Forýtková L, Hrazdira I, Mornstein V
Department of Biophysics, Medical Faculty, Masaryk University, Brno, Czech Republic.
Ultrasound Med Biol. 1995;21(4):585-92. doi: 10.1016/0301-5629(94)00140-9.
The objective of this study was to consider the influence of continuous-wave (CW) ultrasound (800 kHz) on DNA synthesis in Ehrlich ascitic tumor cells in vitro. The 10-min irradiation was carried out in rotating polyethylene tubes (5 rpm). Incorporation of 3H-thymidine was employed to detect DNA synthesis. Replication and unscheduled (repair) DNA synthesis were distinguished by means of hydroxyurea treatment before insonation. It was established that the use of 0.5 W/cm2 and 1.0 W/cm2 (ISA) CW ultrasound interfered with DNA synthesis showing up as inhibition. The inhibition became most noticeable when starting insonation in a sample cooled to 5 degrees C. During insonation, the sample temperature was allowed to increase to the ambient (water bath) temperature of 37 degrees C. However, at an ultrasound intensity (SA) of 0.1 W/cm2 such inhibition was not proven, but a moderate stimulation of DNA synthesis was demonstrated. Changes in DNA synthesis after insonation were found to be transient because of a lack of stimulatory and/or inhibitory ultrasound effects after 1-h incubation at 37 degrees C. In our experimental conditions no effects on DNA synthesis due to the effects of the insonated medium on the cells were discernible. No statistically significant changes in unscheduled DNA synthesis were observed. Possible action mechanisms are discussed.
本研究的目的是探讨连续波（CW）超声（800kHz）对体外培养的艾氏腹水瘤细胞DNA合成的影响。在旋转的聚乙烯管（5转/分钟）中进行10分钟的照射。采用掺入3H-胸腺嘧啶核苷来检测DNA合成。在超声照射前通过羟基脲处理区分复制性和非程序性（修复性）DNA合成。结果表明，使用0.5W/cm2和1.0W/cm2（ISA）的连续波超声会干扰DNA合成，表现为抑制作用。当在冷却至5摄氏度的样品中开始超声照射时，抑制作用最为明显。在超声照射过程中，样品温度会升至环境（水浴）温度37摄氏度。然而，在0.1W/cm2的超声强度（SA）下，未证实有这种抑制作用，但显示出对DNA合成有适度的刺激作用。超声照射后DNA合成的变化是短暂的，因为在37摄氏度孵育1小时后没有刺激和/或抑制性超声效应。在我们的实验条件下，未观察到超声处理过的培养基对细胞的作用导致DNA合成有明显影响。未观察到非程序性DNA合成有统计学上的显著变化。文中讨论了可能的作用机制。
