Objective To observe the electrophysiological and morphological features of retinal ganglion cells (RGCs) in rats, and investigate its effect on the visual signal conduction. Methods Whole cell recordings were obtained from 112 RGCs of 30 rats at the age of 7-30 days. Resting membrane potential (RMP) was recorded, and input impedance was noted after given 2 mV hyperpolarizing current by voltage clamp. The action potential (AP) was induced by deplorizing current at different densities. The histological staining was actualized by injecting with biotin into the RGCs, and the diameter of the cells was measured. Results Three different discharge patterns of RGCs in response to maintained depolarizing currents were recorded: single spike (25 RGCs), transient firing (40 RGCs), and sustained firing (47 RGCs). The diameter was 14-16 ?m in 57.14% transient firing RGCs, and 10-12 ?m in 62.50% sustained firing RGCs. The maximum frequency of AP of sustained firing RGCs was significantly higher than that of transient firing RGCs (P

Purpose To investigate the effects of human vitreous fluid on proliferation of cultured human retinal pigment epithelial (RPE) cells and vascular endothelial cell lines(VEC304). Methods Human RPE cells and VEC304 were cultured and treated in different human vitreous conditioned medium (VCM) with or without serum, vitreous volume concentrations of VCM were 1∶8, 1∶4 and 1∶2. Cells proliferation was assayed by tetrazolium (MTT) colorimetry at the 2nd, 4th and 6th day respectively. Results In the presence of serum, 1∶4, 1∶2 VCM had a significantly stimulative effect on RPE cells proliferation compared with control group at the 2nd, 4th, and 6th day retrospectively ( P

Objective To study the transplantation of embryonic full-thickness retina, including neural retina and retinal pigment epithelial (RPE), into the subretinal space of rats and to investigate the development of the grafts. Methods A total of 34 eyes from 3-week-old pigmented rabbit embryos were treated with the dispase to obtain pieces of the full-thickness retina, and then grafts were injected into the subretinal space of the right eyes of 20 Wistar rats and 14 RCS (Royal college of surgeons) rats. Host rats were sacrificed at 3, 7, 14, and 28 d after transplantation. Sections were stained with hematoxylin eosin and immunohistochemistry. Results The rabbit embryonic retina was capable of developing and differentiating in the subretinal space of the host rats. Conclusion The rabbit embryonic retina is capable of developing and differentiating in the subretinal space of host rats. Transplantation of xenografts of embryonic full-thickness retina is practicable, but the methods of transplantation need to be improved.

Objective To describe cultured human retinal pigment epithelial (RPE) cells transdifferentiation and investigate the effects of human vitreous fluid on the morphologic and cytoskeleton changes of RPE cells in vitro. Methods Cytoskeleton characteristics in the 2 nd, 5 th, 8 th passage of RPE cells in normal culture, which included cytokeratin 18 (CK18) and ?-smooth muscle actin (?-SMA) were analyzed by Western blot. RPE cells were cultured in human vitreous-conditioned medium (VCM) at the concentration of 1∶4 for 6 days, morphologic changes were examined by light and electron microscopy, and cytoskeleton characteristics were analyzed by imunocytochemistry and Western blot. Results During culture in vitro, RPE cells lost epithelial characteristics and aquired fibroblast-like phenotype. The expression of CK18 was the highest at the 5 th passage, and it decreased in the following passage, but ?-SMA increased gradually. The morphologic transdifferentiation from epithelial to fibroblast-like cells of RPE was accelerated by VCM. Ultrastructural changes such as decreased microvilli and gradually increased rough endoplasmic reticulum and Golgi complex were found during the cultivation. CK18 produced by RPE cells decreased in VMC (P

Objective To explore the distribution and features of the optic cup stem cells in embryonic rat at tailbud stage. Methods The distribution of optic cup stem cells in optic cup tissue in 12.5-embryonic-day-old rats was observed by immunohistochemistry. The separated cells from optic cup were cultured with serum-free media, and immunofluorescence technique was used to detect the ability of hyperplasia of stem cells and expression of CHX10 antigen and specific antigens of mature retinal cells before and after differentiation. Results The optic cup stem cells in embryonic rat at tailbud stage were mainly located at inner, outer, and marginal layer of optic cup. No expression of specifically marked protein of mature retinal cells was detected. The cells separated from optic cup had the ability of single-cell clone, positive expression of CHX10 and expression of several specific antigens of mature retinal cells after the inducement, including Thy1.1, glial fibrillary acidic protein (GFAP), protein kinase C (PKC) ?, and rhodopsin. Conclusion Optic cup of 12.5-embryonic-day-old rats composes of undifferentiated cells, and the stem cells are mainly located in optic cup inner and marginal. High ability of hyperplasia of the optic cup stem cells cultured in vitro is found. The cells, which are retinal stem cells, can express several specifically marked proteins of mature retinal cells after inducement and differentiation.

Objective To study the membrane properties of rat retinal ganglion cells during postnatal development, including the passive membrane properties and the action potentials evoked by depolarizing current injections and the relationship between the membrane properties and ages. Methods Whole cell patch clamp recordings of the retinal ganglion cells (RGCs) in retinal slices of postnatal rats (age ranging from postnatal days 7 to 30) were performed. Results (1) A total of 112 RGCs were recorded from postnatal rats. (2) The electrophysiological properties of RGCs changed significantly during development. The excitability of RGCs increased in an age-dependent manner. There was significant difference between before-eye-opening group(P7-13d) and after-eye-opening group(P14-30d) . (3) Three different discharge patterns of RGCs in response to sustained depolarizing current pulses were recorded: single-spike firing, transient firing and sustained firing. During development, retinal ganglion cells of rats exhibited pronounced changes in the discharge patterns(P

Objective To investigate the electrophysiological properties of retinal ganglion cells(RGCs) in Long Evans rats during different postnatal developmental stages so as to explore the intracellular mechanism of retinal neuron maturation. Methods Whole cell patch clamp recordings of RGCs in acute retinal slices of Long Evans rats (postnatal days 3 to 31) were performed. Depolarizing current pulses of different densities were inflicted on RGCs to evoke action potentials(AP) . Results A total of 94 RGCs, single spike cells, transient and sustained cells, were acquired in 33 rats. The proportion of the three types of TGCs was different. There was significant difference in electrophysiological properties. Conclusion During the period of postnatal development, gradually matured electrophysiological properties of RGCs and differences in amplitudes and frequencies of AP suggest that different types of RGCs may play different roles in coding and transmitting spatial and temporal information.

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.

Objective To explore the electrophysiological properties and the disparity of visual cortical neurons in developing rats. Methods Whole cell patch clamp recording and intracellular labeling of brain slices were performed on rats at postnatal 14 and 28 days. The electrophysiological data were analyzed according to the cellular input resistance and resting membrane potential. Results When the input impedance of visual cortical neurons(IR) was lower, increased peak value of postsynaptic currents(PSCs), prolonged rise and decay time were found. At postnatal 14th day(before eyes opened), the intermediate cells and mature cells were 59.2% and 14.9% respectively, but at postnatal 28th day(14 days after eyes opened), the mature cells and immature cells were 62.5% and 12.5% respectively. Conclusion During the period of postnatal development, the visual cortical neurons become mature gradually, but maturation is not completely correlated with age.

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.