不同声强经颅多普勒对兔大脑中动脉组织学的影响

Histology effect of different TCD power on rabbit middle cerebral artery

目的观察不同声强的TCD连续照射兔大脑中动脉2h对血管组织学的影响。方法40只新西兰白兔随机分为四组，每组10只：RV-1组（0mW／cm^2）、RV-2组（70mW／cm^2）、RV-3组（420mW／cm2）、RV-4组（720mW／cm^2）。应用TCD经兔眼窗连续照射2h后，透射电镜观察大脑中动脉的变化。结果RV-1组：血管内皮细胞正常，内皮间紧密连接致密。RV-2组：内皮细胞下大的空泡形成，考虑为内皮下的水肿，内皮细胞胞质内线粒体空泡变性，内质网扩张脱颗粒，细胞间紧密连接区呈毛絮状。RV-3组：内皮细胞有灶性脱落，部分未脱落区细胞内膜结构变性，胞质内线粒体空泡变性，粗面内质网脱颗粒扩张，细胞连接部分区域可见相邻细胞膜间有轻度间隙，部分区域毛絮状。RV-4组：内皮细胞弥漫性改变脱落，细胞胞质内粗面内质网病理性扩张，呈囊泡状脱颗粒，线粒体空泡变性，相邻细胞间可见明显的间隙，细胞膜呈灶性溶解。结论TCD连续照射兔大脑中动脉2h，声强越大对大脑中动脉内皮细胞及紧密连接的破坏越大。

Objective To observe the histology effect of different transcranial Doppler ultrasound （TCD） power on rabbit middle cerebral artery. Methods 40 rabbits were divided randomly into4 groups： RV-I（0 mW/cm2）, RV-2（70 mW/cm2）, RV-3（420 mW/cm2）, RV-4（720 mW/cm2 ）. The changes of middle cerebral artery were observed under transmission electron microscope after 2 - hour TCD monitoring. Results RV - l： vascular endothelial cells were normal. Tight junctions of endodermis were compact. RV - 2： mitoehondria of endothelial cells were vacuolar degeneration. Endoplasmic reticulum expanded and degranulated. Tight junction of endodermis showed floc. RV - 3 ： focal loss of endothelial cells, structure degeneration of other intracellular membrane and vacuolar degeneration of mitochondria were observed. Rough endoplasmic reticulom expanded and degranulated. Light gaps appeared in tight junctions of endodennis. RV -4： endothelial cells lose diffusely. Pathological expansion and vacuolar degranula｜ion of rough endoplasmic retieulum were detected. Mitoehondria vacuolar degenerated and there were larger gaps in tight junction of endodermis. Cellular membrane dissolved partly. Conclusion The more TCD power was used during monitoring rabbit middle eerebral artery continuously for 2 hours, the more seriously endothelial cells and tight junctions were damaged.