Experimental Ophthalmology, Department of Ophthalmology, University Medical Center of the Johannes Gutenberg University Mainz, Germany.
Invest Ophthalmol Vis Sci. 2014 Jan 29;55(1):600-11. doi: 10.1167/iovs.13-12714.
An important, yet not exclusive, aspect of primary open angle glaucoma is elevated intraocular pressure (IOP) profiles within fluctuations and pressure peaks. The study aimed at establishing minimally invasive methods for recurrent IOP elevation in rats to investigate the impact of IOP dynamics and pathomorphologic retinal alterations during and after IOP elevation.
Intraocular pressure was elevated unilaterally in Long Evans rats to a level of ≈35 mm Hg for 1 hour in a total of 30 manipulations within 6 weeks, by using two methods: (1) suction-cup oculopression and (2) loop-adjusted oculopression. Retinal thickness (RT) was measured via optical coherence tomography (OCT), and neuronal survival was analyzed. Additional experiments were performed for "in situ" OCT investigations during exposures to different IOP levels.
A mean IOP exposure of +737.3 ± 9.6 ΔIOP mm Hg for loop adjustment and +188.9 ± 16 ΔIOP mm Hg for suction cup was achieved. Optical coherence tomography examination revealed notable changes of RT between controls, untreated, and treated eyes, and evaluation of neuronal loss showed a significant decrease of retinal ganglion cell (RGC) density in both groups. In situ OCT investigation showed paradoxical retinal distortion and deformation of the optic nerve head toward the eye background.
After accurate IOP elevation with minimally invasive methods, it was possible to detect RGC loss and retinal thinning. While suction cup is capable of simulating accurate arbitrary IOP profiles, loop adjustment enables the detection of pressure-dependent retinal alterations. For the first time, it was feasible to investigate consequences of variable IOP elevation profiles, including pressure peaks, by using real-time live imaging in vivo.
原发性开角型青光眼的一个重要但非排他性方面是眼内压(IOP)波动和压力峰值时升高的眼压谱。本研究旨在建立大鼠复发性眼压升高的微创方法,以研究眼压升高期间和之后眼压动态和病理形态视网膜改变的影响。
在总共 6 周内进行了 30 次操作,通过两种方法将 Long Evans 大鼠的单侧眼内压升高至约 35mmHg 持续 1 小时:(1) 吸盘眼压迫和(2) 环调整眼压迫。通过光学相干断层扫描(OCT)测量视网膜厚度(RT),并分析神经元存活情况。还进行了额外的实验,以在暴露于不同眼压水平期间进行“原位”OCT 研究。
环调整的平均眼压暴露为+737.3±9.6ΔIOPmmHg,吸盘的平均眼压暴露为+188.9±16ΔIOPmmHg。OCT 检查显示 RT 在对照组、未治疗组和治疗组之间有明显变化,神经元丢失评估显示两组的视网膜神经节细胞(RGC)密度均显著下降。原位 OCT 研究显示视网膜扭曲和视盘变形,向眼球背景方向变形。
通过微创方法准确升高眼压后,可以检测到 RGC 丢失和视网膜变薄。虽然吸盘能够模拟准确的任意眼压谱,但环调整能够检测到与压力相关的视网膜改变。首次通过实时活体成像在体内研究了可变眼压升高谱的后果,包括压力峰值。