Objective:To investigate t h e role of mitochondria in sodium butyrate-induced apoptosis of ovarian carcinom a cells in vitro.Methods:Human ovarian epithelial cancer 3AO ce lls were cultured in vitro and treated with sodium butyrate of different concent ration for different time. The characters of apoptosis were assessed through lig ht microscopy and DNA ladder analysis. The morphological changes of mitochondria were detected through electron and epifluorescence microscopy. The functional c hanges of mitochondria and the expression of Bcl-2/Bax protein were analyzed by flow cytometry.Results:As the concentration of sodium butyrate ros e to 4mmol/L, the morphologic characters of apoptosis were found by light micros copy, DNA ladder was observed. Under epifluorescence microscope the fluorescence of the control group was stronger than that of the experimental group. Under el ec tron microscope swelled mitochondria was detected. Flow cytometry analysis sh ow ed mitochondria transmembrane potentials decreased and there were down-regulate of Bcl-2 protein and up-regulate of the Bax protein(P<0.05). Conclusion:Sodium butyrate can induce apoptosis of 3AO cells in a time -dose dependent manner. Mitochondrion may play a key role in the procedure of a poptosis of ovarian cancer cells. Objective: To investigate the role of mitochondria in sodium butyrate-induced apoptosis of ovarian carcinom a cells in vitro. Methods: Human ovarian epithelial cancer 3AO ce lls were cultured in vitro and treated with sodium butyrate of different concent ration for different time. The characters of apoptosis were assessed through lig ht microscopy and DNA ladder analysis. The morphological changes of mitochondria were detected through electron and epifluorescence microscopy. The functional c hanges of mitochondria and the expression of Bcl-2 / Bax protein were analyzed by flow cytometry. Results: Under the concentration of sodium butyrate ros e to 4 mmol / L, the morphologic characters of apoptosis were found by light micros copy, DNA ladder was observed. Under epifluorescence microscope the fluorescence of the control group was stronger than that of the experimental group. ec tron ​​microscope swelled mitochondria was detected. Flow cytometry analysis sh ow ed mitochondria transmembr ane potentials decreased and there were down-regulate of Bcl-2 protein and up-regulate of the Bax protein (P <0.05). Conclusion: Sodium butyrate can induce apoptosis of 3AO cells in a time-dependent dependent manner. Mitochondrion may play a key role in the procedure of a poptosis of ovarian cancer cells.