Toxicity Of Bisphenol Af And Perfluorinated Chemicals On Zebrafish

Bisphenol AF (BPAF) and perfluorinated chemicals (PFCs) are the new types of organofluorine compounds which have recently received much attention. As one of analogues of bisphenol A (BPA), BPAF is increasingly being incorporated into the production of fluoropolymers, fluoroelastomers, and a variety of polymers that are used to make electronic devices and plastic optical fibers. The endocrine-disrupting effects of BPAF have been documented in vitro, but little is known about its effects on fish. PFCs are widely used in the stain resistant treatments for textiles, leather and carpets, tireretardants and insecticides due to their hydrophobicity as well as lipophobicity. However, limited information about its impact on fish and rodent animals available. In this study, adult zebrafish (Danio rerio) and zebrafish embryo were used as animal models to detect the potential toxicity and endocrine-disrupting effects of BPAF. Likewise, zebrafish embryo was used to investigate the toxic effects of six PFCs, including perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorohexanesulfonic acid potassium salt (PFHS), perfluorohexanoic acid (PFHA), perfluorobutansulfonic acid potassium salt (PFBS), perfluorobutanoic acid (PFBA). The results of our study are shown in the following points.1.After exposure to0,0.05,0.25or1mg/L BPAF for28d, the weight and length of zebrafish were not affected. There was no difference in Superoxide Dismutase (SOD) activity and Malondialdehyde (MDA) content in the liver among the control and treatment groups. In male fish, the testosterone (T) levels in the whole-body homogenates were significantly reduced but the estradiol (E2) levels increased. BPAF caused damages to the liver and gonad, such as hepatocellular swelling and vacuolation, reduction of sperm in the testis and retardation of oocyte development in the ovary. In addition, BPAF can dramatically induce the Vitellogenin (VTG) expression in the liver of male fish, and the VTG expression of female fish was increased, too. Our results indicate that BPAF can exert endocrine-disrupting effects and the harm of BPAF at environmental concentrations needs further study.2. BPAF led to the concentration-dependent increase of mortality and decrease of hatching rate in zebrafish larva. BPAF exhibited cardiac toxicity to the larva, characterized by blood cell accumulation in the heart area, pericardial edema, slow heart-beating rate, the block of blood circulation and arrhythmia. Meanwhile, the failed inflation of gas bladder was observed in the BPAF-treated groups, and the malformation rate increased with the increasing concentration. BPAF exposure, binary exposure of BPAF and estradiol inhibited the expression of VTG.3. Our results of embryo exposed to six PFCs revealed that the PFCs with different chain lengths and functional groups caused different lethal effect and teratogenic effect. The mortality in the groups treated by PFOS, PFHS or PFBS was increased in a concentration-dependent manner. Meanwhile, PFOS, PFHS or PFBS exposure resulted in the failed inflation of gas bladder or curve spine. The order of lethal effect and teratogenic effect was:PFOS>PFHS>PFBS. In addition, there were no death or malformation in the groups exposed to PFOA, PFHA or PFBA, suggesting that PFCs with a sulfonate group exerted more toxic potential than the ones with a carboxyl group. The results of gene expression showed that there were no significant difference on the expression of VTG after PFOS, PFOA, PFHS, PFHA, PFBS or PFBA exposure.