The effects of heavy metals Cd^(2+),Pb^(2+)and Zn^(2+)at 0.05,0.5 and 5.0 mg/L level and their interactions at 0.5 mg/L level on DNA damage in hepatopancreas of loach Misgurnus anguillicaudatus for 1-35 days exposure ...The effects of heavy metals Cd^(2+),Pb^(2+)and Zn^(2+)at 0.05,0.5 and 5.0 mg/L level and their interactions at 0.5 mg/L level on DNA damage in hepatopancreas of loach Misgurnus anguillicaudatus for 1-35 days exposure were examined by single cell gel electrophoresis(SCGE).For each test group,20 loaches with similar body size(5.17-7.99 g;11.79-13.21 cm)were selected and kept in aquaria with dechlori-nated water at(22±1)℃and fed a commercial diet every 48 h.According to the percentage of damaged DNA with tail and its TL/D(tail length to diameter of nucleus)value,the relationship between DNA damage degree and heavy metal dose and exposure time was determined.Results showed that the percentage of damaged DNA and the TL/D value were increased with the prolonged exposure time.The highest percentage(84.85%)of damaged DNA was shown in 5.0 mg/L Zn^(2+)group after 28 days exposure and the biggest TL/D value(2.50)in all treated groups after 35 days exposure.During the first treated week,the damnification of DNA was mainly recognized as the first level,after that time,the third damaged level was mostly observed and the percentage of damaged DNA was beyond 80%.The joint toxic effects among Cd^(2+),Pb^(2+)or Zn^(2+)revealed much complexity,but it generally displayed that the presence of Cd^(2+)could enhance the genotoxicity of Pb^(2+)or Zn^(2+).In conclusion,the results suggestedthattherewasasignificanttime-anddose-depended relationship between the heavy metal and DNA damage in hepatopancreas of loach,and SCGE could represent a useful means to evaluate the genotoxicity of environmental contamination on aquatic organisms.展开更多
基金This work was supported by the Key Project of Chinese Ministry of Education(02080)the Open Fund of State Key Laboratory of Freshwater Ecology and Biotechnology,Institute of Hydrobiology,The Chinese Academy of Science(2002FB08).
文摘The effects of heavy metals Cd^(2+),Pb^(2+)and Zn^(2+)at 0.05,0.5 and 5.0 mg/L level and their interactions at 0.5 mg/L level on DNA damage in hepatopancreas of loach Misgurnus anguillicaudatus for 1-35 days exposure were examined by single cell gel electrophoresis(SCGE).For each test group,20 loaches with similar body size(5.17-7.99 g;11.79-13.21 cm)were selected and kept in aquaria with dechlori-nated water at(22±1)℃and fed a commercial diet every 48 h.According to the percentage of damaged DNA with tail and its TL/D(tail length to diameter of nucleus)value,the relationship between DNA damage degree and heavy metal dose and exposure time was determined.Results showed that the percentage of damaged DNA and the TL/D value were increased with the prolonged exposure time.The highest percentage(84.85%)of damaged DNA was shown in 5.0 mg/L Zn^(2+)group after 28 days exposure and the biggest TL/D value(2.50)in all treated groups after 35 days exposure.During the first treated week,the damnification of DNA was mainly recognized as the first level,after that time,the third damaged level was mostly observed and the percentage of damaged DNA was beyond 80%.The joint toxic effects among Cd^(2+),Pb^(2+)or Zn^(2+)revealed much complexity,but it generally displayed that the presence of Cd^(2+)could enhance the genotoxicity of Pb^(2+)or Zn^(2+).In conclusion,the results suggestedthattherewasasignificanttime-anddose-depended relationship between the heavy metal and DNA damage in hepatopancreas of loach,and SCGE could represent a useful means to evaluate the genotoxicity of environmental contamination on aquatic organisms.
