Detection of excision repaired DNA damage in the Comet assay by using Ara-C and hydroxyurea in three different cell types

GÜERCI A.; LIVIAC D.; MARCOS R.

CELL BIOLOGY AND TOXICOLOGY

SPRINGER

Año: 2009 vol. 25 p. 73 - 80

0742-2091

Because of its characteristics, the comet assay has been used to evaluate the ability of virtually any type of eukaryotic cell to repair different kinds of DNA damage, including double and single strand breaks and base damage. The ability to detect excision repair sites using the alkaline version can be enhanced by the inclusion of repair inhibitors, DNA synthesis inhibitors or chain terminators. In this sense, we evaluated the ability of hydroxyurea (HU) and cytosine arabinoside (Ara-C), for detecting lesions produced for the alkylating agents ethyl methanesulfonate (EMS) and methyl methanesulfonate (MMS) in three different cell systems. Two hundred cells for experimental point were analyzed in the alkaline version of the comet assay and the results evidence the utility of the assay for detect alkylation of bases in the cells lines MRC-5 and TK-6, since the treatment with HU +Ara-C significantly increases both the basal an induce frequency of DNA damage. The use of whole blood, although detect the effects of MMS, with and without repair inhibitors, failed to detect the effect of the selected dose of EMS and does not permit to detect increases in the background level.