DNA damage in fish (Anguilla anguilla) exposed to a glyphosate-based herbicide -- elucidation of organ-specificity and the role of oxidative stress

Mutat Res. 2012 Mar 18;743(1-2):1-9. doi: 10.1016/j.mrgentox.2011.10.017. Epub 2012 Jan 14.


Organophosphate herbicides are among the most dangerous agrochemicals for the aquatic environment. In this context, Roundup(®), a glyphosate-based herbicide, has been widely detected in natural water bodies, representing a potential threat to non-target organisms, namely fish. Thus, the main goal of the present study was to evaluate the genotoxic potential of Roundup(®) in the teleost fish Anguilla anguilla, addressing the possible causative involvement of oxidative stress. Fish were exposed to environmentally realistic concentrations of this herbicide (58 and 116 μgL(-1)) during one or three days. The standard procedure of the comet assay was applied to gill and liver cells in order to determine organ-specific genetic damage. Since liver is a central organ in xenobiotic metabolism, nucleoids of hepatic cells were also incubated with a lesion-specific repair enzyme (formamidopyrimidine DNA glycosylase - FPG), in order to recognise oxidised purines. Antioxidants were determined in both organs as indicators of pro-oxidant state. In general, both organs displayed an increase in DNA damage for the two Roundup(®) concentrations and exposure times, although liver showed to be less susceptible to the lower concentration. The enzyme-modified comet assay showed the occurrence of FPG-sensitive sites in liver only after a 3-day exposure to the higher Roundup(®) concentration. The antioxidant defences were in general unresponsive, despite a single increment of catalase activity in gills (116 μgL(-1), 3-day) and a decrease of superoxide dismutase activity in liver (58 μgL(-1), 3-day). Overall, the mechanisms involved in Roundup(®)-induced DNA strand-breaks showed to be similar in both organs. Nevertheless, it was demonstrated that the type of DNA damage varies with the concentration and exposure duration. Hence, after 1-day exposure, an increase on pro-oxidant state is not a necessary condition for the induction of DNA-damaging effects of Roundup(®). By increasing the duration of exposure to three days, ROS-dependent processes gained preponderance as a mechanism of DNA-damage induction in the higher concentration.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anguilla / genetics*
  • Animals
  • Antioxidants / metabolism
  • Comet Assay
  • DNA Damage*
  • Dose-Response Relationship, Drug
  • Fishes / genetics
  • Gills / drug effects
  • Glycine / analogs & derivatives*
  • Glycine / toxicity
  • Glyphosate
  • Herbicides / toxicity
  • Liver / drug effects
  • Mutagens / toxicity*
  • Organ Specificity
  • Oxidative Stress / physiology*
  • Reactive Oxygen Species / metabolism
  • Water Pollutants, Chemical / toxicity*


  • Antioxidants
  • Herbicides
  • Mutagens
  • Reactive Oxygen Species
  • Water Pollutants, Chemical
  • Glycine