He Jiucheng, Bazan Haydee E P
Neuroscience Center of Excellence and the Department of Ophthalmology, Louisiana State University Health Sciences Center, School of Medicine, New Orleans, LA, USA.
Exp Eye Res. 2015 Jun;135:182-91. doi: 10.1016/j.exer.2015.03.005. Epub 2015 Mar 7.
The aim of this study was to map the entire nerve architecture and sensory neuropeptide content of the rabbit iris. Irises from New Zealand rabbits were stained with antibodies against neuronal-class βIII-tubulin, calcitonin gene-related peptide (CGRP) and substance P (SP), and whole-mount images were acquired to build a two-dimensional view of the iridal nerve architecture. After taking images in time-lapse mode, we observed thick nerves running in the iris stroma close to the anterior epithelia, forming four to five stromal nerve rings from the iris periphery to the pupillary margin and sub-branches that connected with each other, constituting the stromal nerve plexus. In the anterior side, fine divisions derivated from the stromal nerves, forming a nerve network-like structure to innervate the superficial anterior border layer, with the pupillary margin having the densest innervation. In the posterior side, the nerve bundles ran along with the pupil dilator muscle in a radial pattern. The morphology of the iris nerves on both sides changed with pupil size. To obtain the relative content of the neuropeptides in the iris, the specimens were double stained with βIII-tubulin and CGRP or SP antibodies. Relative nerve fiber densities for each fiber population were assessed quantitatively by computer-assisted analysis. On the anterior side, CGRP-positive nerve fibers constituted about 61%, while SP-positive nerves constitute about 30.5%, of the total nerve content, which was expressed as βIII tubulin-positive fibers. In addition, in the anterior stroma of the collarette region, there were non-neuronal cells that were positive for SP. On the posterior side, CGRP-positive nerve fibers were about 69% of total nerve content, while SP constituted only up to 20%. Similarly, in the trigeminal ganglia (TG), the number of CGRP-positive neurons significantly outnumbered those that were positive for SP. Also, all the SP-positive neurons were labeled with CGRP. This is the first study to provide a two-dimensional whole mount and a cross-sectional view of the entire iris nerve architecture. Considering the anatomical location, the high expression of CGRP and SP suggests that these neuropeptides may play a role in the pathogenesis of anterior uveitis, glaucoma, cataracts and chronic ocular pain.
本研究的目的是绘制兔虹膜的完整神经结构和感觉神经肽含量。用抗神经元类βIII微管蛋白、降钙素基因相关肽（CGRP）和P物质（SP）的抗体对新西兰兔的虹膜进行染色，并采集整装图像以构建虹膜神经结构的二维视图。在延时模式下拍摄图像后，我们观察到粗大的神经在靠近前上皮的虹膜基质中穿行，从虹膜周边到瞳孔边缘形成四到五个基质神经环以及相互连接的分支，构成基质神经丛。在前侧，由基质神经分出的细小分支形成神经网络样结构支配浅表的前边界层，瞳孔边缘的神经支配最为密集。在后侧，神经束呈放射状与瞳孔开大肌一起走行。两侧虹膜神经的形态随瞳孔大小而变化。为了获得虹膜中神经肽的相对含量，标本用βIII微管蛋白和CGRP或SP抗体进行双重染色。通过计算机辅助分析定量评估每个纤维群体的相对神经纤维密度。在前侧，CGRP阳性神经纤维约占总神经含量的61%，而SP阳性神经约占30.5%，总神经含量以βIII微管蛋白阳性纤维表示。此外，在瞳孔领区的前基质中，有SP阳性的非神经元细胞。在后侧，CGRP阳性神经纤维约占总神经含量的69%，而SP仅占20%。同样，在三叉神经节（TG）中，CGRP阳性神经元的数量显著多于SP阳性神经元。而且，所有SP阳性神经元都被CGRP标记。这是第一项提供整个虹膜神经结构的二维整装和横断面视图的研究。考虑到解剖位置，CGRP和SP的高表达表明这些神经肽可能在前葡萄膜炎、青光眼、白内障和慢性眼痛的发病机制中起作用。
