玻璃体腔注射内皮素-1诱导猫视盘慢性缺血的实验研究

目的猫眼玻璃体腔注射内皮素-1（endothelin-1，ET-1）诱导视盘慢性缺血动物模型，研究慢性缺血对视神经的影响。方法将13只猫随机分为A组7只和B组6只。右眼为实验眼，左眼为对照眼。实验开始时（术前）行眼部检查和眼压测量，海德堡共焦扫描激光多普勒视网膜地形图（heidelberg retina tomography，HRT）分析视盘形态，海德堡共焦扫描激光多普勒视网膜血流分析仪（heidelberg retina flowmeter，HRF）分析视盘筛板微循环。实验眼注入10μL ET-1溶液，A组浓度为10^-6mol／L，B组为10^-5mol／L，对照眼注入10μL相应赋形剂。每周注射2次，连续4周。每次注药前后均行眼部检查、眼压测量。实验结束后检查同术前。取视神经标本进行视神经轴突计数。结果B组实验眼注药前后眼压与术前眼压比较，部分检测点差异有统计学意义；实验眼术后视盘筛板血流量降低33．80％，血流速降低57．73％，红细胞移动速率降低57．70％；术后实验眼较对照眼视神经轴突数减少10．70％。A组中实验眼和对照眼术前、术后各研究参数差异均无统计学意义。结论猫眼玻璃体腔多次微量注射10^-5mol／LET-1可诱导视盘缺血，损害视神经。

Experimental study of chronic optic disk ischemia induced by injecting endothelin-1 into the posterior vitreous in cat

Objective To investigate the effect of chronic ischemia induced by injecting endothelin-1（ET-1）into the posterior vitreous on optic nerve in cat. Methods Thirteen cats were randomly divided into 2 groups, 7 in group A and 6 in group B. The right eyes were defined as the experimental eyes and the left ones as control eyes. Before operation,all the cats received eye examination, intraocular pressure （IOP） measurement, analysis of optic disk configuration u- sing heidelberg retina tomography（HRT） and analysis of the microcirculation in optic disk lamina cribrosa using heidel- berg retina flowmeter（HRF）. All the experimental eyes received an injection of 10 μL ET-1 solution （group A 10^-6mol/L,group B 10^-5 mol/L） into the posterior vitreous twice a week for a consecutive 4 weeks and the control eyes received 10^μL of corresponding excipient. Before and after every injection all the cats received eye examination and IOP measurement. Two months later, all the cats received the same examination as preoperatively, and then the optic nerve specimens were cut off for optic nerve axon counting. Results In group B, compared with the baseline, some of the IOPs in the experimental eyes were statistically lower before and after the injection. The postoperative microcirculation parameters of lamina cribrosa in experimental eyes of group B were reduced compared with the baseline, with the blood flow reduced by 33.80% ,the blood flow rate reduced by 57.73% and the migration rate of red blood cells reduced by 57.70%. The postoperative axons of the experimental eyes were reduced by 10.70% compared with the baseline. In group A, there was no difference in the observed parameters between the experimental and control eyes pre-and postoperatively. Conclusions Multiple injection of 10^-5 mol/L ET-1 into the cats＇ vitreous could induce optic disk ischemia resulting in optic nerve damage.