Abstract

Our aims were to examine whether oxidative DNA damage was elevated in brain cells of male C57BL/6 mice after oxidative stress, and to determine whether neuronal nitric oxide synthase (nNOS) was involved in such damage. Oxidative stress was induced by occluding both common carotid arteries for 90 min, followed by reperfusion. Escherichia coli exonuclease III (Exo III) removes apyrimidinic or apurinic (AP) sites and 3'-phosphate termini in single-strand breaks, and converts these lesions to 3'OH termini. These ExoIII-sensitive sites (EXOSS) can then be postlabeled using digoxigenin-11-dUTP and Klenow DNA polymerase-I, and detected using fluorescein isothiocyanate-IgG against digoxigenin. Compared with the non-ischemia controls, the density of EXOSS-positive cells was elevated at least 20-fold (P