超声造影剂微循环显影对家兔缺血性视神经病变血流动力学改变的研究

Hemodynamic changes by ultrasound contrast agents in the microcirculation of rabbits with ischemic optic neuropathy

目的:探讨超声造影剂在家兔眼部睫状循环的显影并研究颈动脉狭窄与前部缺血性视神经病变(anterior ischemic optic neuropathy,AION)的关系。方法:将36只健康雄性家兔随机分为手术组(20只40眼)、假手术组(8只16眼)、空白对照组(8只16眼)。手术组采取家兔颈动脉部分缝合术建立颈动脉狭窄的动物模型,假手术组行颈动脉临时夹闭,空白组不做任何处理。分别于术后3、7、14、21 d和35 d行颈动脉彩色多普勒超声检查、超声造影剂睫状微循环显影与视神经组织病理学分析。结果:手术组家兔造模成功,术后均出现不同程度颈动脉狭窄。3、7、14、21 d和35 d颈动脉内径值分别为(0.74±0.15)、(0.74±0.15)、(0.81±0.20)、(0.88±0.20)mm和(1.05±0.29)mm,较假手术组与空白对照组低,差异无统计学意义(P<0.05)。超声造影剂在睫状动脉显影良好,手术组单个超声微泡移动速度在各时间点分别为(7.10±2.12)、(8.20±2.39)、(8.11±2.24)、(7.46±2.19)mm/s和(10.11±3.14)mm/s,较假手术组及空白对照组低,差异有统计学意义(P<0.05)。光学显微镜下可见手术组视神经纤维排列紊乱,轴突肿胀呈空泡状,细胞质着色浅,炎性细胞浸润。结论:通过超声造影剂微循环显影可观察到颈动脉狭窄的家兔睫状动脉血流速率下降,并出现视神经的组织病理学改变,提示颈动脉狭窄可以引起缺血性视神经病变。

Objective：To investigate ultrasound contrast agents imaging in the ocular posterior ciliary artery and the relationship between carotid artery stenosis and anterior ischemic optic neuropathy. Methods：Totally 36 healthy male rabbits were randomly divided into operation group（20 rabbits,40 eyes）,sham operation group（8 rabbits,16 eyes）and blank control group（8 rabbits,16 eyes）. Operation group received partial carotid suture to establish the rabbit models with carotid artery stenosis,sham operation group received temporary occlusion of carotid artery and blank control group didn’t receive any intervention. Carotid arteries were examed by color Doppler ultrasound and hemodynamic changes of oculor ciliary circulation were detected by ultrasound contrast agent. Histopathological changes of optic nerves on 3,7,14,21,35 d after the surgery were analyzed respectively. Results：Animal models were successfully established and varying degrees of stenosis were showed in operation group. Carotid artery diameters in operation group on 3, 7,14,21,35 d were（0.74 ± 0.15）,（0.74 ± 0.15）,（0.81 ± 0.20）,（0.88 ± 0.20）,（1.05 ± 0.29）mm,lower than those in sham operation group and blank control group（P＆lt;0.05）. Ultrasound contrast agent in the ciliary artery developed well and single microbubble velocity in operation group at each time point were（7.10±2.12）,（8.20±2.39）,（8.11±2.24）,（7.46±2.19）,（10.11±3.14）mm/s,lower than those in sham operation group and blank control group（P＆lt;0.05）. Optic nerve fibers in operation group were disordered with swelling axonal,pale and vacuolar cytoplasm,and inflammatory cell infiltration. Conclusions：Blood flow velocity of posterior ciliary arteries and histopathology changes in optic nerve in rabbits,suggesting that carotid artery stenosis can cause ischemic optic neuropathy.