Objective To detect expression of NF-κB in the inner retina and in vestigate the inhibitoryeffect of pyrrolidine dithiocarbamate on retinal neovascularization in rats. Methods The rat models with retinopathy were set up un der the hypoxia condition, and fluorescein fundus angiography (FFA) was used to observe the retinal neovascularization. The expressions of NF-κB in the inner retina in rats with and without neovascularization were detected by immunohisto chemical method. PDTC was intraperitoneally injected in rats with neovascularization to observe the expression of NF-κB in the inner retina and the effect on retinal neovascularization. Results Hypoxia induced NF-κB activation in the retinal glial cells and endothelial cells. But immuno-staining intensity for NF-κB and adhesion molecules were reduced by PDTC intraperitoneal injection. Retin al angiogenesis in rats were suppressed effectively (P＜0.05). Conclusions NF-κB activation correlates with retinal neovascularization closely. PDTC may inhibit the NF-κB activation and prove beneficial in the treatment of ischemic neovascularization. (Chin J Ocul Fundus Dis，2003，19：201-268)
Purpose To study an animal model of retinal sheets transplantation using excimer laser. Methods A layer of pure photoreceptors was got by the use of excimer laser.Then the photoreceptor layer was transplanted to the subretinal space of the adult RCS rats which were an animal model of inherited retinal degeneration.The globes were enucleated one month after transplantation.Sections were made for light microscopic examninations. Results A layer of pure and uniform photoreceptors can be got by the use of excimer laser.The transplanted photoreceptors survived well in the subretinal space. Conclusion Retinal sheets transplantation using excimer laser can provide us with well oriented retinal construction and more photoreceptors after transplantation. (Chin J Ocul Fundus Dis,1998,14:209-211)
Purpose To investigate nucleoside diphosphate kinase (NDPK ) expression of tumor metastasis suppressor gene nm23 in heterotransplanted model of retinoblastoma(RB) in nude mice，and analyse the correlation between the expression of nm23 gene and the formation and progression of heterotran splanted RB． Methods SP immunohistochemical method was used to detect the expression of nm23 gene product NDPK in 20 tumors of heter otransplanted RB model and normal retinal tissue． Results The negative staining of nm23/ NDPK was found in normal retinal tissue , whereas 100% expression rate in RB tumors with positive number of 48.73plusmn;2.37． No statistical significance of the expression of nm23/ NDPK was observed between the intraocular growth phase （I～Ⅲ grade） and invasive phase （ Ⅳ～Ⅴ grade）in heterotransplantedRB tumors． Conclusion The function of nm23 gene as a tumor metastasis suppressor in heterotra nsplanted RB tumors was less prominent ,but it may play a role in carcinogen esis and progrssion of RB and may predict poor prognosis． (Chin J Ocul Fundus Dis, 2001.17:47-49)
Objective To further investigate pathologic mechanism of retinal phototrauma. Methods Twenty Wistar rats were divided into control and experimental groups.Their eyes were extracted in 12，24 and 36 hours after light exposure.HE stained retina samples were examined and TDT-mediated dUTP nick end labelling(TUNEL)method was employed to distinguish apoptotic cells. Results After 12-hour light exposure,slight vesiculation was observed in the rod outer segment of the retinas.After 24-hour light exposure,the outer nuclear layer showed predominant fractured and condensed nuclei and fragmented DNA.After 36-hour light exposure,the rod outer and inner segments were lysed and most of the nuclei in the outer nuclear layer were disappeared. Conclusions Apoptosis of photoreceptor cell is one of the important mechanisms which cause experimental retinal photoinjury of rats. (Chin J Ocul Fundus Dis, 1999, 15: 167-169)
Objective It has been shown that pigment epitheliumderived factor (PEDF) is an effective anti-apoptosis agent on several kinds of cells of the central nervous system.This study aimed to evaluate the effect of PEDF on pressure induced retinal ischemia in a rat model. Methods Retinal ischemia was induced by increasing the intraocular pressure to 110 mm Hg for 45 minutes via an intracameral catheter.Ten microlit ers (0.1 mu;g/mu;l) PEDF was injected into the vitreous of 4 eyes of each group im mediately after reperfusion and 4 additional eyes received only normal saline as vehicle controls.The animals were euthanized at 2 or 7 days after reperfusion.T he effect of PEDF on retinal degeneration was assessed by measuring the thicknes s of the inner retinal layers (MTIRL) and counting the retinal ganglion cells (R GC) on plastic embedded retinal sections. Results The MTIRL and the RGC counting in eyes treated with intravitreal PEDF were significantly higher than those in vehicle controls (118.1plusmn;5.0) mu;m vs(94.9plusmn;3.0) mu;m (Plt;0.05);(6.0plusmn;1.0) cells/100 mu;m vs (4.5 plusmn;0.5) cells/100 mu;m (Plt;0.05) 7 days after reperfusion,respectively． Conclusion Intravitreal administration of PEDF can ameliorate an ischemiareperfusion retinal injury and may be useful to prevent neuronal degeneration in the inner retina. (Chin J Ocul Fundus Dis, 2001,17:138-140)
Objective To analyse the changes of nitric oxide and nitric oxide synthase in rat retina under acute high ocular pressure and study the effect of nitric oxide in rat retinal damage under hypertension. Methods Sixty Wistar rats were divided randomly into five groups:Ocular hypertension 30 min,60 min,90 min and 12 h,24 h after reperfusion．Elevation of the ocular pressure in the anterior chamber of the rat eye ca used retina ischemic damage．The changes of retinal nitric oxide content were ob served indirectly by measuring NO2－/NO3－ content in retina.The distribution and changes of neuronal constitutive nitric oxide synthase (ncNOS)were studied by immunocytochemical localization of ncNOS. Results ncNOS positive neurons were distributed in the inner nuclear layer (INL),ganglion cell layer (GCL) and the inner plexiform layer of the normal and ischemic rat retina.During acute high IOP 30 min,60 min and 90 min,NO content decreased gradually and ncNOS immune activity weakens.During reperfusion,NO content increased remarkably (Plt;0.05) as compared with the groups of hypertension 90 min and decreased remarkably as compared with the normal rat retina.But ncNOS positive neurons continue to decrease compared with the groups of hypertension 90 min. Conclusion NO participates the rat retinal injury by acute elevated intraocular pressure, and nitric oxide synthetized by ncNOS may play an important role in protecting the retina from ischemic and post-ischemic injury.
Objective To monitor the release of amino acids of the whole retina during and after experimental glaucoma by increasing the intraocular pressure （IOP）． Methods Experimental glaucoma was induced in one of the two eyes of rabbits by increasing IOP at 120 mm Hg for 45 min under infusion of saline in anterior chamber；then the pressure was released and the needle inserted into the anterior chamber was removed，this state was maintained for another 45 min．Every 15 min during the experiment 5 rabbits were killed and experimental eyes were enucleated．Aliquots（20 μl）of the retinal extracts（see below）were mixed with ophthaldialdehyde reagent and analysed for amino acid content by the HPLC method of Wangwei，using a 150 mm×4.6 mm,5 μm C18 column． Results A large increase in the release of glutamate，but not of the other three amino acids monitored，occurred during initial experimental ocular hypertension．It reached peak value of（111.73±17.46）10-5 mmol/g at 15 min of hypertension．15 min after release of intraocular pressure，again，immediately large and specific increase in the concentration of glutamate was reached to（102.96±51.91）10-5 mmol/g．In eyes subjected to paracentesis of anterior chamber，no difference was found between experimental eyes and controls. Conclusion These results suggest that glutamate is triggered by increasing the IOP，and it releases not only during the period of experimental ocular hypertension，but also afterwards. (Chin J Ocul Fundus Dis, 2002, 18: 146-148)
Objective To determine the effect of thiazolidinediones (TZDs) on early retinopathy in rats with experimental diabetes. Methods In 40 rats, diabetic models were set up in 36 by one-off intraperitoneal injection with streptozotocin (STZ), and other 4 were in the normal control group. Twenty-four diabetic rats with the disease-duration of more than 6 months underwent intravitreous injection (with rosiglitazone or pioglitazone in 10 rats, respectively), and the rest 4 rats werenprime;t injected with drugs as the diabetic positive control group. Immunohistochemical treptomycin-avidin-biotin-complex (SABC) method, in situ hybridization of retinal vascular endothelial growth factor (VEGF) mRNA, and TdT-dUTP terminal nick-end labelling (TUNEL) were performed on the ocular paraffin section to detect the cellular apoptosis. The difference of VEGF expression and cellular apoptosis between TZDs and control group was observed and analyzed. Results The results of immunohistochemical staining and hybridization in situ were negative in the normal control group. The positive expression rate of VEGF was lower in rosiglitazone and pioglitazone group than which in the diabetic positive control group, and there was no obvious differences of positive expression of VEGF mRNA and cellular apoptosis between the 2 groups. Conclusion TZDs (rosiglitazone and pioglitazone) may inhibit the positive expression of VEGF protein in retina of STZ-induced diabetic rats to some extent, but not affect the growth of VEGF in retina. (Chin J Ocul Fundus Dis, 2006, 22: 7-10)
Objective To observe the inhibitory effects of construction of complement factor (CFB)small interference RNA (siRNA) on choroidal neovascularization（CNV）induced by photocoagulation in rats.Methods We constructed an expression vector of CFBsiRNA by cutting CFBsiRNA and plasmid pRNATU61/Neo. Experimental CNV was induced by photocoagulation in 42 Brown Norway rats. After the model was set up, the rats were randomly divided into tail intravenous injection, vitreous injection, subretinal injection, and control group; each group except the control one had a corresponding blank plasmid control group. CFBsiRNA was injected 1, 3, and 5 days respectively after photocoagulation in the injection groups; the dosage was 50, 20, and 10 mu;g in tail intravenous injection, vitreous injection, and subretinal injection group respectively, while no injection was give to the control group after photocoagulation. Before and 14 days after photocoagulation, fundus fluorescein angiograoph (FFA) was performed and CNV development was judged by the leakage; the expression of vascular endothelial growth factor (VEGF) and factor Ⅷ were detected by immunohistochemistry. Results The leakage of fluorescein was obvious lower in tail intravenous injection group than that in the control group (chi;2=15.1620,Plt;0.05). The expression of VEGF and factor VIII in tail intravenous injection group at different time points after photocoagulation didnprime;tdiffer much (F=20.35,18.33; Pgt;0.05); while was apparently lower than that in the other groups at different time points (F=77.96,55.68; Plt;0.05).All of the groups, except tail intravenous injection group, had higher expression of VEGF and factor VIII 14 days after photocoagulation compared with that 7 days after photocoagulation (F=60.89, 61.12; Plt;0.05).Conclusions Constructed CFBsiRNA can inhibite CNV by downregulating the expression of VEGF and factor Ⅷ.
PURPOSE:To investigate and changes of the retina and the chorid induced by lipopolysaccharide (LPS)in Lewis rats and to compare the results obtained on tissue wholemounts and sections. METHODS:Immunohistochemistry was carried out both on wholemounts of the retina and the chorid-sclera complex and on ocular sections from normal Lewis rats and those after LPS injection. RESULTS:It was shown on the tissue wholemounts that monocytes were attached to retinal blood vessels and emigrated into the choroid as early as 4hrs after LPS injection. Severe involvement of the retina and macrophages into whole area of these tissues.Furthermore increasing number of major histocompatibility complex classⅡ(MHC classⅡ)positive cells was observed in the choroid.The results on tissue sections revealed that the retina and the choroid were both involved as videnced by infiltration of these cells at some time points after LPS injection. CONCLUSION:Wholemount technique provides undoubtful evidences to show that the retina and choroid are primarily and severely involuted after LPS injection.The endotoxin induced uveitis is,for the first time,presumed to be model for human generalized uveitis. （Chin J Ocul Fundus Dis,1996,12:33-36）