46 and 9 microRNA in liver of rats on PND 1 and PND 7, respectively. MiR-125a-3p, miR-23a*, miR-25 and miR-494 showed significantly downregulated changes on PND1 and upregulated changes on PND7, respectively. The results of bioinformatics and statistics analysis showed that that in PFOS could induce early developmental toxicity to rat livers, which was more significant in embryonic period than that in early lactation. In addition, low-dose PFOS exposure at prenatal and neonatal stages, β and ω oxidative pathways may involve in fatty acid metabolic processes. Acyl COA synthetic enzyme, acyl COA dehydrogenase and enoyl COA hydrated enzyme as the key enzymes of the fatty acid metabolic processes were potential target molecules of microRNA with PFOS exposure. It is indicated that PFOS showed liver early developmental multi-toxicities PFOS exposure at low doses may regulate the expressions of the potential target genes related to fatty acid metabolism by microRNA.