Nash M S, Osborne N N
The Nuffield Laboratory of Ophthalmology, University of Oxford, United Kingdom.
Invest Ophthalmol Vis Sci. 1999 May;40(6):1293-8.
Thy-1 is primarily, if not entirely, expressed by the ganglion cells within the retina. This knowledge was used to index ganglion cell death after ischemia and excitotoxicity by studying changes in Thy-1 mRNA levels.
Insults to the rat retina were delivered either by elevation of intraocular pressure for 60 minutes or by intravitreal injection of N-methyl-D-aspartate (NMDA). After a defined period, changes in Thy-1 immunoreactivity and mRNA levels of Thy-1 and NR1 (NMDA receptor subunit) were used to index ganglion cell sensitivity to damage. Opsin mRNA levels were used as an internal control because photoreceptors lack NMDA receptors.
Retinal Thy-1 immunoreactivity, associated with the ganglion cell and inner plexiform layers, is reduced by ischemia or intravitreal injections of NMDA in a dose-dependent manner. Using a semi-quantitative polymerase chain reaction (reverse transcription-polymerase chain reaction) methodology, the levels of total retinal Thy-1 and NR1 mRNAs were shown to be dramatically reduced after both transient ischemia and intravitreal injection of NMDA. The effect of NMDA was found to be both time- and dose-dependent. In contrast, no change occurred in the levels of opsin mRNA unless high levels of NMDA (200 nmoles) were administered.
Ischemia and NMDA-induced excitotoxicity caused retinal ganglion cell destruction, but the photoreceptors were unaffected. Measurement of total retinal Thy-1 mRNA levels provides a useful way of following ganglion cell death especially when combined with immunohistochemical localization of Thy-1. Additionally, the effect on other retinal cell types such as the photoreceptors can be followed in concert using this technique.
Thy-1主要（即便不是全部）由视网膜内的神经节细胞表达。通过研究Thy-1 mRNA水平的变化，这一知识被用于对缺血和兴奋性毒性后的神经节细胞死亡进行指标化。
通过将眼压升高60分钟或玻璃体内注射N-甲基-D-天冬氨酸（NMDA）对大鼠视网膜造成损伤。在规定时间后，利用Thy-1免疫反应性以及Thy-1和NR1（NMDA受体亚基）的mRNA水平变化来指标化神经节细胞对损伤的敏感性。视蛋白mRNA水平用作内部对照，因为光感受器缺乏NMDA受体。
与神经节细胞层和内网状层相关的视网膜Thy-1免疫反应性，因缺血或玻璃体内注射NMDA而以剂量依赖方式降低。使用半定量聚合酶链反应（逆转录-聚合酶链反应）方法，结果显示短暂缺血和玻璃体内注射NMDA后，视网膜总Thy-1和NR1 mRNA水平均显著降低。发现NMDA的作用具有时间和剂量依赖性。相比之下，除非给予高剂量的NMDA（200纳摩尔）视蛋白mRNA水平才会发生变化。
缺血和NMDA诱导的兴奋性毒性导致视网膜神经节细胞破坏，但光感受器未受影响。测量视网膜总Thy-1 mRNA水平为追踪神经节细胞死亡提供了一种有用的方法，尤其是与Thy-1的免疫组织化学定位相结合时。此外，使用该技术可以同时追踪对其他视网膜细胞类型（如光感受器）的影响。
