Abstract
Abstract: :
Purpose: In the retina, Thy-1 is expressed predominantly on retinal ganglion cells (RGCs). Numerous studies have been performed on Thy-1 mRNA levels or its immunoreactivity as an index of RGC number. In this study, we established a two-site enzyme immunoassay (EIA) that detects trace amounts of Thy-1 protein and assessed RGC death both in vitro and in vivo using this novel EIA system. Methods: Recombinant rat Thy-1 expressed in E. Coli was purified and used as standard for Thy-1 EIA. To assess the relation between the number of RGCs and Thy-1 protein levels, we performed Thy-1 immunohistochemistry and Thy-1 EIA of primary retinal cell cultures that were maintained in the presence or absence of brain-derived neurotrophic factor. As an in vivo model, intravitreal injections of N-Methyl-D-aspararte (NMDA) were carried out to investigate the neurotoxic effects of NMDA on RGCs by morphological methods and Thy-1 EIA. Results: We have established a novel Thy-1 EIA and succeeded in quantification of retinal Thy-1 protein levels. Thy-1 EIA value of retinal cell cultures were changed in accordance with the number of RGCs determined by Thy-1 immunoreactivity. Retinal Thy-1 immunoreactivity is markedly reduced by intravitreal NMDA injections. Using Thy-1 EIA, the levels of total retinal Thy-1 protein were dramatically reduced after intravitreal injection of NMDA, in parallel with the reduction of RGC number. Conclusion: Quantitative measurement of retinal Thy-1 protein level using Thy-1 EIA provides a useful way of following the number of RGCs after retinal injuries.
Keywords: 415 ganglion cells • 489 neuroprotection