Background Oxidative stress is one of the key contributors to cellular senescence and aging in mammals. Quercetin is a kind of bioactive flavonoid widely existing in medicinal plants and food. It has a variety of physiological activities such as antioxidant. Given that hydrogen peroxide (H2O2), as a strong oxidant, can easily diffuse through the cell membrane and cause oxidative damage to cells, the present study is designed to verify the protective effect of quercetin on ovarian granulosa cells under oxidative stress.
Methods Cell viability and toxicity were examined by Cell Counting Kit-8 (CCK-8) and Lactate Dehydrogenase (LDH) assays. Reactive oxygen species (ROS) accumulation was detected by flow cytometry. Glutathione (GSH) level was measured to analyze the oxidation resistance. Cell apoptosis was evaluated by Hoechst 33258 staining, Acridine Orange (AO)/Ethidium Bromide (EB) staining and western blot. The mitochondrial structure was observed under a transmission electron microscope. Mitochondrial membrane integrity was detected by JC-1 staining and western blot.
Results The results of the present study indicated that H2O2 could induce cell damage, promote ROS accumulation, and lead to GSH depletion. Further studies demonstrated that H2O2 resulted in mitochondrial morphological damage and depolarization, which activate caspase3/9 subsequently. However, quercetin could mitigate the damages.
Conclusions Present study found that H2O2 induced oxidative stress and mitochondrial apoptosis of human ovarian granulosa tumor cell line (KGN), which could be attenuated by quercetin.