Acute Variations in Retinal Vascular Oxygen Content in a Rabbit Model of Retinal Venous Occlusion

PurposeTo study the variation in intravascular oxygen saturation (oximetry) during an acute retinal vein occlusion (RVO) using hyperspectral computed tomographic spectroscopy based oximetry measurements. MethodsThirty rabbits were dilated and anesthetized for experiments. Baseline oximetry measurements were made using a custom-made hyperspectral computed tomographic imaging spectrometer coupled to a fundus camera. RVO were induced using argon green laser following an intravenous injection of Rose Bengal. RVO induction was confirmed by fluorescein angiography. Retinal oximetry measurements were repeated in arterial and venous branches one hour after RVO induction and up to 4 weeks afterwards. Comparison of retinal oximetry before and after vein occlusion was made using the Student T-test. ResultsOne hour after RVO induction, we observed statistically significant reductions in the intravascular oxygen saturation in temporal retinal arteries (85.1±6.1% vs. 80.6±6.6%; p ConclusionsWe demonstrate, for the first time, acute changes in the intravascular oxygen content of retinal vessels 1 hour after RVO. These changes are reversible upon spontaneous recannulation of retinal vessels. This study demonstrates that hyperspectral computer tomographic spectroscopy based oximetry can detect physiological variations in intravascular retinal oxygen saturation. The study also provides the first qualitative and quantitative evidence of the variation in retinal vascular oxygen content directly attributable to an acute retinal vein occlusion.

研究目的：本研究旨在利用基于高光谱计算机断层扫描光谱的血氧测定（oximetry）技术，探究急性视网膜静脉阻塞（retinal vein occlusion, RVO）发作期间血管内血氧饱和度的变化情况。
实验方法：选取30只家兔进行散瞳与麻醉后开展实验。采用定制化高光谱计算机断层扫描成像光谱仪搭配眼底相机完成基线血氧测定。经静脉注射孟加拉玫瑰红后，使用氩绿激光诱导视网膜静脉阻塞（RVO），并通过荧光素眼底血管造影确认造模成功。在造模后1小时及后续长达4周的时段内，分别对视网膜动脉与静脉分支重复开展血氧测定。采用学生t检验（Student T-test）对静脉阻塞前后的视网膜血氧测定结果进行对比分析。
实验结果：造模后1小时，我们观察到颞侧视网膜动脉的血管内血氧饱和度出现具有统计学意义的降低（85.1±6.1% vs. 80.6±6.6%；p
研究结论：本研究首次证实，急性视网膜静脉阻塞（RVO）发生1小时后，视网膜血管的血管内血氧含量即出现急性变化，此类变化可随视网膜血管自发再通而恢复。本研究证明，基于高光谱计算机断层扫描光谱的血氧测定技术可检测视网膜血管内血氧饱和度的生理性变化。此外，本研究首次为急性视网膜静脉阻塞直接导致的视网膜血管血氧含量变化提供了定性与定量证据。