ABSTRACT
OBJECTIVE: To investigate the mitochondrial damage and the possible mechanism in the process of MCF-7 cell apoptosis which induced by quercetin. METHODS: The cell apoptosis model was established with MCF-7 cells induced by quercetin. The morphological characteristics of apoptotic MCF-7 cells were observed by transmission electron microscope. Fluorescent probes DCFH-DA and Fluo-8-AM were used to detect the invaded cells' reactive oxygen species (ROS) and intracellular Ca2+concentration, respectively. The calcium channel blockers of extracellular and intracellular were used to inhibit apoptosis induced by quercetin in MCF-7 cells, the cellular apoptosis rates of which were measured by flow cytometry. Western blot assay was used to detect the expressions of Cyt C. RESULTS: Quercetin can induce MCF-7 cell mitochondria apoptosis. The spherical swelling, mitochondrial crest disappear and the formation of cavity were happened to those cells. Intracellular ROS and Ca2+ increased. The apoptosis induced by quercetin can be inhibit by intracellular calcium blockers ryanodine. After incubation with ryanodine, apoptosis rates fell by 55.4% at 24 h, 55.4% at 48 h and 39.9% at 72 h, respectively. The cell apoptosis induced by quercetin was not inhibited by EDTA. The expression of Cyt C was increased in the cytoplasm but not mitochondria after cultured the MCF-7 cell with EDTA. CONCLUSION: The mitochondrial damage plays an important role in the MCF-7 apoptosis which induced by quercetin, and its possible mechanism may related to the elevated levels of ROS and the release of Ca2+ and Cyt C in the cytoplasm. Meanwhile, Cyt C in the cytosol is potential critical signaling molecular in the process of apoptosis.