Honjo M, Tanihara H, Kido N, Inatani M, Okazaki K, Honda Y
Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Japan.
Invest Ophthalmol Vis Sci. 2000 Feb;41(2):552-60.
To elucidate the role of retinal Muller cells in N-methyl-D-aspartate (NMDA)- or kainic acid (KA)induced retinal damage.
In experimental eyes, NMDA or KA was injected into the vitreous of rat eyes. Immunohistochemistry and western blot analysis were conducted to elucidate expression and localization of glial fibrillary acidic protein (GFAP) and ciliary neurotrophic factor (CNTF). In addition, the neuroprotective effects of CNTF were calculated by counting cells in the ganglion cell layer (GCL) and by measuring the thickness of the various retinal layers.
Morphometric analysis of retinal damage in NMDA- and KA-injected eyes showed significant cell loss in the GCL and thinning of the inner plexiform layer (IPL) of the retina, but not of other retinal layers. Immunohistochemistry demonstrated disappearance and/or decrease in immunoreactivities of calbindin- and calretinin- positive cells and their neurites and upregulated expression of both GFAP and CNTF in experimental eyes. Western blot analysis showed an increase in protein expression for CNTF in retinas of experimental eyes. Confocal images and sequential localization demonstrated colocalization of CNTF and GFAP in the inner retinal layer and possibly in Muller cells. In addition, pretreatment with CNTF (1 microg) before the intravitreal injection of NMDA (or KA) demonstrated that CNTF has neuroprotective effects against NMDA- or KA-induced neuronal death in the retina.
These studies revealed the upregulated expression of CNTF and GFAP in Muller cells in response to NMDA- and KA-induced neuronal death, suggesting that production of CNTF in Muller cells may be a part of the endogenous neuroprotective system in the retina.
阐明视网膜穆勒细胞在N-甲基-D-天冬氨酸（NMDA）或 kainic 酸（KA）诱导的视网膜损伤中的作用。
在实验眼中，将NMDA或KA注入大鼠眼玻璃体内。进行免疫组织化学和蛋白质印迹分析以阐明胶质纤维酸性蛋白（GFAP）和睫状神经营养因子（CNTF）的表达和定位。此外，通过对神经节细胞层（GCL）中的细胞进行计数以及测量视网膜各层的厚度来计算CNTF的神经保护作用。
对注射NMDA和KA的眼睛的视网膜损伤进行形态计量分析显示，GCL中细胞明显丢失，视网膜内网状层（IPL）变薄，但其他视网膜层未变薄。免疫组织化学显示，实验眼中钙结合蛋白和钙视网膜蛋白阳性细胞及其神经突的免疫反应性消失和/或降低，GFAP和CNTF的表达上调。蛋白质印迹分析显示，实验眼视网膜中CNTF的蛋白表达增加。共聚焦图像和序列定位显示，CNTF和GFAP在视网膜内层可能在穆勒细胞中共定位。此外，在玻璃体内注射NMDA（或KA）之前用CNTF（1微克）预处理表明，CNTF对NMDA或KA诱导的视网膜神经元死亡具有神经保护作用。
这些研究揭示了在NMDA和KA诱导的神经元死亡后，穆勒细胞中CNTF和GFAP的表达上调，表明穆勒细胞中CNTF的产生可能是视网膜内源性神经保护系统的一部分。
