Anesthetic Isoflurane Induces DNA Damage Through Oxidative Stress and p53 Pathway

DNA damage is associated with aging and neurological disorders, including Alzheimer's disease. Isoflurane is a commonly used anesthetic. It remains largely unknown whether isoflurane induces DNA damage. Phosphorylation of the histone protein H2A variant X at Ser139 (gamma H2A.X) is a marker of DNA damage. We therefore set out to assess the effects of isoflurane on gamma H2A.X level in H4 human neuroglioma cells and in brain tissues of mice. Oxidative stress, caspase-activated DNase (CAD), and the p53 signaling pathway are involved in DNA damage. Thus, we determined the interaction of isoflurane with reactive oxygen species (ROS), CAD, and p53 to illustrate the underlying mechanisms. The cells were treated with 2 % isoflurane for 3 or 6 h. The mice were anesthetized with 1.4 % isoflurane for 2 h. Western blot, immunostaining and live cell fluorescence staining were used in the experiments. We showed that isoflurane increased levels of gamma H2A.X, cleaved caspase-3, and nucleus translocation of CAD and decreased levels of inhibitor of CAD (ICAD) and p53. Isoflurane enhanced the nucleus level of gamma H2A.X. Moreover, caspase inhibitor Z-VAD and ROS generation inhibitor N-acetyl-L-cysteine (NAC) attenuated the isoflurane-induced increase in gamma H2A.X level. However, NAC did not significantly alter the isoflurane-induced reduction in p53 level. Finally, p53 activator (actinomycin D) and inhibitor (pifithrin-alpha) attenuated and potentiated the isoflurane-induced increase in gamma H2A.X level, respectively. These findings suggest that isoflurane might induce DNA damage, as represented by increased gamma H2A.X level, via induction of oxidative stress and inhibition of the repair of DNA damage through the p53 signaling pathway.