ABSTRACT
Chronic hypotony is an importnat cause of functional failure after proliferative vitreoretinopathy(PVR) surgery even if the retina is successfully reattached. The purpose of this study was to create a relevant model of chronic hypotony in the rabbit. Eighteen pigmented rabbits weighing 3~4kg were used in this experiment. Pars plana lensectomy was performed on fourteen eyes of fourteen rabbits with a fragmatome and a vitreous cutter. At the end of surgery, 0.2ml of phosphate-buffered saline(PBS) containing 100,000 cells of cultured rabbit dermal fibroblasts was injected over the epiciliary area. As a control, pars plana lensectomy alone was done on four eyes of four rabbits. The intraocular pressure(IOP) was measured on days 7, 14, 21, 28. All fourteen eyes following lensectomy and fibroblast injection had an IOP less than 5mmHg on each follow-up and a mean of 2.5+/-0.6mmHg (mean+/-S.D.) on day 28. Four control eyes with lensectomy alone had an IOP of 7.5+/-2.1mmHg(mean+/-S.D.) on day 28 (P<0.05). On gross examination, the development of fibrous translucent epiciliary membrane was found on day 28. Microscopic examination of eyes obtained on day 28 showed changes in the ciliary epithelium that included an absence or atrophy of the non-pigmented ciliary epithelium, an atrophy and cystic vacuolization of the pigmented ciliary epitheliu, and the interstitial edema of the ciliary body stroma. In conclusion, a model of chronic hypotony with epiciliary membrane using cultured fibroblasts was created in the rabbit. This model may be useful to help elucidate the pathophysiology of chronic hypotony and to investigate potential treatments.
Subject(s)
Rabbits , Atrophy , Ciliary Body , Edema , Epithelium , Fibroblasts , Follow-Up Studies , Membranes , RetinaABSTRACT
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
ABSTRACT
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
Objective To study the changes in the activity of two important enzymes related to the productivity of aqueous humor, namely Na +-K +ATPase and carbonic anhydrase, and to probe further into the mechanism of induction of chronic ocular hypotony by traumatic anterior proliferative vitreoretinopathy. Methods A rabbit model of chronic hypotony induced by traumatic anterior proliferative vitreoretinopathy was reproduced. At the 2nd , 4th, 8th and 16th week after trauma, IOP was measured. Then eyeballs were removed, and a part of ciliary body was harvested for orthodox pathological section and HE staining, and another part of ciliary body was used for determination of Na +-K +ATPase's activity and histochemical assessment of carbonic anhydrase. Result Activity of Na, K-ATPase decreased gradually in the experimental group, but there is no remarkable change in the control group, and the difference was significant. In the experimental group, the activity of carbonic anhydrase was nearly normal, but the activity of carbonic anhydrase in the area of injured epithelium was low, and it was similar to the control. Conclusion Activity of ciliary Na +-K +-ATPase and carbonic anhydrase decrease in activity after traumatic anterior proliferative vitreoretinopathy, which is an important causative factor of chronic hypotony.