Spatial Variations in Vitreous Oxygen Consumption.
Spatial Variations in Vitreous Oxygen Consumption.
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DOI：
10.1371/journal.pone.0149961
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发表时间：
2016
期刊：
影响因子：
3.7
通讯作者：
Humayun M
中科院分区：
文献类型：
--
作者：
Murali K;Kang D;Nazari H;Scianmarello N;Cadenas E;Tai YC;Kashani A;Humayun M
我们研究了猪眼摘除后玻璃体耗氧量的空间变化。制造了一种定制的氧源，可以定位在玻璃体腔的中部或后部，并使用商业上可以买到的探头测量了稳态玻璃体氧分压随距离的变化。使用从猪眼睛采集的玻璃体，通过测量氧压力随时间的变化来估计体外抗坏血酸氧化的反应速率常数。用分光光度法测定玻璃体中、后段的抗坏血酸。当氧源被放置在玻璃体中部(N=6)或玻璃体后部(N=6)时，与没有氧气源的对照实验相比，我们测量到玻璃体氧分压随距离的变化有统计学意义的降低(玻璃体中部P<；0.005，玻璃体后所有距离P<；0.018)。在距氧源2 mm和3 mm处，玻璃体中部和玻璃体后部的氧分压变化有显著差异(p<；0.001)。我们还发现，与玻璃体后段相比，玻璃体中部的抗坏血酸浓度显著降低(p=0.02)。测定了抗坏血酸氧化的反应速率常数k=1.61M-1s-1±0.708 M-1s-1(SE)，该反应符合二级速率方程。我们的数据显示，与玻璃体中部相比，玻璃体后部的玻璃体耗氧量更高。我们还显示了玻璃体抗坏血酸浓度的空间差异。
We investigated the spatial variation of vitreous oxygen consumption in enucleated porcine eyes. A custom made oxygen source was fabricated that could be localized to either the mid or posterior vitreous cavity and steady state vitreous oxygen tension was measured as a function of distance from the source using a commercially available probe. The reaction rate constant of ascorbate oxidation was estimated ex vivo by measuring the change in oxygen tension over time using vitreous harvested from porcine eyes. Vitreous ascorbate from mid and posterior vitreous was measured spectrophotometrically. When the oxygen source was placed in either the mid-vitreous (N = 6) or the posterior vitreous (N = 6), we measured a statistically significant decrease in vitreous oxygen tension as a function of distance from the oxygen source when compared to control experiments without an oxygen source; (p<0.005 for mid-vitreous and p<0.018 for posterior vitreous at all distances). The mid-vitreous oxygen tension change was significantly different from the posterior vitreous oxygen tension change at 2 and 3mm distances from the respective oxygen source (p<0.001). We also found a statistically significant lower concentration of ascorbate in the mid-vitreous as compared to posterior vitreous (p = 0.02). We determined the reaction rate constant, k = 1.61 M-1s-1 ± 0.708 M-1s-1 (SE), of the oxidation of ascorbate which was modeled following a second order rate equation. Our data demonstrates that vitreous oxygen consumption is higher in the posterior vitreous compared to the mid-vitreous. We also show spatial variations in vitreous ascorbate concentration.