Effects of cyclic intraocular pressure on conventional outflow
Effects of cyclic intraocular pressure on conventional outflow
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DOI：
10.1167/iovs.07-0863
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发表时间：
2008-01-01
影响因子：
4.4
通讯作者：
Stamer, W. Daniel
中科院分区：
文献类型：
--
作者：
Ramos, Renata F.;Stamer, W. Daniel
目的。在体内，生物力学应力在组织生理和病理中起着重要作用，影响着细胞和组织的行为。尽管常规流出组织不断暴露于眼压的动态变化中，但此类生物力学应激源对流出功能的影响尚未得到分析。本研究的目的是确定眼脉冲对灌注前节常规流出设施的影响。采用前段灌注模型研究眼搏动对人、猪流出设施的影响。为了确定人体前节段的组织活力，使用了三种互补技术（灌注后形态学和流出组织的细胞密度加上随灌注时间的角膜中央厚度测量）。在猪（-29.96% +/- 6.56;P = 0.009）和人（-27.65% +/- 8.26;P = 0.010）灌注前段中，流出设施一致减少。在灌注后组织学评估（P = 0.227）或角膜中央厚度随时间的变化（P = 0.289）方面，活力数据显示对照组和实验前节段之间无显著差异。相比之下，实验（周期脉冲）前段小梁网的细胞数量（333.86 +/- 22.15核/视场）大于对照组（290.47 +/- 17.60,P = 0.05）。循环脉冲前节段流出设施减少不是细胞或组织损伤的功能，而是常规流出组织对生物力学刺激的主动反应。事实上，观察到暴露于循环应力下的组织中细胞增多，表明机械应力对器官培养中的流出细胞有生理上的益处。
PURPOSE. In vivo, biomechanical stress plays an important role in tissue physiology and pathology, affecting cell and tissue behavior. Even though conventional outflow tissues are constantly exposed to dynamic changes in intraocular pressure, effects of such biomechanical stressors on outflow function have not been analyzed. The purpose of the present study was to determine the effect(s) of ocular pulse on conventional outflow facility in perfused anterior segments.METHODS. The anterior segment perfusion model was used to investigate the impact of ocular pulsation on human and porcine outflow facility. To determine tissue viability of human anterior segments, three complementary techniques (postperfusion morphology and cell density of outflow tissues plus central corneal thickness measurements over time of perfusion) were used.RESULTS. A consistent decrease in outflow facility was observed in response to cyclic intraocular pressure in both porcine (-29.96% +/- 6.56; P = 0.009) and human (-27.65% +/- 8.26; P = 0.010) perfused anterior segments. Viability data showed no significant difference between control and experimental anterior segments, with respect to postperfusion histologic evaluations (P = 0.227) or change in central corneal thickness over time (P = 0.289). In contrast, the cellularity of the trabecular meshwork in experimental (cyclically pulsed) anterior segments (333.86 +/- 22.15 nuclei/ field of view) was greater than in the control eyes (290.47 +/- 17.60, P = 0.05).CONCLUSIONS. Decreased outflow facility in cyclically pulsed anterior segments is not a function of cell or tissue damage, but rather is an active response of the conventional outflow tissues to a biomechanical stimulus. In fact, the observation of increased cellularity in tissues exposed to cyclic stress suggests a physiological benefit of mechanical stress to outflow cells in organ culture.