Ivone Mariantonietta, Pappalettere Carmine, Watanabe Akiko, Tachibana Katsuro
Dipartimento di Meccanica, Matematica e Management, Politecnico di Bari, Viale Japigia 182, 70126 Bari, Italy.
Department of Anatomy, Fukuoka University, School of Medicine, 7-45-1 Nanakuma, Fukuoka, 814-0180 Japan.
J Ultrasound. 2016 Apr 4;19(3):167-74. doi: 10.1007/s40477-016-0199-0. eCollection 2016 Sep.
This study will analyze the mechanical effects (immediate lysis) and biological effects (cell survival, apoptosis, cell cycle) on U937 cells subjected to different sonication conditions with increasing and decreasing frequencies and burst rate (number of burst of a repeating signal in a specific time unit), in order to determine the best conditions of sonication to produce high mortality, apoptosis and inhibition of hyperproliferation.
Cells are been stressed by pulse wave ultrasounds with increasing and decreasing frequencies between 400 and 620 kHz, at burst rates of 0.5, 10, 50 Hz and 50 % duty cycle (percentage of one period in which a signal is active), ultrasound intensities (spatial average-temporal peak) 0.045 and 0.09 W/cm(2). The sonication durations were 90 and 180 s.
The decreasing mode was found to be better than the increasing mode for 10 and 50 Hz burst rates, while at 0.5 Hz the increasing mode gave better results for the time of 180 s. For 10 Hz burst rate, decreasing frequency, 180 s, 0.09 W/cm(2), 20 % survival rate was found; after 6-h incubation, cells showed 13 % of early apoptosis and 11 % of late apoptosis. For these conditions of sonication, the hyperproliferation of cells was inhibited.
Survival rate decreases for increasing intensity and duration with each burst rate. The best performance is decreasing mode in a range between 620 and 400 kHz, duty cycle 50 %, burst rate 10 Hz. In these conditions after 180 s duration, the average survival rate is 20 %, the survived cells manifest apoptosis after 6-h incubation and hyperproliferation is prevented. The results seem to lead toward a non-invasive and effective purging of leukemic cells.
本研究将分析在不同超声处理条件下（频率递增和递减以及脉冲重复率，即特定时间单位内重复信号的脉冲数）对U937细胞产生的机械效应（即时溶解）和生物学效应（细胞存活、凋亡、细胞周期），以确定产生高死亡率、凋亡和抑制过度增殖的最佳超声处理条件。
用频率在400至620kHz之间递增和递减的脉冲波超声对细胞进行处理，脉冲重复率为0.5、10、50Hz，占空比为50%（信号活跃的一个周期的百分比），超声强度（空间平均 - 时间峰值）为0.045和0.09W/cm²。超声处理持续时间为90和180秒。
对于10和50Hz的脉冲重复率，发现递减模式优于递增模式，而在0.5Hz时，递增模式在180秒时效果更好。对于10Hz脉冲重复率、递减频率、180秒、0.09W/cm²的条件，发现存活率为20%；孵育6小时后，细胞显示13%的早期凋亡和11%的晚期凋亡。在这些超声处理条件下，细胞的过度增殖受到抑制。
随着每个脉冲重复率下强度和持续时间的增加，存活率降低。最佳性能是在620至400kHz之间、占空比50%、脉冲重复率10Hz的递减模式。在这些条件下，持续180秒后，平均存活率为20%，存活细胞在孵育6小时后出现凋亡，并且过度增殖得到预防。这些结果似乎朝着白血病细胞的非侵入性有效清除方向发展。
