脉冲型及连续型聚焦超声在诱导胰腺癌细胞凋亡中的作用比较

Background：The incidence and mortality rate of pancreatic cancer have increased dramatically in China over recent decades．Focused ultrasound(FU)has been somewhat successfuI in treating panereatic cancer．The purpose of this study was to investigate apoptosis in pancreatic cancer cells induced by FU． Methods:Suspension of human pancreatic carcinoma cell line PaTu 8988t was radiated by FU,using five doses with different radiation parameters and patterns,including one blank control．Temperature increase of the cell suspension was monitored．Cell apoptosis and death after FU radiation was observed using fluorescence microscopy and was tested by flow cytometer at 3,6,12,24and 48 hours after ultrasound radiation． Results:The maximum cell suspension temperatures following five radiation doses were 28℃,(42.20±2.17)℃,(50.80±0.84)℃，(55.80±2.17)℃,and(65.20±3.11)℃;differences between the doses were statistically significant(P<0.05).The apoptosis rate peaked at 24 hours after radiation at(0.56±0.15)%,(1.28±0.16)%,(1.84±0.29)%,(5.74±1.15)%and(2.00±0.84)%for the five doses;differernce between the doses were significant(P<0.05).Between doses 1-4，cell apoptosis rates increased as the Tmax increased．In dose 5，as the Tmax was above 60℃,the apoptosis rate decreased． Conclusion:Sub-threshold thermal exposures of FU radiation with a continuous radiation pattern could result in higher percentage of apoptosed cells．