Objective To explore the correlation between retinal extracellular edema and vitreous contraction in rabbits. Methods Seventeen pigmented rabbit models with retinal vein occlusion (RVO)was set up by laser photocoagulation. Retinal vascularity area was pathologically examined 1 month later.The vitreous gellength under the gravity condition and the percentage of its weight in the rabbits with extraeellular edema was observed. The mechanisms were investigated by Western immunoblotting of type II collagen.Results Extracellular edema was found in 13 experimental eyes 1 month after the formation of RVO (76.5~) with contracted vitreous gel and released watery liquid, and the a component of type II collagen was cross-linked together to form high-molecular-weight components of 1] and 7, which weakened the stability of collagen net structure.Conclusions Vitreous contraction and retinal extracellular edemawere correlated. The main reason may be the cross-links of vitreous collagen that damages the stability of collagen structure. (Chin J Ocul Fundus Dis，2004，20：2-32)
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 2nd, 5th, 8th passage of RPE cells in normal culture, which included cytokeratin 18 (CK18) and α-smooth muscle actin (α-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 5th passage, and it decreased in the following passage, but α-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＜0.05), and α-SMA increased (P＜0.01).
Conclusion
Morphologic changes in epithelialmesenchymal transdifferenetiation of RPE cells are stimulated by VCM and accomplied by the shift of cytoskeleton proteins, The results imply that cells migration may be decreased and contraction may be enhanced in VCM. It may suggest that vitreous accelerates the pathogenesis of PVR and RPE cells play an important role.
(Chin J Ocul Fundus Dis, 2002, 18: 289-292)
Objective To reveal the fibrillar network in vitreous and the effect of plasmin on this network.Methods 20 vitreous gels of freshly slaughtered pigs were divided into 2 groups, the gels in first group were digested by 3 Uplasmin (3 U/ml) at 37c for 24 hours respectively, the second group received the same PBS as control. After digestion, gels were fixed in neutral buffered formalin solution. Samples from vitreous base, cortex and the central region were observed by the technique of freeze etching electron microscopy.Results In vitreous collagen fibril network was in a three-dimensional array, collagen fibril density showed marked differences, central vitreous had the sparse fibril density, the cortex denser and the basal vitreous densest. After digestion by plasmin, the collagen fibrillar network was destructed.Conclusion Collagen fibrils in vitreous present spatial arrangement regularly, plasmin can lead to destruction of the fibrillar network.(Chin J Ocul Fundus Dis，2003，19：179-181)
Objective To observe the effect of the treatment of neodymium-yttrium aluminum garne (Nd:YAG) vitreolysis for the anterior vitreous opacity after implantation of intraocular lens.Methods Forty-nine eyes of 47 patients with the anterior vitreous opacity after implantation of intraocular lens received the slitlamp examination, optical coherence tomography (OCT), and B-scan. The anterior vitreolysis and posterior capsulotomy were performed simultaneously with Nd :YAG laser. The outcomes of visual acuitiy changes and complications were studied.Results In 49 eyes, 46 had anterior vitreous opacity associated with posterior capsule opacification, and the other 3 without obvious posterior capsule opacification. In all patients, the visual acuity improved significantly without any complications after the laser procedure (t=32.50, P=0.007). After Nd:YAG laser treatmen, transparent area was found in anterior opaque vitreous in 21 eyes (42.86%) within 15 minutes, and in 47 eyes (95.92%) within 24 hours. No complication occured in or after the operation.Conclusions In the patients with visual deterioration after implantation of intraocular lens, the prescence of anterior vitreous opacity should be concerned. Opening the opaque anterior vitreous with Nd:YAG vitreolysis is effective for the patients with the anterior vitreous opacity after implantation of intraocular lens.(Chin J Ocul Fundus Dis，2003，19：106-108)
Purpose
To evaluate the surgical effect of idiopathic macular hole (IMH)，with optical coherence tomography (OCT)．
Methods
To measure the diameter of holes and hole halos，the thickness of hole in edge，the changes of hole pattern in 19 cases (19 eyes) with IMH using OCT．
Results
By quantitatively measuring，OCT showed that after surgery the mean hole diameter lessened from （570．95plusmn;264．59 ）mu;m to （337．05plusmn;335．95）mu;m．The mean diameter of hole halo lessened from （1043．53plusmn;278．80）mu;m to （695．00plusmn;483．00）mu;m and the mean thickness of the hole edge thinned from （389．78plusmn;60．58）mu;m to （298．78plusmn;109．80）mu;m．In 17 eyes the holes become closed or reduced in size or the hole halo，and thinned in hole edge．The anatomic successful rate of the surgery is 89%．
Conclusion
OCT can objectively，accurately and effectively judge the anatomic effect of IMH surgery．
(Chin J Ocul Fundus Dis，2000，16：71-138)
Objective
To observe the efficacy of vitreoretinal surgery in the treatment of early traumatized eyes with no light perception.
Methods
We performed vitreoretinal surgery on 17 eyes of early traumatized eyes with no light perception.The patients were followed up for 2～14 months.
Results
Retinal reattachment was achieved in 11 eyes after srugery.8 eyes got visual acuity better than light perception postoperatively.Visual acuities of 5 eyes were better than 0.05 and the best one reached to 0.2.
Conclusion
Timely vitreoretinal surgery is valuable to the early traumatized eyes with no light perception.Retinal reattachment is the most important thing for the treatment of this kind of cases.
(Chin J Ocul Fundus Dis，2000，16：213-284)
Objective To evaluate the indications, effectiveness and complications of vitreoretinal surgery using the 25G transconjunctival sutureless vitrectomy system (TSV25G) under the topical anesthesia. Methods The clinical and follow-up data of 22 eyes of 22 patients undergone vitreo-retinal surgery using TSV25G under the topical anesthesia were retrospectively analyzed. All of the patients were monocular sickened, including idiopathic macular hole in 10 eyes, idiopathic macular pucker in 6, vitreoretinal traction syndrome in 4, and vitreous hemorrhage associated with branch retinal vein occlusion in 2. Peeling of epiretinal membrane and/or internal limiting membrane, intra ocular laser coagulation, air-fluid exchange and tamponiding of C3F8 were performed according to the condition of diseases. The postoperative follow-up was 1-11 months, with the mean duration of 6.4 months. The effect of analgesia, cooperation with the patients, operative effect and complications in and after the surgery were observed. Results The operations finished successfully in all of the eyes under the topical anesthesia. The operation duration ranged from 20 to 25 minutes with average of 22 minutes. The patients cooperated with the doctor well without any discomfort. Two days after the surgery, edema of the wounded conjunctiva was found, and recovered 7 days later. A light pigment dot on the surface of the sclera could be seen at the first month. The complic ations included transient increasing of intraocular pressure in 2 eyes, feather-like opacity of lens in 5 eyes, vitreous hemorrhage in 1 eye, and air-bleb under conjunctiva in 2 eyes. No other complications related with the cut were fo und. The macular hole closed in 9 eyes with idiopathic macular hole, and the other 1 had the smaller but not closed hole. Idiopathic macular pucker, vitreoretinal traction syndrome, and vitreous hemorrhage associated with branch retinal vein occlusion were cured successfully. Conclusions Vitreoretinal surgery using the TSV25G under the topical anesthesia has many advantages such as simple procedure, short operation time, micro-invasion, less complications and rapid revovery, and mainly serves simple manipulation in some simple diseases such as idiopathic macular hole, vitreo-retinal traction syndrome, and simple hemorrhage. (Chin J Ocul Fundus Dis，2004，20：133-136)
Objective
To investigate the effect of tetrandrine (Tet) on experimental choroidal neovascularization and the effect of Tet on retinal structure and function.
Methods
Choroidal neovascularization was induced in 20 Brown Norway (BN) rats (40 eyes) by diode laser (wavelength: 810 nm; exposal time: 0.1 second; facular diameter:100 mu;m; energy: 120 mW), and the rats were divided randomly into experimental and control group with 10 rats (20 eyes) in each group. In experimental group, 0.05 ml Tet with the concentration of 3.21 mu;mol/L was injected intravitreously 0 and 3 days after laser photocoagulation; in the control group, the rats underwent an intravitreous injection with the same volume of sodium chloride solution. The incidence of CNV was evaluated by fundus fluorescein angiography (FFA) 14 days after laser photocoagulation. Five right eyes of another Five healthy BN rats underwent intravitreous injection with 0.05 ml Tet with the concentration of 3.21 mu;mol/L, and an intravitreous injection with the same volume of sodium chloride solution was performed on the left eyes. Before injection, 1 hour, and 1 day after the first injection, and 1 hour, 1 day, 7 days, 14 days after e second injection the electroretinography (ERG) was performed on these 5 rats; 14 days after the second injection, the retinae were examined by light microscopy and transmission electron microscopy.
Results
The incidence of CNV was 23.26% in experimental group，which was obviously lower than that in the control group (63.33%) (Plt;0.01). The ratio of amplitude of b wave of ERG in the rats undergone intravitreous injection with 3.21 mg/ml Tet didnprime;t differ much from which before the injection (Pgt;0.05). There were no structural changes of retinal tissues examined by light and electron microscopy.
Conclusion
Tet may inhibit choroidal neovascularization in rats; there isnprime;t any significant toxic effect of intravitreous injection with Tet on retina at the dosage of 3.21 mu;mol/L.
(Chin J Ocul Fundus Dis, 2006, 22: 242-244)
