To clarify the relationship between mitochondrial DNA (mtDNA)-depleted rho 0 cells and the cellular sensitivity to hydrogen peroxide (H2O2), we established Hela and SAS rho 0 cell lines and investigated their survival rate in H2O2, radical scavenging enzymes, plasma membrane potential status, and chronological change in intracellular H2O2 amount under the existence of extracellular hydrogen peroxide compared with the parental cells. The results revealed that rho 0 cells had higher sensitivity to H2O2 than their parental cells, even though the catalase activity of rho 0 cells was up-regulated, and the membrane potential of the rho 0 cells was lower than their parental cells. Furthermore, the internal H2O2 amount significantly increased only in rho 0 cells after 50 mu M H2O2 treatment for 1 h. These results suggest that plasma membrane status of rho 0 cells may cause degradation, and the change could lead to enhanced membrane permeability to H2O2. As a consequence, rho 0 cells have a higher H2O2 sensitivity than the parental cells. (C) 2017 Elsevier Inc. All rights reserved.