Objective
To quantify the mRNA expression of NMDAR1 gene in the retina of eyes with acute elevation of IOP in rabbit．
Methods
Tweenty-six eyes of 16 rabbits were divided into three groups: Group 1: The IOP of one eye in 10 rabbits was elevated to 60 mm Hg by ante ri or chamber infusion． Group 2: The another eye of the same rabbit in group 1 was maintained the IOP to 20 mm Hg by anterior chamber infusion． Group 3: Unilat eral eyes of six rabbits were enucleated to evaluate the mRNA levels as normal control group． PCR product was identified by Southern blotting and the mRNA expression level was quantified by RT-PCR．
Results
The results revealed no significant difference between group 1 and group 2．
Conclusion
This implies that acute elevated IOP may not affect the mRNA expression level of NMDAR1 gene．
(Chin J Ocul Fundus Dis, 2001,17:50-51)
Objective
To study the effects of neonatol rabbit Schwann cells(SC) on repair of optic contusion in adult rabbits.
Methods
24 h after the adult rabbit optic nerves was contused,0.1 ml of SC suspension (group A) and saline water (group B) were injected into the vitreous of injured eyes respectively.All the animals were studied by retinal ganglion cell (RGC) and axon counting,flash visual evoked potential (FVEP) tests at various intervals after injury.
Results
At the 4th week after injury,the number of RGC was (19.89plusmn;3.79)/mm in group A and (12.67plusmn;4.12)/mm in group B,and the density of axons was (94.569plusmn;793)/mm2 in group A and (36.085plusmn;285)/mm2 in group B.There was dramatical difference between group A and B (Plt;0.01).The amplitude of FVEP wave of group A increased from 48% to 88% on the 3rd day after injury,and still dept 78% at the 8th week and group A was significantly higher than group B at various intervals (Plt;0.01).
Conclusion
SC are effective in promoting the repair of optic nerve contusion by increasing the survival rate of RGC,rescuing axons from degeneration,and dramatically promoting the function of the optic nerve.
(Chin J Ocul Fundus Dis,2000,16:91-93)
Objective
To investigate the effect of suppression of ischemia-induced retinal neovascularization by VEGF antisense oligodeoxyribonucleotides.
Methods
Mouse models of hyperoxia-induced ischemic retinopathy were established. Retrobulbar injections were performed with VEGF antisense oligodeoxyribonucleotides or NS in 4 groups:normal control and various doses respectively. The nuclei of new vessel buds extending from the retina into the vitreous in differ ent groups were counted and compared under the light microscope.
Results
There were plenty of new vessel buds in the eyes of mice in hyperoxic condition., while the number of the nuclei of new vessel buds is less in the murine eyes with retrobulbar injection of VEGF antisense oligodeoxyribonucleotides,especially the nuclei were redused with 59.3% in eyes with large dose.
Conclusion
The proliferation of retinal new vessel may be suppressed by using the retrobulbar injection of VEGF antisense oligodeoxyribonucleotides.
(Chin J Ocul Fundus Dis, 2001,17:141-143)
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)
ObjectiveTo observe the expression of CD147, matrix metalloproteinases-2 (MMP-2) and vascular endothelial growth factor (VEGF) in a rat model of oxygen induced retinopathy (OIR).
MethodsEighty-four neonatal Wistar rats were divided into two groups randomly, the hyperoxia group (n=42) and the control group (n=42). Oxygen induced retinopathy was established in the hyperoxia group, the control group was raised in room air. Wholemonts were prepared from postnatal day (p) 7 and 14 rat retina to observe retinal vascular morphology. The number of endothelial cells to break through the internal limiting membrane was counted from p14 retinal paraffin sections. Expression of CD147, MMP-2 and VEGF protein levels was analyzed by immunohistochemistry on p12, p14, and p16 retinal sections. At the meantime, correlation between CD147 and MMP-2, VEGF was analyzed by two-way analysis of variance (ANOVA) test.
ResultsAt p7, the retinal vasculature of the control group was radial distributed with large caliber. In OIR group, there were vasoconstriction, large area of avascular zone and a few small areas of vascular network. At p14, the normal untreated rat had interwoven retinal vasculature, but in OIR group, the retinal vasculature was expanded and tortuous, and forming lots of neovascular cluster in the boundary of the perfusion and non-perfusion regions resulting exudation and hemorrhage. At p14, the endothelial cell nuclei breakthrough the internal limiting membrane was (1.30±1.26) and (19.70±3.56) respectively in control and OIR group, the difference was statistically significant (t=21.813, P<0.01). Immunohistochemical staining showed that CD147, MMP-2, VEGF expression was low in control group but high in OIR group. From p12 to p16, CD147, MMP-2 and VEGF protein expression increased in OIR retinas compared with control samples(p12:t=5.612, 4.122, 4.955; P<0.01. p14:t=11.390, 8.047, 12.176; P<0.01. p16:t=6.355, 4.422, 5.110; P<0.01).
ConclusionCD147, MMP-2 and VEGF were highly expressed in the rat model of oxygen induced retinopathy.
Objective
To investigate the damage to the retinal cells and apoptosis of retinal cells of rats after ischemia-reperfusion insult.
Methods
The retinal ischemia-reperfusion model was developed by increasing intraocular pressure to 109725 mm Hg in rat eyes. Morphological changes of the rat eyes were observed by means of routine histopathology with HE staining. Apoptosis of the retina was assayed by both DNA fragmentation gel-electrophoresis and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labelling (TUNEL).
Results
Compared with the normal control, no histopathological changes were revealed in the rat retinas 30 min after the ischemia and then reperfued for 24 h or 48 h. Retinal ganglion cell layer (RGL) and inner plaxiform layer (IPL) of the retina were observed, however, to become significantly thinner 60 min after the ischemia and then reperfued for 24 h or 48 h. Together with the pathological changes DNA ladder pattern was detected in the same group of the rats. Further, immunochemical stain of the eye demonstrated that TUNEL positive cells were localized in RGL and IPL of the retina.
Conclusion
Ischemia-reperfusion insult of the eye may remarkably damage the retina of the rat eye. The damage to the retinal cells is mainly localized within RGL and IPL and apoptosis is the important mechanism of the retinal disorder.
(Chin J Ocul Fundus Dis, 2002, 18: 296-298)
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 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)
Purpose
To investigate whether experimental autoimmune uveitis can be induced equally in different rats by urea soluble fraction of bovine melanin-associated antigen(USF-BMAA),and,if so,difference among them.
Methods
Lewis rats,F344 rats,Wistar rats were immunized with USF-BMAA emulsified with complete Freud is adijuvant and Bordelella pertussis to induce experimental autoimmune uveitis.The animal models were investigated clinically and histopathologically and compared with each other.
Rusults
Experimental autoimmune uveitis could be induced in Lewis rats,F344 rats and Wistar rats with US-BMAA.Clinical and histopathalogical examination showed that bilateral ocular inflammation developed after immunization 9-13 days.Although inflammation was mainly located in anterior uvea,a mild focal choroiditis was noted in those with severe anterior inflammation.No inflammation was observed in the retina and pineal gland.Experimental autoimmune uveieis induced with USF-BMAA was similar to experimental autoimmune anterior uveitis incited with BMAA presented by other authors.Inflammation induced with USF-BMAA in F344 rats and in Lewis rats was quite similar in the severity and course of the model.But the inflammation was less in Wistar rats compared with that in Lewis rats and F344 rats.
Conclusion
Experimental autoimmune anterior uveitis was successfully induced with USF-BMAA in Lewis rats,F344 rats and Wistar rats.The difference with regard to the severity among these aminals were propably attributed to their genetic bankground.
(Chin J Ocul Fundus Dis,1998,14:149-152)
Purpose
To observe the pathologic changes of retinal photic injury in mice.
Methods
A light damaged trunk was designed by ourselves.The mice were given an intermitent light exposure for 3 days,12 hours light exposure every day and 12 hours dark adaption before every exposure.Experimental animals were sacrificed on the 1st,6th,12th,18th and 30th day after light injury,and the eyes were enucleated for light and electronic microscopy observation.
Results
The early pathologic changes including disc membrance swelling,disorganization in outer segments,and mitochondrial swelling,spherical change in inner segments．Then the chromatin densification,liquefaction and margination,and the shrinkage of nuclear membrance were found in the nuclear layer.Finally the outer nuclear layer became thin and disappeared.The apical microvill of RPE cell disappeared and basic fold became flat in some samples.
Conclusion
The photoreceptor degeneration was the pathologic characteristic of retinal photic injury in mice.
(Chin J Ocul Fundus Dis,1998,14:215-218)
