ABSTRACT
Background Normal ultrastructure is the anatomical basis of retinal pigment epithelial(RPE) cells to perform normal physiological function.At present the precipitation method is often used to detect the ultrastructure of RPE cells with transmission electron microscopy(TEM).Objective The aim of this study was to explore a simple and feasible approach to examine the ultrastructure of human embryonic stem cell-derived retinal pigment epithelial (hESC-RPE) cells.Methods hESCs were induced and differentiated into RPE cells by the spontaneous differentiation method,and the expressions of microphthalmia associated transcription factor MITF and paired-box gene 6 (PAX6),specific protein of RPE cells,in the cells were detected by immunofluorescence assay.hESC-RPE cells were inoculated into Transwell filter,and the ultrastructure of the cell sheet was examined under the TEM.Then the ultrastructure of the cell sheet specimens was compared with those of hESC-RPE cells from cell precipitation and RPE cell specimens of 90-day-old Long Evans rats.Results MITF and PAX6 were positively expressed in hESC-RPE cells.The normal ultrastructure were visible in the RPE cells of rats under the TEM,including apical microvilli,polarized melanin granules,cellular nucleus,basement membrane and intercellular junctions,and the ultrastructure of hESC-RPE cell sheet on Transwell was similar to the RPE cells in rats.However,only scatter melanin granules,nonpolar nucleus and scanty microvilli were observed under the TEM in the hESC-RPE cells by cell precipitation method.Conclusions Without digestion process,hESC-RPE cell sheet on Transwell can retain the normal ultrastructure of hESC-RPE cells under the TEM,with a more simple and reliable advantage.
ABSTRACT
Objective To evaluate the effect of recombinant human erythropoietin(rhEPO)on pressure induced retinal ischemic injury in rats.Methods The fluorogold(FG)tracing technique was used to observe the survival rate of the retinal ganglion cells(RGCs).Retinal ischemia was induced by increasing the intraocular pressure to 102 mmHg for 60 min in 20 Long Evans rats,then 5 ml rhEPO was injected into the right vitreous chamber immediately and normal saline into the left vitreous chamber as vehicle controls.Another 5 rats without any treatment served as normal controls.All animals were sacrificed at 1,4,7 or 14 d after reperfusion and RGCs were counted to assess the effect of rhEPO.Results The RGCs in eyes treated with intravitreal rhEPO were significantly higher than those in vehicle controls(P
ABSTRACT
Objective To investigate whether endogenous retinal stem cells can be activated in the retina of Royal College of Surgeons (RCS) rats during the onset and development of retinitis pigmentosa. Methods The RCS-p+ rats with inherited retinal dystrophy were divided into 3 groups: the initial stage group (15-day RCS rats), the mid-stage group (30-day RCS rats) and the advanced stage group (90-day RCS rats) according to the severity of degeneration (n=4 in each group). RCS-rdy+p+ rats without retinal degeneration served as controls, and divide into three groups (15-day control, 30-day control, 90-day control) matched with RCS-p+ rats. A transcription factor (Chx10) expressed by embryonic retinal progenitors was detected using immunofluorescence and Western blotting. Results All of the retinal layers in the three control groups and in the 15-day RCS rats did not express Chx10, while the positive expression was observed in the photoreceptor layers of the 30-day and 90-day RCS rats. Chx10 protein could be detected by Western blotting in all RCS groups, but expressed higher in 30-day RCS rats than in 15-day and 90-day RCS rats (P
ABSTRACT
Objective To compare the differences of the electrophysiological and morphological properties of retinal ganglion cells (RGCs) in Long Evans and Wistar rats. Methods Whole cell patch clamp recordings were made from RGCs in the acute retinal slices of Long Evans and Wistar rats aged postnatal 0-31 d. RGCs were stained with Lucifer Yellow diffused into cells during whole-cell recordings for the purpose of morphological study. The sections of rat retinas by HE staining were examined by light microscopy. Results The differences of electrophysiological properties in Long Evans and Wistar rats were not significant. There were pigment granules in retinal pigment epithelial cells of Long Evans but not in those of Wistar rats. Conclusion Long Evans rats can be the good animal model for visual and neural science research in place of Wistar rats.
ABSTRACT
Objective To study the location of embryonic optic cup stem cells during tailbud stage. Methods The embryonic optic cup at embryonic day 11～15 (E11～15) in rats was sectioned horizontally at 15 ?m thick. The distributive characteristics of embryonic optic cup progenitor cells were revealed by immunohistochemistry. Results ①The distribution of optic cup progenitors was mainly aggregated on the optic cup at E12.5. CHX10-positive cells were organized as stratified epithelium arrangement on optic cup inner layer. Clusters of CHX10-positive cells were observed at the edge of optic cup; ② Pigment appeared in the outer layer of optic cup at E13.5, and differentiation into ganglion cells was initiated. Conclusion The distribution of optic cup stem cells is mainly aggregated on the optic cup at E12.5 in which the differentiation into ganglion cells is not initiated.
ABSTRACT
Objective To compare the locations and levels of collagen type Ⅲ, laminin, and fibronectin in Mooren's ulcer and normal human corneas. Methods An indirect immunofluorescent technique and immunohistochemical staining were used to determine the distribution of collagen type Ⅲ, laminin, and fibronectin. The positive results were quantitatively analyzed with an image-processing system. Results Collagen type Ⅲ was not detected in the normal cornea. However, the staining could be seen in the corneal stroma close to Mooren's ulcer focus. Laminin was expressed faintly in the basement membrane of the normal cornea and the positive expression increased in the basement membrane and Bowman's membrane of Mooren's ulcer. In the normal cornea basement membrane, fibronectin was located continuously. In Mooren's ulcer basement membrane, however, fibronectin could not be found in all sections in which one expressed in epithelium and the others in stoma close to the ulcer focus. Conclusion Epithelial basement membrane may play a potential role in the pathogenesis of Mooren's ulcer.