Noninvasive and simultaneous imaging of layer-specific retinal functional adaptation by manganese-enhanced MRI
Noninvasive and simultaneous imaging of layer-specific retinal functional adaptation by manganese-enhanced MRI
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DOI：
10.1167/iovs.05-1588
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发表时间：
2006-06-01
影响因子：
4.4
通讯作者：
Luan, Hongmei
中科院分区：
文献类型：
--
作者：
Berkowitz, Bruce A.;Roberts, Robin;Luan, Hongmei
目的：检验高分辨率（视网膜内分辨率为23.4微米）锰增强磁共振成像（MEMRI）可用于无创且同时记录大鼠视网膜不同层面对与功能适应相关离子的细胞需求这一假设。
方法：在对照大鼠中，在明适应或暗适应期间，在全身注射或不注射氯化锰的情况下收集高分辨率图像；比较视网膜内层和外层的信号强度。在单独的实验中，在清醒的暗适应对照大鼠全身给予氯化锰1个月后，使用以下指标评估锰离子对眼部健康可能产生的毒性作用：视网膜层厚度、眼内压以及血 - 视网膜屏障完整性。
结果：在未注射锰的大鼠中，视网膜内层和外层在明、暗状态下的信号强度差异无显著差异（P>0.05）。相反，在给予锰之后，在明/暗条件下视网膜外层信号强度的变化显著大于视网膜内层。在氯化锰注射1个月后，与对照组相比，通过整体和视网膜内层厚度、眼内压以及血 - 视网膜屏障完整性评估，未发现对眼部健康有有害影响的证据。
结论：目前的MEMRI检查是一种安全（即无毒）且相对简单的操作，似乎能有力地反映与明、暗视觉处理相关的正常视网膜生理反应相关的特定层视网膜离子需求。在一系列用于研究正常发育和衰老的动物模型中，可以设想对视网膜离子需求进行全面的MEMRI测量。
PURPOSE. To test the hypothesis that high-resolution (23.4 mu m intraretinal resolution) manganese-enhanced magnetic resonance imaging (MEMRI) can be used to noninvasively and simultaneously record from distinct layers of the rat retina cellular demand for ions associated with functional adaptation.METHODS. In control rats, high-resolution images were collected with or without systemic injection of MnCl2, during light or dark adaptation; inner and outer retinal signal intensities were compared. In separate experiments, 1 month after systemic administration of MnCl2 to awake dark-adapted control rats, possible toxic effects of Mn2+ on ocular health were assessed with the use of the following metrics: retinal layer thickness, intraocular pressure, and blood retinal barrier integrity.RESULT. In nonmanganese-injected rats, the signal intensity difference between light and dark states for inner and outer retina was not significantly different (P > 0.05). In contrast, after manganese administration, the change in outer retinal signal intensity under light/dark conditions was significantly greater than that of inner retina. At I month after MnCl2 injection, comparisons with controls revealed no evidence for deleterious ocular health effects as assessed by whole and inner retinal thickness, intraocular pressure, and blood retinal barrier integrity.CONCLUSIONS. The present MEMRI examination was a safe (i.e., nontoxic) and relatively straightforward procedure that appeared to robustly reflect layer-specific retinal ion demand that correlates with normal retinal physiology responses associated with light and dark visual processing. Comprehensive MEMRI measures of retinal ion demand may be envisioned in a range of animal models for the study of normal development and aging.