Genotoxic effects of copper sulphate in freshwater planarian in vivo, studied with the single-cell gel test (comet assay)

The alkaline single-cell gel electrophoresis, or comet assay, was used to e valuate the genotoxic potential of copper sulphate in planarians. Concentra tion-related increase in DNA damage was induced after 2 h and 7 days exposu re to CuSO4 dissolved in culture water. To study the influence of copper io ns on the persistence of mutagen-induced DNA lesions, planarians were treat ed with methyl methanesulphonate (MMS), and further incubated in the absenc e (post-incubation) or presence (post-treatment) of CuSO4. After 2 h of pos t-treatment enhanced persistence of DNA effects in relation to the correspo nding post-incubation value was detected, which indicate inhibition of DNA repair by CuSO4. At 4 It an increase of DNA migration in relation to the 2 h value was observed, which is significant for the post-incubation group. A fter 24 h, DNA damage decreased but was still significantly elevated in rel ation to the control. From our results, we conclude that planarians are sui table organisms for in vivo detection of copper genotoxicity in the comet a ssay, and can be used to assess both acute and chronic exposure to this che mical in aquatic ecosystems. The inhibition effect of copper ions on repair of MMS-induced DNA damage suggests that copper could modulate the genotoxi c effects associated with complex mixture exposure in the environment. (C) 2001 Elsevier Science B.V. All rights reserved.