산화적 스트레스에 의한 간세포의 DNA 손상 및 세포사멸 유도에 미치는 원지 에탄올 추출물의 보호 효과

The Protective Effect of Ethanol Extract of Polygalae Radix against Oxidative Stress-Induced DNA Damage and Apoptosis in Chang Liver Cells

Objectives: The purpose of the present study was to evaluate the preventive effects of ethanol extract of Polygalae radix (EEPR) against oxidative stress (hydrogen peroxide, H2O2)-induced DNA damage and apoptosis in Chang liver cells. Methods: Chang liver cells were pretreated with various concentrations of EEPR and then challenged with 0.5 mM H2O2. The cell viability and apoptosis were assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and flow cytometry analysis, respectively. The levels of reactive oxygen species (ROS), mitochondrial membrane potentials (MMPs) and adenosine tri-phosphate (ATP) contents were measured. Expression levels of Bcl-2 and Bax were also determined using Western blot analysis. Results: The results showed that the decreased survival rate induced by H2O2 could be attributed to the induction of DNA damage and apoptosis accompanied by the increased production of ROS, which was remarkably protected by EEPR. In addition, the loss of H2O2-induced MMPs and ATP contents was significantly attenuated in the presence of EEPR. The inhibitory effect of EEPR on H2O2-induced apoptosis was associated with up-regulation of Bcl-2 and down-regulation of Bax, thus reducing the Bax/Bcl-2 ratio. Conclusions: Our data prove that EEPR protects Chang liver cells against H2O2-induced DNA damage and apoptosis by scavenging ROS and thus suppressing the mitochondrial-dependent apoptosis pathway.