Studying On The Single And Combined Biotoxic Effects Of Multi-class Typical Environmental Pollutants In Vitro

With the increase in the number and variety of contaminants released into environment,the demand for rapid determination and evaluation of biological toxicity of pollutants become an unavoidable issue.The in vitro tools have the advantages of short time-consuming,low cost and simple operation for toxicological evaluation,which makes up for the inherent limitations of chemical and in vivo approaches.Therefore,in this study,we studied the single and combined biotoxic effects of five typical environmental pollutants on ethoxyresorufin-O-deethylase(EROD)activity in Mossambica tilapia liver in vitro.Totally 37 kinds of contaminants,including 13 polycyclic aromatic hydrocarbons(PAHs),five brominated flame retardants(BFRs),three polychlorinated biphenyls(PCBs),six metal ions,and nine pharmaceutically active compounds(PhACs)were studied.Moreover,we conducted a study on screening of DNA damage effect-sensitive cell lines from 11 cell models using comet assay,and applicating to DNA damage effects detection of metals,BFRs and their mixtures.Research indicated:(1)Metal ions(except Zn2+)and PCBs elicited the strongest inhibitory response on EROD activity in a dose-dependent manner.PAHs showed more significant inhibition effects as the number of benzene rings increased.The response of EROD after exposure to BFRs and PhACs was quite different,exhibiting both induction and inhibition effects.(2)Following exposure to binary mixtures of metal ions and BFRs,the EROD activity dose-response curves were similar to those of the metal ions alone,indicating that EROD activity was governed by the metals.(3)11 different cell lines had similar trends in response to DNA damage effects following Cu2+,Cd2+ and Hg2+ exposure,but the sensitivity was different.The results demonstrated that suspended cells were more sensitive to DNA damage effects caused by contaminants,and THP-1 cell was the most sensitive one,according to the linear fitting slope,area under curve(AUC),the lowest observed effect concentration(LOEC),the median effect concentration(EC50),and the classification of DNA damage effects.(4)Co-exposure with metal ions and BFRs could cause an increase in DNA damage effects compared to single metals exposure,which manifested an efifect of toxic amplification.In the present study,we demonstrated the utility of an acute in vitro exposure approach to screen toxic effects of multiple pollutants,which provides a new idea for establishing a rapid and effective method for toxic effects studying of pollutants and environmental monitoring.The dose-response relationship of multi-class pollutants and EROD activity was summarized,providing data support for the application of EROD activity in biotoxicity detection in vitro,also for the establishment of relevant standards for environmental safety and risk assessment.At the same time,it is suggested that in vitro exposure mode is an effective and rapid method to screen the biological toxicity of pollutants.The sensitivity of different cell lines response to DNA damage toxicity were evaluated,provide a reminder to take cell models selection into consideration for the application of DNA damage effects as environmental biomarkers.The jointed effects of contaminants on EROD activity and DNA damage effects were investigated,which provides a basis for standard formulation and environmental safety assessment in the presence of complex pollution in real environments.