大鼠实验性慢性高眼压对视网膜神经节细胞的损伤

目的:制作高眼压大鼠模型,观察高眼压对视神经的损害。方法:成年Wistar雄性大鼠65只,烧灼右眼上方2支和外侧1支巩膜上静脉,建立慢性高眼压模型。左眼作为对照眼。对造模成功的,分别于造模后1d,1,2,3,4,6,8,10wk各摘除6只大鼠双眼。在取出眼球前24h,用Fluoro-gold进行视网膜神经节细胞(retinal ganglion cells,RGC)逆行性染色,做视网膜铺片计数RGC,观察不同时段高眼压对RGC的影响。结果:右眼巩膜上静脉烧灼后各时间点造模眼平均眼压分别为42.2±1.8mmHg,37.9±2.3mmHg,36.1±2.0mmHg,33.6±2.2mmHg,32.2±2.4mmHg,30.1±2.0mmHg,30.5±2.1mmHg和27.6±1.3mmHg。术后各时间点的成模率分别为80.0%,76.9%,74.5%,71.7%,63.8%,56.1%,42.9%,41.4%。成模率和成模眼的眼压随时间延长呈下降趋势。实验组和对照组的RGC密度在早期(巩膜上静脉烧灼术后3wk内)没有显著差别。造模后4wk高眼压组RGC密度明显低于对照组(P<0.05),随着时间的推移差别越来越显著。结论:巩膜上静脉烧灼法能诱导出持续的肯定的大鼠慢性高眼压模型,成模眼的眼压和随时间而下降。高眼压持续的时间越长,RGC的损失越多。

Injury of gangliocyte in rat with chronic ocular hypertension

AIM:To investigate the pressure-induced nerve damage in experimental chronic glaucoma model in rat.·METHODS: Sixty-five adult male Wistar rats were rendered for elevation of intraocular pressure (IOP) by cauterizing 3 episcleral veins in the right eyes ,and the left eyes were taken as the control group. 1 day;1 week,2,3,4,6,8,10 weeks after cauterization of episcleral veins,6 rats were sacrificed respectively. Retinal ganglion cells (RGC) retrograde labeling was completed with Fluoro-gold 24 hours before enucleation.The retina wholemount was performed ,and the number of RGCs was counted.·RESULTS: The mean IOP 1 day;1 week,2,3,4,6,8,10 weeks after cauterization of episcleral veins was,42.2±1.8mmHg,37.9±2.3mmHg,36.1±2.0mmHg,33.4±2.1mmHg,32.2±2.4mmHg,30.1±2.0mmHg,30.6±2.2mmHg and 27.6±1.3mmHg,respectively. The success rate of high IOP model was 80.0%,76.9%,74.6%,71.7%,63.8%,56.1%,42.9% and 41.4% 1 day;1,2,3,4,6,8,10 weeks after operation. The IOP and success rate decreased with time. There was no significant difference of RGC density between two groups at early stage (within 3 weeks after operation). At the fourth week,the RGC density in rats with high IOP was lower compared with those with normal IOP. The difference increased with time.·CONCLUSION: Cauterization of episcleral veins induces durative,affirmative intraocular hypertension in rat. The pressure of model decreases with time. The loss of RGC increases with the duration of intraocular hypertension.