| Perfluorinated Compounds(PFCs)are persistent organic compounds that are com pletely replaced by hydrogen atoms in carbon atoms.They are commonly used as add itives in textiles,packaging,and chemical coatings.In recent years,the highest concen tration of perfluorinated compounds,the most typical perfluorooctane sulfonate(PFOS),has been detected in seawater and sediments in coastal waters of China,especially in aquatic organisms.Bioaccumulation,the current toxicity study of PFOS on aquatic org anisms is mainly concentrated in model fishes such as Danio rerio and Oryziaslatipes,but the toxicity study of PFOS on marine economic fish is very scarce.In this paper,the cynoglossus semilaevis was used as the test organism,and the antioxidant defenses ystems(SOD,CAT,POD,GSH,GST,Ach E,EROD)of the larvae of PFOS and PFO S potassium salt(PFOS-K)under different long-term stress were compared.Responsecha racteristics of hormone receptor pathway-related gene expression(AR,ER?,ER?,AHR,ARNT).At the same time,the toxic effects of PFOS and PFOS-K were comprehensi vely evaluated using the Integrated Biomarker Responses(IBR)method.A comprehensiv e evaluation of the POPs PFOS and PFOS-K provides a reference for marinetoxicity.In this paper,PFOS and PFOS-K were first set in three concentration groups,0.1?g·L-1,10?g·L-1 and 100?g·L-1,respectively,and one blank control group was set at the same time.Fish liver and sputum samples were taken on the 1st,3rd,7th and 15th day after stress,and the cynoglossus semilaevis were divided into 8 groups,20 individuals in each group,and each group was three parallel.Semi-static experimental method for measurement,including cynoglossus semilaevis liver and sputum antioxidant Effects of systemic indicators(SOD,CAT,POD,and GSH)and biometabolizing enzyme systems(GST,EROD,and Ach E).The results showed that each enzyme activity had different degrees of oxidative stress on the liver and sputum of the cynoglossus semilaevis.The CAT activity of liver and sputum in the cynoglossus semilaevis was significantly promoted under PFOS stress.The highest in the 0.1?g·L-1 group was 12.01 U·mgprot-1and 2.01 U·mgprot-1 were 1.54 and 2.71 times of the blank group,respectively.Under the stress of PFOS and PFOS-K,the content of GST in the liver and sputum of the cynoglossus semilaevis was induced.When PFOS-K was exposed for15 days,the GST content in the 0.1?g·L-1 group reached the highest,which was 55.65U·mgprot-1,which was 4.56 times that of the blank group.And also promote the Ach E activity in the liver of the cynoglossus semilaevis.Under different concentrations of PFOS and PFOS-K,sputum is more oxidatively damaged than liver.And PFOS-K induced more cells than PFOS,indicating that PFOS-K is more toxic to fish than PFOS.This indicates that PFOS and PFOS-K can cause oxidative damage to marine fish cells and correlate with concentration and exposure time.SOD,GST,POD,CAT,Ach E,EROD activity trends and GSH content can be used as indicators for the detection and evaluation of PFOS and PFOS-K toxicity mechanisms.Secondly,the expression levels of AR,ER?,ER?,AHR and ARNT in PFOS and PFOS-K in the liver of cynoglossus semilaevis were significantly different under different concentrations of PFOS and PFOS-K.The expressions of AR,AHR,ARNT and ER?genes showed a trend of gradually returning to the control group after prolonged exposure time of the pollutants,and there was a certain time effect and dose-effect relationship.At 15 d,all AR and ARNT gene expression levels were inhibited,but the degree of inhibition was different.The change trend of AHR gene expression was increased first and then decreased.The relative expression of AHR at the concentration of 0.1?g·L-1 at PFOS-K exposure was 23.69times higher than that of the blank group at 7 days.There was no significant difference in PFOS exposure.The expression level of ER?gene was significantly changed in the late stage of stress.PFOS-K was more significant than PFOS in gene expression.The above results indicated that ER?,ER?,AR and ARNT were expressed in the liver tissues of the semi-smooth tongue,indicating that the hormone and other receptor genes may be involved in the toxicity mechanism,and the expression of related genes of PFOS and PFOS-K on hepatic hormone receptors in the cynoglossus semilaevis.The amount of influence varies.Finally,a comprehensive systematic evaluation of the toxic effects of PFOS and PFOS-K was performed using the integrated bioresponse index.The results showed that the effect of PFOS on the liver and sputum integrated biomarkers of the cynoglossus semilaevis was in the same dose group,and the cells IBR value was greater than that of the liver during the same exposure time.organization.In the same dose group as PFOS-K,the area of the IBR stellate area of the sputum tissue was larger than that of the sputum tissue and liver tissue at the same sampling time.However,in the effects of PFOS and PFOS-K cynoglossus semilaevis liver gene integration biomarkers,it was found that PFOS-K had a larger RIB stellate area than PFOS-K at the same time point.A reference value is determined for determining the indicator of the marker organism.This experiment not only reveals the toxic mechanism of two perfluorochemicals through antioxidant system and gene expression changes,but also provides a scientific basis for assessing the marine environmental risks of PFCs. |
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