ObjectiveTo observe the effect of complement receptor 1 (CR1) on barrier of cultured human retinal epithelial cells (hRPE) under complement-activated oxidative stress. MethodsThe third to fifth passage of hRPE cultured on Transwell insert were used to establish a stable hRPE monolayer barrier. The hRPE monolayer barrier was exposed to 500 μmol/L ten-butyl hydroperoxide and 10% normal human serum to establish the hRPE monolayer barrier model of complement-activated oxidative stress in vitro. hRPE monolayer barriers under complement-activated oxidative stress were divided into two groups including model group and CR1 treatment (1 μg/ml) group. Model group and CR1 treatment group were treated with 1 μl phosphate buffer solution (PBS) or CR1 for 4 hours. Normal hRPE monolayer barrier were used as control in transepithelial resistance (TER) measurement experiment. TER was measured to evaluate the barrier function of hRPE. The hRPE-secreted vascular endothelial growth factor (VEGF) and chemokine (C-C Motif) Ligand 2 (CCL2), together with complement bioactive fragments (C3a, C5a) and membrane-attack complex (MAC) in the supernatant were detected by enzyme-linked immune sorbent assay. ResultsStable hRPE monolayer barrier was established 3 weeks after hRPE seeded on Transwell insert. Complement-activated oxidative stress resulted in a sharp decrease of TER to 54.51% compared with normal hRPE barrier. CR1 treatment could significantly improve TER of barrier under complement-activated oxidative stress to 63.48% compared with normal hRPE barrier(t=21.60, P < 0.05). Compared with model group, CR1 treatment could significantly decrease the concentration of VEGF and CCL2 by 11.48% and 23.47% secreted by hRPE under complement-activated oxidative stress (t=3.26, 2.43; P < 0.05). Compared with model group, CR1 treatment could also decreased the concentration of C3a, C5a and MAC by 24.00%, 27.87%, 22.44%.The difference were statistically significant (t=9.86, 2.63, 6.94; P < 0.05). ConclusionsCR1 could protect the barrier function of hRPE cells against complement-activated oxidative stress. The underlying mechanism may involve inhibiting complement activation and down-regulating the expression of VEGF and CCL2.
Objective To investigate the effects of transformin growth factor-beta (TGF-beta;) and interferon-gamma(IFN-gamma;)on collagen synthesis in human retinal pigment epithelial cells(RPE)． Methods TGF-beta;(0.01～10 ng/ml),recombinant IFN-gamma;(100～10000 Ｕ/ml)or a combination of two were added to cultures of RPE and collagen synthesis of the cells were measured by3 H-proline incorporation assay,indirect immunofluorescence staining and dot-blot hybridization. Results TGF-beta; at 10 ng/ml increased cell uptake of 3 H-proline to 130．87% of controls．It intensified Type IV,I and Ⅲ collagen fluorescent staining as well as mRNA expression．IFN-gamma; at 10000 Ｕ/ml caused 54．72% inhibition of 3 H-proline uptake by RPE,and decreased TypeⅣ collagen fluorescent staining as well as mRNA expression of Type Ⅳ,I and Ⅲ collagens. Conclusion TGF-beta; and IFN-gamma; stimulated and inhibited collagen synthesis of human RPE,respectively．The combination of two had antagonistic effects．IFN-gamma; can be used for inhibition of collagen synthesis of RPE. (Chin J Ocul Fundus Dis, 1999, 15: 245-248)
ObjectiveTo observe the expression of connective tissue growth factor (CTGF) in injured model of retinal pigment epithelial (RPE) cells and the promoting effect of CTGF on migration of RPE cells.MethodsCultured monolayer-confluent human RPE cells were scraped with a trephine and a cotton stick, and set up the injured model of RPE cells with round scraped area. Immunohistochemistry and in situ hybridization(ISH) were used to detect the expression of CTGF protein and mRNA in injured RPE cells at distinct time points after injury. The number of RPE cells migrated to injured area was measured and the effect of CTGF on migration of RPE cells and the effect of dexamethasone (DEX) on the promoting process of CTGF were observed.ResultsThe results of immunohstochemistry and ISH indicated the weak positive expression of CTGF in RPE cells at the edge of scrape 6 hours after injury, and the positive expression increased gradually as time goes by after the injury. Strong positive expression of CTGF in RPE cells at the edge of scrape was found 24 and 48 hours after injury. Rebuilt human CTGF stimulated migration of RPE cells in a dose-depended manner, and DEX significantly inhabited the migration.ConclusionCTGF involves in the procedure of repair of injury of RPE cells, which may play an important role in the pathogenesis of intraocular proliferative diseases such as proliferative vitreoretinaopathy.(Chin J Ocul Fundus Dis, 2005,21:306-309)
Objective To examine the expression of proliferating cell nuclear antigen (PCNA) of retinal pigment epithelial (RPE) cells, thus assessing the role of mechanism of contact inhibition playing in the process of experimental retinal detachment and reattachemnt.Methods Retinal detachment was produced in 72 cats by subretinal injection of 0.25% solution of healon through a micropipette three weeks after extracapsular lens extraction and vitrectomy. Some of the detached retinae were reattached 24 hours later. At different time, the cats were killed and eye globes were fixed and embeded in paraffin. Histologic sections were processed for immunohistochemistry examination using an antibody to detect PCNA protein. Labeled RPE cells were identified, and the proliferation was quantified in detached and un-detached retinae of detachment group, and also in reattached retinae of reattachment group. The comparsion of PCNA-labeled RPE cells in different groups were analyzed by ANOVA. Results In detached regions of detachment group, PCNA-expression of RPE cells occured within 24 hours, and reached a maximum after 5-6 days, then gradually declined to barely detectable levels after 20 days. Similar tendency was found in reattached retinae, but the number of PCNA-labeled RPE cells was obviously small. Fewer PCNA-labeled RPE cells were found in regions of un-detached retinae in detachment group. The difference of these three groups was significant.Conclusion Proliferation of RPE cells is induced when they lose contact with neural retina, but inhibited after neural retina reattached to RPE cells. It suggests that the mechanism of contact inhibition plays a role in the proliferative process after retinal detachment and reattachment. (Chin J Ocul Fundus Dis，2003，19：20-23)
The ultra.structural changes of photic injury to the retina of two patients caused by indirect ophthalmoscope were studied.The duration of exposure was 20 minutes. Under transmission electron microscope, dilation of the choroidal vessels,swelling and vacule formation at all retinal layers, disparsed pyknotic nuclei among the outer nuclear layer and swelling of the nerve fibers were found,The retina of the pregnant woman was injured more severely than that of the male patient. （Chin J Ocul Fundus Dis,1994,10:77-79）