title: Validation of Drosophila melanogaster as an in vivo model for genotoxicity assessment using modified alkaline Comet assay.
abstract: The single cell gel electrophoresis or Comet assay is one of the most popular techniques for genotoxicity assessment. The present study was undertaken to validate our previously modified version of the Comet assay for genotoxicity assessment in Drosophila melanogaster (Oregon R(+)) with four well-known mutagenic and carcinogenic alkylating agents, i.e. ethyl methanesulfonate (EMS), methyl methanesulfonate (MMS), N-ethyl-N-nitrosourea (ENU) and cyclophosphamide (CP). Third instar larvae (74 +/- 2 h) of D.melanogaster were fed different concentrations of EMS, MMS, ENU and CP (0.05, 0.5 and 1.0 mM) mixed standard Drosophila food for 24 h. At 98 +/- 2 h, the anterior midgut from control and treated larvae were dissected out, single-cell suspensions were prepared and Comet assay was performed. Our results show a dose-dependent increase in DNA damage with all the four alkylating agents, in comparison to control. The lower concentration (0.05 mM) of the test chemicals, except MMS, did not induce any DNA damage in the gut cells of the exposed larvae. When comparison of Comet parameters was made among the chemicals, MMS was found to be the most potent genotoxicant and ENU the least. The present study validated our previous observation and shows that D.melanogaster is a sensitive and suitable model for the in vivo assessment of genotoxicity using our modified alkaline Comet assay.
authors.affiliation: Embryotoxicology Section, Industrial Toxicology Research Center, PO Box 80, M.G. Marg, Lucknow, 226001, Uttar Pradesh, India.
authors.forename: Hifzur R
authors.initials: HR
authors.lastname: Siddique
authors.forename: D Kar
authors.initials: DK
authors.lastname: Chowdhuri
authors.forename: D K
authors.initials: DK
authors.lastname: Saxena
authors.forename: Alok
authors.initials: A
authors.lastname: Dhawan
mesh_terms: D000477:Alkylating Agents / Q000633:toxicity; D000818:Animals; D020552:Comet Assay / Q000379:methods*; D003520:Cyclophosphamide / Q000633:toxicity; D004249:DNA Damage; D004305:Dose-Response Relationship, Drug; D004331:Drosophila melanogaster / Q000187:drug effects / Q000235:genetics*; D005020:Ethyl Methanesulfonate / Q000633:toxicity; D005038:Ethylnitrosourea / Q000633:toxicity; D007814:Larva / Q000187:drug effects / Q000235:genetics; D008741:Methyl Methanesulfonate / Q000633:toxicity; D009152:Mutagenicity Tests / Q000379:methods*; D009153:Mutagens / Q000633:toxicity; D012680:Sensitivity and Specificity
chemical_list: D000477:Alkylating Agents; D009153:Mutagens; D003520:Cyclophosphamide; D005020:Ethyl Methanesulfonate; D008741:Methyl Methanesulfonate; D005038:Ethylnitrosourea