Department of Neurology, Comprehensive Stroke Center, University of Alabama Hospital, 619 19th Street South, Birmingham, AL, 35249, USA,
Transl Stroke Res. 2011 Sep;2(3):376-81. doi: 10.1007/s12975-011-0080-6. Epub 2011 Apr 21.
It is largely unknown whether prolonged insonation with ultrasound impacts the ischemic brain tissue by itself. Our goal was to evaluate safety and the effect of high-frequency ultrasound on infarct volume in rats. Thirty-two Long-Evans rats with permanent middle cerebral and carotid artery occlusions received either 2-MHz ultrasound at two levels of insonation power (128 or 10 mW) or no ultrasound (controls). We measured cerebral hemorrhage, indirect and direct infarct volume as well as edema volume at 24 h. No cerebral hemorrhages were detected in all animals. Exposure to low-power (10 mW) ultrasound resulted in a significantly decreased indirect infarct volume (p = 0.0039), direct infarct volume (p = 0.0031), and brain edema volume (p = 0.01) compared with controls. High-power (128 mW) ultrasound had no significant effects. An additional experiment with India ink showed a greater intravascular penetration of dye into ischemic tissues exposed to low-power ultrasound. Insonation with high-frequency, low-power ultrasound reduces ischemic brain damage in rat. Its effect on edema reduction and possible promotion of microcirculation could be used to facilitate drug and nutrient delivery to ischemic areas.
目前尚不清楚长时间的超声照射是否会对缺血脑组织造成影响。我们的目的是评估高频超声对大鼠梗死体积的安全性和影响。32 只永久性大脑中动脉和颈内动脉闭塞的 Long-Evans 大鼠接受了两种超声功率（128 或 10 mW）的 2 MHz 超声或无超声（对照组）照射。我们在 24 小时时测量了脑出血、间接和直接梗死体积以及水肿体积。所有动物均未检测到脑出血。与对照组相比，低功率（10 mW）超声照射可显著降低间接梗死体积（p = 0.0039）、直接梗死体积（p = 0.0031）和脑水肿体积（p = 0.01）。高功率（128 mW）超声照射没有显著影响。一项额外的印度墨水实验显示，低功率超声照射下的缺血组织内的染料血管内渗透更大。高频、低功率超声照射可减轻大鼠缺血性脑损伤。其对减轻水肿和可能促进微循环的作用可用于促进药物和营养物质输送到缺血区域。
