微泡增强的非聚焦超声阻断肝脏血流灌注的超微结构变化

Ultrastructure changes after blocking hepatic perfusion using mlcrobubble-enhanced non-focused ultrasound

目的探讨微泡增强的非聚焦超声阻断肝脏血流对肝脏超微结构的影响。方法18只健康新西兰大白兔建立肝脏创伤模型后，按随机数字表法分为创伤组、超声组、超声微泡增强组（增强组），每组各6只。用定制的非聚焦超声治疗仪对肝左叶创伤区进行辐照5min，观察各组辐照后即刻血流灌注情况，记录峰值强度（PI）。观察各组辐照即刻、24h肝脏组织超微结构的变化。结果创伤组、超声组和增强组的PI值分别为23．1±1．1、23．4±1．3和15．1±2．6，与创伤组比较，超声组差异无统计学意义（P〉0．05），而增强组差异有统计学意义（P〈0．05），超声组与增强组比较差异有统计学意义（P〈0．05）。与创伤组和超声组比较，增强组辐照即刻肝细胞明显水肿，肝窦间隙变小，肝细胞内细胞器排列紊乱、线粒体水肿，汇管区肝小叶间动脉、静脉的内皮细胞以及毛细胆管内皮细胞受损，毛细胆管的微绒毛消失；辐照24h后，肝细胞可见凋亡形态学表现。结论微泡增强的非聚焦超声可减少肝脏的血流灌注，但对肝细胞的超微结构会造成一定的损伤，并可能引起辐照区及周围肝细胞的凋亡。

Objective To investigate the effect of microbubble-enhanced non-focused ultrasound on liver ultrastructure during the treatment of hepatic trauma. Methods The model of hepatic trauma was established in 18 healthy New Zealand rabbits. The subjects were divided into trauma group, ultrasound group and ultrasound-microbubble group according to the random number table, with 6 rabbits each. Thicker region of the left hepatic lobe was treated by custom-made non-focused ultrasound for 5 min. Peak intensity （PI） was used to evaluate the blood reperfusion of the target region after treatment. Liver specimens were performed transmission electron microscope examination immediately and 24 h after treatment to analyze ultrastrueture changes. Results PI ratio in ultrasound-microbubble group （ 15.1 ±2.6 ） was significantly lower than that in trauma group （23.1± 1.1 ） and ultrasound group （23.4± 1.3 ） （P 〈 0.05 ）. But the difference between trauma and ultrasound groups was insignificant （P 〉 0.05 ）. Compared with trauma and ultrasound groups immediately after treatment, hepatic cells in ultrasound- microbubble group had obvious edema, sinusoids thinned, organelles arranged in disorder, mitocbondrial edema was present, endothelia cells of interlobular hepatic artery, interlobular vein and bile canaliculi in the portal area damaged, and microvilli of bile canaliculi disappeared. Hepatic cells showed morphology of apoptosis 24 h after treatment. Conclusion Microbubble-enhanced non-focused ultrasound can be used to make rapid hemostasis by decreasing the blood perfusion, but it causes certain damage to the ultrastructure of hepatic cells and may induce apoptosis in the radiation zone and neighboring cells.