Morphological and functional changes of mitochondria in apoptotic esophageal carcinoma cells induced by arsenic trioxide

AIM: To demonstrate that mitochondrial morphological andfunctional changes are an important intermediate link in thecourse of apoptosis in esophageal carcinoma cells inducedby As2O3.METHODS: The esophageal carcinoma cell line SHEEC1,established in our laboratory, was cultured in 199 growthmedium, supplemented with 100mL@ L-1 calf serum and3 mol@L-1 As2O3( the same below). After 2, 4, 6, 12, 24 hof drug adding, the SHEEC1 cells were collected for light-and electron-microscopic examination. The mitochondriawere labeled by Rhodamine fluorescence probe and thefluorescence intensity of the mitochondria was measured byflow cytometer and cytofluorimetric analysis. Further, themitochondrial transmembrane potential ( MTP, ΔΨm )change was also calculated.RESULTS: The mitochondrial morphological change afteradding As2O3 could be divided into three stages. In theearly-stage (2-6h) after adding As2O3, an adaptiveproliferation of mitochondria appeared; in the mid-stage (6-12 h ) e degenerative change was observed; and in the late-stage (12-24 h ) the mitochondria swelled with outermembrana broken down and then calls death with apoptoticchanges of nucleus. The functional change of themitochondria indicated by fluorescent intensity, whichreflected the MTP status of mitochondria, was in accordancewith morphological change of the mitochondria. Thefluorescent intensity increased at early-stage, declined inmid-stage and decreased to the lowest in the late@ stage. 24h after As2O3 adding, the cell nucleus showed typicalapoptotic changes.CONCLUSION: Under the inducement of As2O3, the earlyapoptotic changes of SHEEC1 cells were the apparentmorphological and functional changes of mitochondria,afterwards the nucleus changes followed. lt is consideredthat changes of mitochondria are an important intermediatelink in the course of apoptosis of esophageal carcinomacalls induced by As2O3.