Miller D L, Thomas R M
Biology and Chemistry Department, Battelle Pacific Northwest Laboratories, Richland, WA 99352.
Ultrasound Med Biol. 1993;19(1):83-90. doi: 10.1016/0301-5629(93)90021-f.
Biological effects of in vitro ultrasonic exposure may result from mechanical and from sonochemical mechanisms related to ultrasonic cavitation. Mechanical cell lysis by 1.61 MHz ultrasonic cavitation was assessed in a rotating tube exposure system by hemolysis measurements. Free radical generation was assessed by the terephthalic acid dosimeter, calibrated by gamma-ray dosage. Sonochemical production was assessed by measuring residual hydrogen peroxide using the sensitive isoluminol method. Exposure conditions were similar for all tests, except longer durations were needed for the free radical and hydrogen peroxide tests. The sonochemical mechanisms were relatively more important for increasing intensity, and increasing temperature. Increasing rotation speed or bubbling with argon before exposure enhanced all cavitation activity. Stopping the rotation reduced all cavitation activity. Burst-mode ultrasound (10.5 microseconds bursts, 1:1 or 1:3 duty cycle) reduced cavitation activity, but gave relatively greater sonochemical activity under some conditions. These results indicate that the mechanical and sonochemical mechanisms can be separately favored to some extent by varying exposure conditions. The observed trends should be helpful for selecting exposure conditions favorable for studying bioeffects of the sonochemical mechanism.
体外超声暴露的生物学效应可能源于与超声空化相关的机械机制和声化学机制。在旋转管暴露系统中，通过溶血测量评估了1.61兆赫超声空化引起的机械性细胞裂解。通过用γ射线剂量校准的对苯二甲酸剂量计评估自由基的产生。使用灵敏的异鲁米诺方法通过测量残余过氧化氢来评估声化学产物。除自由基和过氧化氢测试需要更长的持续时间外，所有测试的暴露条件均相似。对于增加强度和升高温度而言，声化学机制相对更为重要。增加转速或在暴露前用氩气鼓泡可增强所有空化活性。停止旋转会降低所有空化活性。脉冲模式超声（10.5微秒脉冲，1:1或1:3占空比）会降低空化活性，但在某些条件下会产生相对更大的声化学活性。这些结果表明，通过改变暴露条件，在一定程度上可以分别促进机械机制和声化学机制。观察到的趋势应有助于选择有利于研究声化学机制生物效应的暴露条件。
