Chemical and Biomedical Engineering Department, University of South Florida, Tampa, Florida, United States.
Electrical Engineering Department, University of South Florida, Tampa, Florida, United States.
Invest Ophthalmol Vis Sci. 2018 May 1;59(6):2529-2537. doi: 10.1167/iovs.17-22915.
The study aimed to provide a quantitative description of aqueous humor dynamics in healthy rat eyes.
One eye of 26 anesthetized adult Brown-Norway rats was cannulated with a needle connected to a perfusion pump and pressure transducer. Pressure-flow data were measured in live and dead eyes by varying pump rate (constant-flow technique) or by modulating pump duty cycle to hold intraocular pressure (IOP) at set levels (modified constant-pressure technique). Data were fit by the Goldmann equation to estimate conventional outflow facility (C) and unconventional outflow rate (Fun). Parameter estimates were respectively checked by inserting a shunt of similar conductance into the eye and by varying eye hydration methodology.
Rat IOP averaged 14.6 ± 1.9 mm Hg at rest. Pressure-flow data were repeatable and indistinguishable for the two perfusion techniques, yielding C = 0.023 ± 0.002 μL/min/mm Hg and Fun = 0.096 ± 0.024 μL/min. C was similar for live and dead eyes and increased upon shunt insertion by an amount equal to shunt conductance, validating measurement accuracy. At 100% humidity Fun dropped to 0.003 ± 0.030 μL/min. Physiological washout was not observed (-0.35 ± 0.65%/h), and trabecular anatomy looked normal.
Rat aqueous humor dynamics are intermediate in magnitude compared to those in mice and humans, consistent with species differences in eye size. C does not change with time or death. Evaporation complicates measurement of Fun even when eyes are not enucleated. Absence of washout is a notable finding seen only in mouse and human eyes to date.
本研究旨在定量描述健康大鼠眼房水动力学。
对 26 只麻醉成年棕褐色挪威大鼠的一只眼睛进行穿刺，用连接到灌注泵和压力传感器的针进行穿刺。通过改变泵速（恒流技术）或调节泵工作周期以将眼内压（IOP）保持在设定水平（改良恒压技术）来测量活眼和死眼的压力-流量数据。通过 Goldmann 方程拟合数据来估计传统流出系数（C）和非常规流出率（Fun）。通过将类似电导的分流器插入眼睛中和改变眼睛水合作用方法来分别检查参数估计值。
大鼠的 IOP 在休息时平均为 14.6 ± 1.9 mmHg。压力-流量数据对于两种灌注技术是可重复的且不可区分的，得到 C = 0.023 ± 0.002 μL/min/mm Hg 和 Fun = 0.096 ± 0.024 μL/min。活眼和死眼的 C 相似，插入分流器后增加量等于分流器的电导，验证了测量的准确性。在 100%湿度下，Fun 下降至 0.003 ± 0.030 μL/min。未观察到生理冲洗（-0.35 ± 0.65%/h），小梁解剖结构正常。
与小鼠和人类相比，大鼠房水动力学的幅度中等，与眼球大小的物种差异一致。C 不会随时间或死亡而变化。即使不取出眼球，蒸发也会使 Fun 的测量复杂化。到目前为止，仅在小鼠和人眼上观察到冲洗缺失是一个显著的发现。
