title: [Cytotoxicity and genotoxicity of human cells exposed in vitro to glyphosate].
abstract: BACKGROUND
  Glyphosate is a broad-spectrum non-selective herbicide, used to eliminate unwanted weeds in agricultural and forest settings. Herbicide action is achieved through inhibition of aromatic amino acid biosynthesis in plant cells. Since this is not a conserved mechanism between human and plant cells, glyphosate is considered to be a low health risk substance for humans. However, the occurrence of possible harmful side effects of glyphosate use is not well documented and controversial. Toxicity and genotoxicity studies indicate that glyphosate is not harmful, although several investigations suggest that it can alter various cellular processes in animals. Therfore this has potential as a health and environmental risk factor in areas where glyphosate is widely used.
  
  
  OBJECTIVE
  The present study evaluated glyphosate cytotoxic and genotoxic effects in normal human cells (GM38) and human fibrosarcoma (HT1080) cells.
  
  
  METHODS
  Acute and chronic cytotoxicity were determined through the exposure of cultured cells to graded concentrations of glyphosate, and cell viability analysis was performed with crystal violet and Trypan blue staining. Genotoxicity was determined using the comet assay and data significance was evaluated with Dunnet's test.
  
  
  RESULTS
  For chronic cytotoxicity a dose-dependent effect was observed in both GM38 and HT1080 cells after treatment with 5.2-8.5 mM and 0.9-3.0 mM glyphosate, respectively. In the acute cytotoxicity study, GM38 cells exposed to 4.0-7.0 mM glyphosate and HT1080 cells exposed to 4.5-5.8 mM glyphosate, had cell viability counts higher than 80%. Genotoxic effects were evidenced in GM38 cells at glyphosate concentrations of 4.0-6.5 mM and in HT1080 cells at glyphosate concentrations of 4.75 -5.75 mM.
  
  
  CONCLUSIONS
  The levels of cytotoxicity and genotoxicity of glyphosate occurring in mammalian cells suggested that its mechanism of action is not limited to plant cells.
authors.affiliation: Laboratorio de Genética Humana, Universidad de los Andes, Bogotá, D. C., Colombia.
authors.forename: Claudia Milena
authors.initials: CM
authors.lastname: Monroy
authors.forename: Andrea Carolina
authors.initials: AC
authors.lastname: Cortés
authors.forename: Diana Mercedes
authors.initials: DM
authors.lastname: Sicard
authors.forename: Helena Groot
authors.initials: HG
authors.lastname: de Restrepo
mesh_terms: D002460:Cell Line; D002470:Cell Survival; D020552:Comet Assay; D004791:Enzyme Inhibitors / Q000633:toxicity*; D005998:Glycine / Q000031:analogs & derivatives* / Q000633:toxicity; D006540:Herbicides / Q000633:toxicity*; D006801:Humans; D009152:Mutagenicity Tests; D013223:Statistics as Topic; D000097797:Glyphosate
chemical_list: D004791:Enzyme Inhibitors; D005998:Glycine; D006540:Herbicides; D000097797:Glyphosate