Combined Effects Of Triclosan And PCB153 On The DNA Damage And Oxidative Stress In Liver

ObjectiveThe objective is to study the combined effects of triclosan(TCS)and 2,2’,4,4’,5,5’-hexachlorobiphenyl(PCB153)on the DNA damage and oxidative stress in human derived fetal hepatocytes(L02)and the activity of superoxide dismutase(SOD)and the concentration of malondialdehyde(MDA)in zebrafish liver,as well to determine the potential interaction between the two compounds.MethodsThe doses of the TCS-exposed cell experiments were determined based on the results of cell viability via CCK-8 assay.The Tail DNA%and Olive Tailment of the TCS-exposed cells were evaluated by using comet assay.Adult zebrafish were exposed to TCS alone,and the mortality in each group was recorded every 24 h.The 96 h LC50 was calculated to determine the exposure concentrations in subsequent animal experiments.The concentrations of combined exposure groups were determined by the two factor triple factorial design,then the cells and zebrafish were respectively exposed to different combination of the two chemicals.In cell experiments,after 24 and 48 h exposure,the Tail DNA%and Olive Tailment were evaluated by using comet assay,and SOD activity and MDA contents were determined via commercial kits.In zebrafish experiments,the animals in each group were dissected after 5d,10d,14d exposure,and the livers were frozen and stored at-80℃.The SOD activity and MDA content were measured by commercial kits.ResultsThe results of CCK-8 experiment showed that the survival rate of human derived fetal hepatocytes was close to 80%in 0.25μmol/L TCS group.The Tail DNA%and Olive Tailment in 0.025-0.25μmol/L TCS exposure groups were significantly higher than that in the control group(P<0.01).After 24h exposure,the Tail DNA%and Olive Tailment in 0.0625μmol/LTCS + 20μmol/LPCB153 and 0.25μmol/LTCS + 20μmol/LPCB153 combination groups were higher than those in the control group(P<0.05),but lower than those in individuals exposure groups at corresponding concentrations(P<0.05).After 48h exposure,the Tail DNA%and Olive Tailment in 0.0625μmol/LTCS + 20μmol/LPCB153 combination group were higher than those in the control group(P<0.05),but lower than those in individuals exposure groups at corresponding concentrations(P<0.05).There was an interactive effect between TCS and PCB153 on the DNA damage in human derived fetal hepatocytes according to the factorial design data.After 48h exposure,the activities of SOD in 0.0625μmol/LTCS + 5μmol/LPCB153 and 0.0625μmol/LTCS + 20μmol/LPCB153 combination groups were higher than those in the control group and individuals exposure groups at corresponding concentrations(P<0.05).There was an interactive effect between TCS and PCB153 on the activity of SOD in human derived fetal hepatocytes after 48h exposure according to the factorial design data.The results of acute toxicity test showed the 96hLC50 of TCS to adult zebrafish was 2.64μmol/L(792μg/L).After 5 d exposure,the SOD activity of liver in 0.5μmol/LTCS+0.2μmol/LPCB153 combination group were lower than those in the control group and individuals exposure groups at corresponding concentrations(P<0.05).After 10d exposure,the SOD activity of liver in 0.125μmol/LTCS + 0.05μmol/LPCB153 and 0.5μmol/LTCS+0.05μmol/LPCB153 combination groups was lower than those in the control group and individuals exposure groups at corresponding concentrations(P<0.05).After 14 d exposure,the SOD activity of liver in 0.5μmol/LTCS + 0.05μmol/LPCB153 and 0.5μmol/LTCS +0.2μmol/LPCB153 combination groups was higher than those in the control group and individuals exposure groups at corresponding concentrations(P<0.05).There was an interactive effect between TCS and PCB153 on the activity of liver SOD in zebrafish at all three exposure time points.ConclusionThe results of in vitro cell experiment showed that exposure to 0.025～0.25μmol/L TCS caused DNA damage in human derived fetal hepatocytes.Combined exposure to TCS(0,0.0625,0.25μmol/L),PCB153(0,5,20μmol/L)caused varying DNA damage and SOD activities,and the interaction between the two compounds was antagonistic.The results of zebrafish experiments showed that combined exposure to TCS(0,0.125,0.5μmol/L),PCB153(0,0.05,0.2μmol/L)caused varying liver SOD activities,and the interaction between the two compounds was synergistic,while the MDA content had no significant changes.