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

Abstract:

Objective：To investigate ultrasound contrast agents imaging in the ocular posterior ciliary artery and the relationship be－tween 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. Histopathologi－cal 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 opera－tion group and blank control group（P<0.05）. Ultrasound contrast agent in the ciliary artery developed well and single microbubble ve－locity 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<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 neuropa－thy.