The Toxicity And Mechanisms Of Perfluorinated Compounds On Cynoglossus Semilaevis Liver Cells

Perfluorinated compounds(PFCs) is one kind of organic compounds with 4-14 carbon atoms and the hydrogen completely substituted by fluorine atoms. PFCs are often used as lubricant or additives in textile, papermaking, chemical coating, food packaging and other fields. Among them, perfluorooctane sulfonate(PFOS) and perfluorooctanoic acid(PFOA) attracted much intrest for their wildspread utilization. Recent researches showed that PFOS and PFOA were detected in the seawater and organism samples with persistence and bioaccumulation characteristics. However, the biological toxicity effects and mechanisms of PFOS/PFOA were not very clear yet. In this paper, MTT assay and transmission election microscope(TEM) were used to analyze the activity and morphology with different exposure concentrations and time of PFOS/PFOA on liver cells of cynoglossus semilaevis(HTLC), respectively. Furthermore, reactive oxygen species(ROS) and superoxide dismutase(SOD) activity were applied to evaluate the oxidative damage. On this base, the toxicity mechanism of PFOS/PFOA to HTLC cells could be revealed with the study on transcription of related genes with oxidative stress regulationto reveal.The cell activity was promoted first and inhibited later with the increase of PFOS/PFOA. There was a significant increase(p<0.05) for cytoactive when the concentration of PFOS/PFOA were 200、400 μM and then showed a remarkable inhibition at 1000 μM(p<0.01). Meanwhile, TEM experiments results showed that the organelles were swelled even damaged after exposed to PFOS/PFOA, which might be relevant to metabolism such as intracellular mitochondria and endoplasmic reticulum. The enzymatic experiments indicated that the ROS content was significantly increased with the concentration of PFOS/PFOA at 20 μM(p<0.05). It suggested that FPOS/PFOA could induced oxidative stress effect at low concentrations. When the concentrations increased to 1000 μM, the antioxidant defense mechanisms were started to maintain the redox balance with the regulaton of SOD(p<0.01). The genes results found that the expression of P53, HSP90, NADH and TNF genes had regulated. It suggested that PFOS/PFOA effects may cause cell stress proteins and tumor suppressor factor changes, risk with cancerous cells.In addition, PFOS/PFOA had obviously cytotoxic effect with the repair and damage process. The excess of ROS will lead the damaged of mitochondria, endoplasmic reticulum to the cells by apoptosis program then lead to the cell death or cancer, which may be one of the toxic mechanisms of PFOS/PFOA. There was evaluation of PFOS/PFOA through the toxic effect and the changes of enzymes and genes expression. Thus revealed one toxicity mechanism, provide a scientific basis for the assessment of PFCs in marine environment risk.