内皮素对兔视神经乳头微循环的作用

The Effect of Endothelin-1 on Blood Circulation of Rabit Optic-nerver-head

目的 研究玻璃体注射内皮素后对视神经乳头微循环血流灌注的短期影响。方法 取成年白兔16只,对其中8只右眼玻璃体内注入10-6mol／L的内皮素-1 50μl,对其余8只右眼注入等量的载体,分别在用药前、注射后1 d、3 d、5 d和1周时用HRF(heidelberg retinal flowmetry)和HRA(heidelberg retina angiography)测量视神经乳头处的血流量和视网膜循环时间。结果 兔视乳头的血流量在给药前为294.7±68.7,给药后1 d为137.9±26.6(P<0.01),给药后3 d为198.6±24(P<0.05),第5 d和第7 d分别为274.81±65.8、273.5±44.5。视网膜循环时间在给药前为5.9±0.4 s,给药后1 d为13.9±2.7 s(P<0.01),第3 d-7 d分别为7.1±1.0 s、6.4±0.8 s、5.9±0.3 s。而药物载体眼视神经乳头血流和视网膜循环时间在给药前后均无显著性差别(P>0.05)。结论 向兔眼玻璃体内注射0.25μg内皮素后,视神经乳头在3 d内维持持续的低灌注状态。

Objective To investigate the short-term effect of endothelin-1 on blood circulation of optic nerve head. Method Eight white rabbits were injected 50 microlitre endothelin-1 intravitreously, and the vehicle was injected into the another eight eyes. The blood irrigation of the optic nerve head was evaluated by laser doppler flowmetry before the injection and one day, three days, five days and one week after injection respectively, and the circulation time of retina was measured by Heidelberg retina angiography simultaneously. Result The blood irrigation of optic head was decreased dramatically from 294.7±68.7 to 137.9±26.6 (P<0.01) one day after injection of endothelin-1,198. 6±24 (P<0.05) at the third day, 274.81±65.8 at the fifth day and 273. 5±44.5 at the seventh day.The circulation time of retina was increased from 5.9±0.4s to 13. 9±2.7s( P<0.01) one day after injection, and the time was 7.1±1.0s, 6. 4±0.8s, 5.9±0.3 s respectively from the third to seventh day. In the control group, the blood irrigation of optic nerve head and circulation time of retina after vehicle injection there was no difference compared to that before vehicle injection. Conclusion The injection of endothelin at a dose of about 0.25 μg intravitreously can reduce blood irrigation of rabbit optic head for three days.