Objective To observe the effect of epithelial-mesenchymal transdifferentiation (EMT) of human retinal pigment epithelial (RPE) cells induced by vitreous humor in vitro. Methods The third to fifth passage cultured RPE cells were divided into two groups of treatment by 10% serum containing Dulbecco minimum essential medium (DMEM)/F12 medium (group A), or the same medium supplemented with 25% human vitreous (group B). The morphological changes were observed with a phase contrast microscrope. Cell migration, invasion and contractility were tested using a scratch wound assay, Transwell invasion assay and collagen gel contraction analysis. The expression levels of alpha;-smooth muscle actin (SMA) and Snail1 were detected by reverse transcriptase polymerase chain reaction (RT-PCR). Results The RPE cells in group A were flat and gathered together. The RPE cells in group B grew as a fan-shaped projection at one edge and cone-shaped tail at the opposite edge, or spindle-shaped, and appeared to separate. In group A, filamentous actin distributed mainly at the margin of the cells with the distribution an oval shape. In group B, filamentous actin reorganized and formed fan-like flat pseudopodia at one edge of the cells. Compared to group A, the migration and invasion of the cells increased significantly (t=14.190, 22.630; P＜0.05), but contractility decreased remarkably (t=6.221, P＜0.05) in group B. Compared to group A, the expression level of Snail1 mRNA increased significantly (t=3.218, P=0.032), but the expression level of alpha;-SMA mRNA decreased (t=3.990, P=0.016). Conclusions Vitreous humor can induce the EMT of RPE cells. Increasing cell migration, cell invasion, and expression of Snail1 mRNA as well as up-regulated cellsprime; contractility and expression of alpha;-SMA mRNA may be the mechanism.
Objective To observe the effect of tetramethypyrazine (TMP) on the expression of hypoxia-related factors in human umbilical vein endothelial cells (HUVECs). Methods The second to fifth passage cultured HUVECs were divided into five groups: control group, CoCl2induced hypoxic group and 50, 100, 200 mu;mol/L TMP treatment groups. HUVECs in control group were not treated. HUVECs inCoCl2induced hypoxic group were treated with 150 mu;mol/LCoCl2for four hours. HUVECs in 50, 100, 200 mu;mol/L TMP treated groups were pretreated with 150 mu;mol/LCoCl2 for four hours, followed by treatment with 50, 100, 200 mu;mol/L TMP for eight hours. Real-time reverse transcription-polymerase chain reaction (RT-PCR) was used to detect the mRNA levels of prolyl hydroxylase 2 (PHD2), hypoxia-induced factor-1alpha;(HIF-1alpha;) and vascular endothelial growth factor (VEGF). Protein levels of PHD2, HIF-1alpha;, and VEGF were detected using Western blot. Results Compared with the control group, theCoCl2 induced hypoxic group showed decreased mRNA and protein levels of PHD2 (t=3.734, 3.122;P＜0.05), while those of HIF-1alpha; and VEGF increased (HIF-1alpha; mRNA:t=4.589,P＜0.05; HIF-1alpha; protein:t=3.778,P＜0.05. VEGF mRNA:t=3.926,P＜0.05; VEGF protein:t=3.257,P＜0.05). Compared with theCoCl2 induced hypoxic group, 50, 100, 200 mu;mol/L TMP treated groups showed increased mRNA and protein levels of PHD2 (PHD2 mRNA: t=3.286, 3.617, 3.886;P＜0.05. PHD2 protein: t=2.813, 3.026, 3.078; P＜0.05); while those of VEGF decreased (VEGF mRNA: 50 mu;mol/L TMP: t=1.696,P＞0.05; 100 mu;mol/L TMP:t=2.974,P＜0.05; 200 mu;mol/L TMP: t=3.492,P＜0.05; VEGF protein: 50 mu;mol/L TMP: t=1.986,P＞0.05; 100 mu;mol/L TMP: t=2.976,P＜0.05; 200 mu;mol/L TMP:t=3.136,P＜0.05); although changes in HIF-1alpha;mRNA levels were not statistically significant (t=1.025, 0.726, -1.386;P＞0.05), showed a decrease in HIF-1alpha;protein levels (50 mu;mol/L TMP: t=2.056,P＞0.05; 100 mu;mol/L TMP:t=3.058,P＜0.05; 200 mu;mol/L TMP:t=3.828,P＜0.05). ConclusionIn HUVECs, TMP can upregulate the mRNA and protein expression of PHD2, while down regulating HIF-1alpha; protein expression and VEGF mRNA and protein expression under acute hypoxic conditions.
Objective To observe the neuroprotective effect of alpha;-lipoic acid (ALA) on cultured retinal ganglion cells (RGC-5) under elevated pressure in vitro. Methods Cultured RGC-5cells were divided randomly into 4 groups, including normal control group (group A), negative control group (group B), elevated pressure group (group C) and elevated pressure + ALA group (group D). The cells of group A and C were not intervened with ALA. The cells of group B were treated with 200 mu;mol/L ALA. The cells of group D were treated with different concentrations of ALA (50, 100, 200 mu;mol/L) for one hour. Then cells of group C and D were exerted to 50 mm Hg (1 mm Hg=0.133 kPa) for 24 hours, while the cells of group A and B were exerted to normal pressures for 24 hours. The cell viability was measured using the methyl thiazolyl tetrazolium (MTT) assay and apoptosis was evaluated using 4prime;,6-diamidino-2-phenylindole (DAPI) staining. Expression of MnSOD was determined by realtime polymerase chain reaction (RT-PCR) and Western blot, respectively. Results The cell viability of group B was (65.6plusmn;3.4)%, which lower than that in group D of three concentrations of ALA［(75.1plusmn;3.3)%, (81.8plusmn;2.9)%,(87.9plusmn;3.1)%］, the differences were significantly (t=5.108, 10.007, 12.513;P＜0.05). DAPI staining revealed that characteristic apoptotic changes, such as chromatin condensation,convoluted nuclei with cavitations, fragmentation of the nucleus, and apoptotic bodies appeared in RGC-5cells after 24 ours pressure. There was almost no evidence of apoptosis in group D. RT-PCR and Western blot analysis revealed that the expression of MnSOD mRNA and protein were weakly expressed in group C compared with control A (t=22.045，26.979;P＜0.01). Compared group C with group D, the level of MnSOD mRNA and protein in group D increased significantly (t=9.171, 12.267, 23.567, 7.723, 12.009, 28.198;P＜0.05).In addition, the presence of ALA was found to inhibit hydrostatic pressure induced damage of RGC-5cells in a dose-dependent manner (F=134.273,194.597;P＜0.01). Conclusion ALA can effectively improve the expression of MnSOD in RGC-5cells under the condition of elevated pressure, enhance the ability of RGC-5cells against oxidative damage.
Objective To observe biological characteristics of microencapsulated human endostatin/293 (hES/293) cells at different density and their inhibitory effects on the proliferation of human umbilical vein endothelial cells (HUVEC). Methods The microencapsulated hES/293 cells at different cellular density of 1×104 (group A), 1×106 (group B) and 1×108 (group C) cells/ml were made by polyelectrolyte complexometry technology. The empty microcapsules were set as control group (group D). Each group has 6 samples. After 1, 3, 7, 14 and 35 days in culture, the number of total cells, viable cells was counted by trypan blue staining, and the survival fraction was measured. The grow status of hES/293 cells was measured by MTT assay, and the concentration of endostatin protein in supernatant was measured by enzyme linked immunosorbent assay (ELISA). HUVECs were cocultured with hES/293 cells of group A, B and C. The proliferation of HUVEC at the 24, 72 and 120 hours after coculture was measured by MTT assay. Results The number of total cells and viable cells were increasing and the survival fraction reached its peak after 3 days in culture in group A, B and C. The growth rate in group A was higher than that in group B and C after 3 days in culture (P＜0.05), but the growth rate in group B was higher than that in group A and C after 7, 14 and 35 days in culture (P＜0.05). The concentration of endostatin protein in the supernatant was the same in group A, B and C after 1 and 14 days in culture (P＞0.05). However, group A had higher endostatin than group B and C after 3 days in culture, group B had higher endostatin higher than group A and C after 7 and 35 days in culture (P＜0.05). The hES/293 cells of group A, B and C had no effects on the proliferation of HUVEC(P＞0.05) after 24 hours coculture, but can inhibit the proliferation of HUVEC after 72 or 120 hours co-culture (P＜0.05). Conclusions The microencapsulated hES/293 cells at a density of 1×106 cells/ml can grow and survive, and release endostatin protein stably. The microencapsulated hES/293 cells at different density all can inhibit the proliferation of HUVEC.
Objective To observe the expression of proteins in light-injured retinal pigment epithelial (RPE) cells. Methods ARPE19 cells were exposed to the cool white light at the intensity of (2200plusmn;300) Lx for 6 hours to set up the light injured model. Cellular soluble proteins was extracted and analyzed by means of twodimensional electrophoresis to find out the changes of protein map of lightinjured RPE cells. Results Cellular soluble proteins had (390plusmn;10) spots on the map, in which 11 spots had obvious difference between the light injured group and the normal control group. In the lightinjured cells, the expressio of 8 proteins increased, 1 decreased, and 2 disappeared. Conclusion Twodimensional electrophoresis can find out the difference of expression of proteins in lightinjured and normal RPE cells.
Objective To detect the apoptosis of vascular endothelial cells and retinal pigment epithelial (RPE) cells in vitro induced by verteporfin-photodynamic therapy. Methods Cultured vascular endothelial cells and human RPE cells were incubated with verteporfin at a concentration of 1.0 mu;g/ml which was equivalent to the initial plasma level of verteporfin in clinical therapy. Each kind of cells were divided into 6 groups according to different time of incubation: 0, 5, 15, 30, 60, and 120 minutes group. After incubated, the cells were illuminated by the laser light with the maximum wavelength of absorption of verteporfin (wavelength: 689 nm, power density: 600 mW/cm2) with the power of 2.4 J/cm 2for 83 seconds. The percentage of cellular apoptosis was measured by flow cytometry 3 hours after PDT, and the measurement was repeated thrice. Results The proportion of cellular apoptosis 3 hours after PDT were 0.01plusmn;0.01, 0.25plusmn;0.02, 0.32plusmn;0.02, 0.41plusmn;0.04, 0.49plusmn;0.03 and 0.61plusmn;0.02, respectively in 0-120 minutes group of vascular endothelial cells; and 0.02plusmn;0.01, 0.22plusmn;0.01, 0.31plusmn;0.02, 0.38plusmn;0.03, 0.47plusmn;0.05 and 0.58plusmn;0.03 respectively in 0-120 minutes group of RPE cells. The proportion of cellular apoptosis of both kinds of the cells increased as the incubation time was prolonged. There was no significant difference of the percentage of cellular apoptosis between the accordant time groups in the two kinds of cells (P＞0.05). Conclusions Cellular apoptosis can be quickly induced by verteporfin-PDT both in human vascular endothelial cells and RPE cells; under the same condition in vitro, PDT has no obvious selection for the apoptosis of the two kinds of cells. (Chin J Ocul Fundus Dis, 2006, 22: 253-255)
Objective To explore the effects of Zhaoke defibrase and anti alpha;vbeta;3mAb (23C6) on the adhesion and immigration of bovine retinal vascular endothelial cells. Methods The culture dishes coated with vitronectin (Vn) and collagen，assays of adhesion and immigration were performed 60 minutes after different concentration of Zhaoke defibrase and anti-alpha;vbeta;3 mAb was added to the bovine retinal vascular endothelial cells. The apoptosis of bovine retinal vascular endothelial cells induced by Zhaoke defibrase and anti-alpha;vbeta;3 mAb was detected by electron microscopy. Results Both Zhaoke defibrase and anti-alpha;vbeta;3 mAb inhibited the adhesion and immigration of bovine retinal vascular endothelial cells in a dose-dependent manner. The inhibited concentration (IC50) of Zhaoke defibrase was less than 0.05 mu;mol/L, while (IC50) of anti-alpha;vbeta;3 mAb was more than 2.5 mu;mol/L. 81.8% endothelial cells adhering to Vn were inhibited by 0.1 mu;mol/L Zhaoke defibrase, while 76.3% by endothelial cells adhering to Vn were inhibited by 10 mu;mol/L anti-alpha;vbeta;3 mAb. Typical apoptosis cells were found in bovine retinal vascular endothelial cells after affected by Zhaoke defibrase and anti-alpha;vbeta;3 mAb. Conclusion Both Zhaoke defibrase and anti- alpha;vbeta;3mAb can significantly inhibit the adhesion and immigration of bovine retinal vascular endothelial cells to extracellular matrix， and the mechanism may lie in inducing the apoptosis of endothelial cells. (Chin J Ocul Fundus Dis, 2005,21:118-121)
Objective To investigate the activation and role of signal transduction pathway of epidermal growth factor (EGF)-epidermal growth factor receptor (EGFR)-mitogen activated protein kinase (MAPK) in proliferation of human retinal pigment epithelial (RPE) cells. Methods Human RPE cells were stimulated with 0.1%，10% foetal calfserum (FCS) and EGF(0.1, 1, 10, 50 and 100 ng/ml)in 0.1% FCS Dulbeco′s modified Eagle′s medium (DMEM) and in 10% FCS DMEM for 3 days, respectively. Immunohistochemical staining and in situ hybridization were used to observe the expressions of EGFR protein and EGFR mRNA，respectively. Activation of MAPK was detected by immunohistochemical method with specific anti-phosphorylated ERK 1/2 antibody. Results The optimal concentrations of EGF were 10 ng/ml in 0.1% FCS DMEM and 1 ng/ml in 10% FCS DMEM. After 3 days of stimulation with EGF, phosphorylated ERK 1/2 staining was detectable in nucleus of RPE cells, whereas cells presented immunostaining for phosphorylated ERK 1/2 in the cytoplasm before stimulation. Conclusions EGF may improve the expression of EGFR protein and EGFR mRNA of RPE cells, and induced MAPK nuclear translocation in a concentration-dependent manner. EGF-EGFR-MAPK signal transduction pathway may play a key role in RPE cells proliferation, and serum exerts an important acceclerating function in the process. (Chin J Ocul Fundus Dis，2004，20：67-132)