Microtubule contribution to the reflectance of the retinal nerve fiber layer
Microtubule contribution to the reflectance of the retinal nerve fiber layer
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DOI：
10.1167/iovs.06-0451
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发表时间：
2006-12-01
影响因子：
4.4
通讯作者：
Cavuoto, Lora N.
中科院分区：
文献类型：
--
作者：
Huang, Xiang-Run;Knighton, Robert W.;Cavuoto, Lora N.
目的.视网膜神经纤维层（RNFL）的反射率来自平行于神经节细胞轴突的圆柱形结构的光散射。在两栖动物视网膜中，在440 nm处，微管（MT）贡献了RNFL反射率的约一半。在啮齿类动物视网膜中，MT是导致RNFL双折射的唯一结构。为了增加对临床RNFL测量的解剖学基础的理解，本研究通过使用MT解聚剂秋水仙碱来评估MT对啮齿动物视网膜RNFL反射率的贡献。用多光谱成像反射仪测量了离体大鼠视网膜神经纤维束在460、580和830 nm处的反射率。在很长一段时间内经常拍摄图像。在基线期间，用生理溶液灌注组织。在治疗期间，将溶液转换为对照溶液或含有秋水仙碱的溶液。由于RNFL的高反射率，神经纤维束在较暗的视网膜上表现为明亮的条纹。在对照试验中，束的反射率相对稳定。而秋水仙素处理后，束反射率先迅速下降，然后趋于稳定。秋水仙素处理70分钟后，RNFL反射率在所有波长下均下降至基线以下约50%。MT有助于在所有波长处的RNFL反射率。然而，不像RNFL双折射，这完全消失后，秋水仙素处理，约一半的RNFL反射率后，秋水仙素处理。这一结果表明，除了MT，其他机制可能有助于RNFL反射率。
PURPOSE. The reflectance of the retinal nerve fiber layer (RNFL) arises from light scattering by cylindrical structures oriented parallel to ganglion cell axons. In amphibian retinas, at 440 nm, microtubules (MTs) contribute about one half of RNFL reflectance. In rodent retinas, MTs are the only structure contributing to RNFL birefringence. To increase understanding of the anatomic basis for clinical RNFL measurements, this study was conducted to evaluate the MT contribution to RNFL reflectance in rodent retinas by using the MT depolymerizing agent colchicine.METHODS. Reflectance of nerve fiber bundles in isolated rat retinas was measured at 460, 580, and 830 nm with a multispectral imaging reflectometer. Images were taken frequently over an extended period. During baseline, the tissue was perfused with a physiological solution. During a treatment period, the solution was switched either to a control solution or to a solution containing colchicine.RESULTS. Because of the high reflectance of the RNFL, nerve fiber bundles appeared as bright stripes against a darker retina. The reflectance of bundles was relatively stable in control experiments. With colchicine treatment, however, bundle reflectance at first decreased rapidly and then became stable. After 70 minutes of colchicine treatment, RNFL reflectance had declined to approximately 50% below baseline at all wavelengths.CONCLUSIONS. MTs contribute to RNFL reflectance at all wavelengths. Unlike RNFL birefringence, however, which totally disappears after colchicine treatment, about one half of RNFL reflectance remained after colchicine treatment. This result suggests that, in addition to MTs, other mechanisms may contribute to RNFL reflectance.