Disturbance Effect Of Perfluorooctane Sulfonate And Perfluorooctanoic Acid On Lipid Metabolism In BALB/c Mice

Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) as predominant perfluorinated compounds (PFCs), have received wide concentrations for their toxic effects. In this study, BALB/c mice were chosen as target animals and fed with regular diet (RD) or high fat diet (HFD), aimed to learn the effects of PFOS and PFOA on their lipid metabolism system. Furthermore, with comparison between results of the two PFCs, the potential mechanisms of their toxic effects were explored. This study can provide a scientific evidence for the evaluation on the safety of PFCs.PFOS treated mice displayed following changes:Decreased body weight and feed consumption were observed; Serum cholesterol (CHOL) and triglyceride (TG)were reduced; High-density lipoprotein cholesterol (HDL-ch) as well as low-density lipoprotein cholesterol (LDL-ch) level was changed; Serum thyroid hormone free T3(FT3) and free T4(FT4) levels were decresed, estradiol level was aslso affected; Reduced serum glucose level and decreased liver glycogen content were detected; The function of liver was affected and fat content in liver was significantly increased, histological analysis showed the vacuolation and hypertrophy of hepatic cells; Transmission electron microscope (TEM) images noted the serious lipid droplet accumulation as well as dilatation of endoplasmic reticulum; Altered expression of PPARa, PPARyand other genes involved in catabolism of fatty acids and cholesterol were also detected. Significant differences could be observed between RD and HFD individuals, as well as male and female mice.PFOA treated male mice displayed following changes:Decreased body weight and feed consumption were observed; Serum cholesterol(CHOL) and triglyceride(TG)were reduced; High-density lipoprotein cholesterol(HDL-ch) as well as low-density lipoprotein cholesterol (LDL-ch) level was changed; Reduced serum glucose level and decreased liver glycogen content were detected; Liver MDA content was significantly increased while SOD, GPT as well as LDH activities were inhibited; Histological analysis showed ballooning degeneration and the hydropic degeneration with visible vacuoles in hepatocytes. TEM images noted the dilatation of endoplasmic reticulum as well as mitochondria cristae. Interestingly, unlike the PFOS-exposed cells, the lipids occurred in the nucleus; Altered expression of PPARa, PPARγand other genes involved in catabolism of fatty acids and cholesterol were also detected. Similarly, these results displayed significant differences between RD and HFD individuals. With the obtained results above, it could be concluded that:PFOS and PFOA resembles FA in their structures, they might disturb the transport and metabolism of FA in blood as well as cells; they might also interfere in the excretion of LDL, leading to the abnormal lipid exportation from liver to peripheral tissues, and finally resulted in the accumulation of lipids in the liver. Comparing with the various results of PFOS and PFOA, it was speculated that the different toxic mechanisms of the two might existed. However, further studies should be carried out to confirm those conclusions.