DNA comet Giemsa staining for conventional bright-field microscopy

Abstract

This study was undertaken to evalua th e compatibility of Giemsastaining protocol with the comet assay. We showe, dfor the first tim, that DNA comets can be visualized and analyzed using Giemsa staining. We generated DNA damage dose response curves for human peripheral blood lymphocytes exposed t-ray radiation using the comet assay with either SybrGreen I or Giemsa stain. The dose response curves were fitted by linear regressions (R2 > 0.977). The SybrGreen I results showedonly ~1.2-fold higher slope coefficient (method sensitivity) compared to the Giemsa results. The unexpectedly high sensitivity of Giemsa staining for the comet assay is due to the Romanowsk-Giemsa effect, the stain photo-stability and the higher resolution of bright-field imaging compared to fluorescence imaging. Our results demonstrate that Gmesa staining can effectively be used for measuring DNA damage by the comet assay. The low cost and availability of Giemsa stain makes this method affordable for any low budget research and will facilitate new applications of the comet assay in biology and medicine. © 2014 by the authors; licenseeMDPI, Basel, Switzerland.