A study on the mechanism of inducing apoptosis of Tca8113 cells by means of ultrasound hyperthermia

PURPOSE: To investigate the mechanism of apoptosis in Tca8113 cells induced by ultrasound hyperthermia by detecting changes in related index. METHODS: Tca8113 cells were treated in vitro by ultrasound hyperthermia in different heating temperatures (38 degrees C to 44 degrees C,10 minutes) and heating times (42 degrees C,10 to 60 minutes), and then the dynamic changes of early apoptosis and secondary necrosis treated by 42 degrees C for 10 minutes were assayed to detect deltapsim and Caspase-3 levels of different groups by flow cytometry (FCM). The means of each group were compared by ANOVA with SAS6.12 software package. RESULTS: After heated by ultrasound in 42 degrees C for 10 minutes, the early apoptosis of Tca8113 was detected. The apoptosis index reached its highest level at the 6th to 8th hour, then decreased rapidly and maintained in a lower level after 12 hours. The level of secondary necrosis increased with the level of early apoptosis, but kept in a higher level until the 10th hour, the level of secondary necrosis correlated with that of the early apoptosis (r = 0.7909, P = 0.0064). The fraction of cells with low mitochondria membrane potential and increased activity of Caspase-3 were detected either in the heating-temperature grads group or in the heating-time grads group, which showed significant relationship between thetwo apoptosis related index (r = 0.89189, P = 0.0029 in the heating-temperature grads group; r = 0.9679, P = 0.0003 in the heating-time grads group). CONCLUSIONS: Tca8113 cells developed apoptosis after heated by ultrasound hyperthermia along with deltapsim level decreasing and Caspase-3 activity increasing. Ultrasound hyperthermia induces apoptosis of Tca8113 cells by the mitochondrum-Caspase pathway.