Yu D Y, Cringle S J, Alder V A
Lions Eye Institute, Nedlands, Australia.
Invest Ophthalmol Vis Sci. 1990 Dec;31(12):2493-9.
The effect of graded systemic hyperoxia on vitreal PO2 distribution has been determined for the rat eye. Oxygen tension profiles were measured, using oxygen-sensitive microelectrodes, as a function of distance from the internal limiting membrane as the inspired oxygen percentage was increased in 10% steps from 20-100%. Depending on the original touching location of the microelectrode on the retina, there could be substantial PO2 gradients within 500 microns of the retina; at greater distances vitreal PO2 was constant and a function of the inspired oxygen percentage. Whatever the location of the microelectrode in the vitreous, PO2 rose with increasing hyperoxia. The relationship between vitreal PO2 and inspired oxygen was nonlinear with a central relatively flat region between 50-80% inspired oxygen. The ratio between vitreal PO2 during 100% O2 breathing and air breathing was 3.42 +/- 1.08 (standard deviation, n = 7). Possible explanations for the plateau region are the maintenance of a relatively constant PO2 by vascular autoregulation and/or the buffering of capillary PO2 by hemoglobin. The rat eye, therefore, responds to hyperoxia similarly to that of the cat and monkey but differs from that of the miniature pig where there is no rise in preretinal PO2 during hyperoxia.
已确定分级全身高氧对大鼠眼玻璃体内氧分压（PO2）分布的影响。使用氧敏感微电极测量氧分压曲线，该曲线是随着吸入氧百分比从20%至100%以10%的步长增加时，距内界膜距离的函数。根据微电极最初在视网膜上的接触位置，在视网膜500微米范围内可能存在显著的PO2梯度；在更大距离处，玻璃体内PO2是恒定的，并且是吸入氧百分比的函数。无论微电极在玻璃体内的位置如何，PO2都随着高氧程度的增加而升高。玻璃体内PO2与吸入氧之间的关系是非线性的，在吸入氧50%至80%之间有一个相对平坦的中心区域。在100%氧气呼吸和空气呼吸期间，玻璃体内PO2的比值为3.42±1.08（标准差，n = 7）。高原区域的可能解释是通过血管自动调节维持相对恒定的PO2和/或血红蛋白对毛细血管PO2的缓冲作用。因此，大鼠眼对高氧的反应与猫和猴相似，但与小型猪不同，小型猪在高氧期间视网膜前PO2没有升高。
