Moore C G, Johnson E C, Morrison J C
Kenneth C. Swan Ocular Neurobiology Laboratory, Oregon Health Sciences University, Portland 97201-4197, USA.
Curr Eye Res. 1996 Feb;15(2):185-91. doi: 10.3109/02713689608997412.
To define the characteristics of the diurnal variation of intraocular pressure (IOP) in eyes of awake rats, ten male brown Norway rats were entrained to a 12-hour light:12-hour dark (12L:12D) lighting schedule and were conditioned to IOP measurement with the TonoPen XL tonometer while awake, using only 0.5% proparacaine HCl anesthesia. The IOP measurements were performed in 4 experiments: Preliminary-IOP was measured at 6-hour intervals in both eyes of each animal, to determine correlation between right and left eyes; Light:Dark-lighting remained the same as in the preliminary experiment, but the measurement schedule was altered so that measurements were obtained at 4-hour intervals in alternating eyes, over two 24-hour light cycles; Dark:Dark-animals were placed in constant dark (0L:24D) and, after 72 h, measurements were obtained at 4-hour intervals in alternating eyes. Animals were then re-entrained to the previous 12L:12D schedule for 7 days, after which they were returned to constant dark and the experiment was repeated; and Dark:Light-animals were entrained to a reversed light:dark cycle (12D:12L) for 28 days, after which measurements were obtained in the same fashion as in the Light:Dark experiment. Close agreement was found between right- and left-eye IOPs. Animals on a 12L:12D schedule exhibited lowest IOP while the lights were on (19.3 +/- 1.9 mm Hg), and highest (31.3 +/- 1.3 mm Hg) while the lights were off. Pressure changes anticipated the change from light to dark and dark to light. This pattern persisted in constant dark, and was reversed when the cycle was changed to 12D:12L. Brown Norway rats possess a regular rhythm of IOP that is entrained by the cycle of light and dark, and persistence of this rhythm in constant dark establishes it as a circadian rhythm. Furthermore, our results indicate that reliable and physiologically meaningful IOP measurements can be obtained in awake rats using the TonoPen XL tonometer.
为了确定清醒大鼠眼内压（IOP）的昼夜变化特征，将10只雄性挪威棕色大鼠置于12小时光照：12小时黑暗（12L:12D）的光照周期中，并在清醒状态下使用仅0.5%盐酸丙美卡因麻醉，用TonoPen XL眼压计对其进行眼压测量训练。眼压测量在4个实验中进行：预实验——每只动物的双眼每隔6小时测量一次眼压，以确定左右眼之间的相关性；光照：黑暗——光照条件与预实验相同，但测量时间表改变，以便在两个24小时光照周期内，每隔4小时交替测量一只眼睛的眼压；黑暗：黑暗——将动物置于持续黑暗（0L:24D）环境中，72小时后，每隔4小时交替测量一只眼睛的眼压。然后将动物重新置于先前的12L:12D光照周期7天，之后再放回持续黑暗环境中并重复实验；黑暗：光照——将动物置于反向光照：黑暗周期（12D:12L）28天，之后以与光照：黑暗实验相同的方式进行测量。发现左右眼眼压高度一致。处于12L:12D光照周期的动物在光照时眼压最低（19.3±1.9毫米汞柱），在黑暗时眼压最高（31.3±1.3毫米汞柱）。眼压变化先于光照与黑暗的转换。这种模式在持续黑暗中持续存在，当周期改为12D:12L时则相反。挪威棕色大鼠具有由明暗周期调节的规律眼压节律，且这种节律在持续黑暗中持续存在，证明其为昼夜节律。此外，我们的结果表明，使用TonoPen XL眼压计可以在清醒大鼠中获得可靠且具有生理意义的眼压测量值。
