Härdig Bjarne Madsen, Persson Hans W, Olsson S Bertil
Department of Cardiology, Clinical Sciences, Lund University, University Hospital, SE - 221 85 Lund, Sweden.
Thromb Res. 2006;117(6):713-20. doi: 10.1016/j.thromres.2005.05.027. Epub 2005 Jul 1.
This study explores the mechanisms of ultrasound-enhanced fibrinolysis by investigating the effects of pre-exposure to pulsed high-frequency, low-energy ultrasound on the fibrinolytic properties of streptokinase.
Fibrinolytic activity was measured as haemoglobin release from blood clots. The fibrinolytic effects of streptokinase and ultrasound separately and in combination were studied by evaluating cumulative percentages of haemoglobin release following 1 h of exposure using two clots, one for intervention and the other concomitantly as control. In particular, the effects of exposure to ultrasound on clot-free streptokinase solution were compared to those of concomitant exposures of streptokinase solution with clot. The exposures were made at a frequency of 1 MHz (10% duty cycle) and at three intensity levels (0.5, 1.0 and 4.0 W/cm2 intensity I(SATA)).
Increased fibrinolysis (31.2%, P=0.028) was observed after concomitant ultrasound exposure of clot and streptokinase solution at 0.5 W/cm2 intensity. Compared to unexposed streptokinase solution, the lytic effect following exposure of streptokinase solution to ultrasound was significantly increased (32.7%, P=0.002). This enhancement effect disappeared at intensity 1 W/cm2, whilst further increase to 4.0 W/cm2 inhibited the lytic effect of streptokinase, both during concomitant exposure (-25.2%, P=0.028) and after pre-exposure of streptokinase solution to ultrasound (-25.4%, P=0.002).
The fibrinolytic property of streptokinase is modulated by exposure to pulsed ultrasound of frequency 1 MHz, being enhanced at low intensity and inhibited at high intensity.
本研究通过调查预先暴露于脉冲高频、低能量超声对链激酶纤维蛋白溶解特性的影响，探索超声增强纤维蛋白溶解的机制。
纤维蛋白溶解活性通过血凝块中血红蛋白释放量来衡量。通过评估使用两块血凝块暴露1小时后血红蛋白释放的累积百分比，分别研究链激酶和超声单独及联合的纤维蛋白溶解作用，一块用于干预，另一块作为对照。特别地，将超声暴露于无凝块链激酶溶液的效果与链激酶溶液与凝块同时暴露的效果进行比较。暴露频率为1兆赫（占空比10%），强度水平为三个（0.5、1.0和4.0瓦/平方厘米强度I（SATA））。
在凝块和链激酶溶液同时以0.5瓦/平方厘米强度暴露于超声后，观察到纤维蛋白溶解增加（31.2%，P = 0.028）。与未暴露的链激酶溶液相比，链激酶溶液暴露于超声后的溶解效果显著增加（32.7%，P = 0.002）。这种增强作用在强度为1瓦/平方厘米时消失，而进一步增加到4.0瓦/平方厘米会抑制链激酶的溶解作用，无论是在同时暴露期间（-25.2%，P = 0.028）还是链激酶溶液预先暴露于超声后（-25.4%，P = 0.002）。
链激酶的纤维蛋白溶解特性受到频率为1兆赫的脉冲超声暴露的调节，在低强度下增强，在高强度下抑制。
