Lipid accumulation responses in the liver of Rana nigromaculata induced by perfluorooctanoic acid (PFOA)

Abstract

Perfluorooctanoic acid (PFOA) is a perfluorinated compound that is widely distributed, is persistent in the environment, and has a low-level chronic exposure effect on human health. The aim of this study was to investigate the peroxisome proliferator activated receptors γ (PPARγ) and the sterol regulatory element-binding protein 2 (SREBP2) signaling pathways in regulating the lipid damage response to PFOA in the livers of amphibians. Male and female frogs (Rana nigromaculata) were exposed to 0, 0.01, 0.1, 0.5 and 1 mg/L PFOA. After treatment, we evaluated the pathological changes in the liver by Oil Red O, staining and examined the total cholesterol (T-CHO) and triglyceride (TG) contents. The mRNA expression levels of PPARγ, Fatty acid synthase (FAS), Acetyl-CoA carboxylase (ACC), Glycerol-3-phosphate acyltransferase (GPAT), SREBP2 and 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) were measured by quantitative real-time polymerase chain reaction (qRT-PCR). The administration of PFOA caused marked lipid accumulation damage in the amphibian livers. The T-CHO contents were elevated significantly after PFOA treatment; these results show a dose-dependent manner in both sexes. The TG content showed a significant increase in male livers, while it was elevated significantly in female livers. The RT-PCR results showed that the mRNA expression levels of PPARγ, ACC, FAS, GPAT, SREBP2 and HMG-CoA were significantly dose-dependently increased in the PFOA-treated groups compared with those of the control group. Our results demonstrated that PFOA-induced lipid accumulation also affected the expression levels of genes FAS, ACC, GPAT and HMG-CoA in the PPARγ and SREBP2 signaling pathways in the liver. These finding will provide a scientific theoretical basis for the protection of Rana nigromaculata against PFOA effects.