Optimisation of Arabidopsis thaliana DNA extraction for the analysis of 8-oxo-7,8-dihydro-2'-deoxyguanosine formation after gamma irradiation

8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) is a major oxidative DNA lesion. Plant DNA extraction protocols were improved in order to quantify 8-oxodGuo in the overall DNA of a cell suspension of Arabidopsis thaliana using the method of high performance liquid chromatography with electrochemical detection (HPLC-EC). Our results show that DNA can be artefactually oxidised during the extraction procedure. Metal chelating agents were efficient to decrease the 8-oxodGuo background level to $3.3 \pm 0.1 8$-oxodGuo/105Gua and to improve experiment reproducibility. It was observed that DNA guanine oxidation in plant cells by γ-rays is very low in vivo (15 8-oxodGuo/109Gua formation per Gy)