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Objectives:To establish animal model of anterior proliferative vitreoretinopathy (aPVR) with cultured homologous dermal fibroblasts of rabbit, and to provide evidence why hypotony was caused by aPVR. Methods:Animal models of aPVR were established with cultured homologous dermal fibroblasts on pigmented rabbits. Rabbits were sacrificed on the 14th, 28th and 56th day after the operation to prepare naked eyes and to receive histological examinations. Results:Naked eye examination showed that the peripheral retina was detached by dragging in the experimental group 28 and 56 days postoperatively. Microscopic examination showed atrophy or absence of the non-pigmented ciliary epithelium on the 28th and 56th postoperative day in the experimental group. Conclusions:The epiciliary membrane in aPVR dragged the ciliary body, made atrophy of non-pigmented epithelium, which perhaps was the main cause of hypotony.
ABSTRACT
Objective To investigate the occurrence, progress and conversion of hypotony in anterior proliferative vitreoretinopathy (aPVR), and to provide knowledge about how to prevent and treat it. Methods Animal models of chronic hypotony by aPVR were made with cultured homologous dermal fibroblasts on pigmented rabbits. The intraocular pressure (IOP) and ultrasound biomicroscopy(UBM) examination were taken preoperatively and on days 7,14, 28 and 56 postoperatively. Rabbits were killed on days 14, 28 or 56 postoperatively, prepared for histology and ultrastructure examination. Results The average IOP of experimental group was lower than that of control group on days 7,14,28 and 56 significantly (P
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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.
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Objective To study the occurrence, development and outcome of hypotony following traumatic anterior proliferative vitreoretinopathy (aPVR), so as to provide a theoretical basis for its prevention and treatment. Methods An animal model of chronic hypotony following traumatic aPVR was reproduced in rabbits. The intraocular pressure (IOP) was measured before the experiment and on days 7, 14, 28 and 56 after the injury. Rabbits were killed on days 14, 28 and 56 after the experiment, prepared for pathological and ultrastructure examination. Results The average IOP of experimental group was significantly lower than that of control group on days 7, 14, 28 and 56 (p
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Objective To study the dynamics of aqueous humor in chronic hypotony induced by traumatic anterior proliferative vitreoretinopathy (aPVR), and to demonstrate physiologic mechanisms of the hypotony. Methods A model of hypotony to simulate traumatic aPVR was reproduced in rabbits. Preoperatively and on day 7, 14, 28 and 56 postoperatively, the aqueous humor flow rate and the uveoscleral outflow of aqueous humor were determined. Results The flow rate of aqueous humor in experimental group was reduced remarkably compared with that of control group on days 14, 28 and 56 (P
ABSTRACT
To establish a model of experimental retinal detachment and reattachment, extracapsular lens extraction and vitrectomy were performed in 78 adult cats. After three weeks, a glass micropipette with a flat tip (diameter 150～200?m) was inserted between the neural retina and retinal pigment epithelium (RPE) monolayer. Retinal detachments were produced by subretinal injection of 0.25% solution of Healon through this micropipette. Twenty～four hours later, detached retinas were reattached by air-fluid exchange and subretinal fluid drainage with a glass micropipette. Then 30% perfluoropropane (C 3F 8) gas temponade was porfomed. Retinal detachment was successfully made in 93.6%(73/78), and 97.1%(33/34)of the detached retinas were successfully reattached. By light microscopy, histologic sections showed that seperated retina located between RPE cells and photoreceptors, and neural retina contacted to RPE cells closely in reattached retinas. In conclusion, by using micropuncture, we have established an animal model of retinal detachment and reattachment with minimum injury to the retina, and a high rate of retinal detachment and reattachment were obtained.