Objective To explore the effect of ischemia-reperfusion injury on the retinal functions of rats. Methods Seventy Wistar rats were selected, 20 of which were selected randomly and divided into two groups (control group and single-irrigated group). The rats were anesthetized and their anterior chambers of the right eyes were cannulated with a 7-gauge needle connected to a reservoir containing ringers balanced salt solution, which was maintained at the same level o f the eye for 1 hour. After that, ERG was recorded in both eyes of all rats. All the left rats were divided randomly into 10 groups and they were treated as the single-irrigated group. Retinal ischemia was induced by raising the reservoir to a height of 150 mm Hg. One hour later except the single ischemia group, all o f t he groups resumed perfusion after 3,6,12,and 24 hours and 3,5,7,14,and 21 days s eparately. ERG was recorded in both eyes of all rats.Results There was no difference in the results of ERG between left and right eyes in either the control group or the single-irrigated group. All the waves of ERG vanished in the single-ischemia group after 1 hour. In the ischemia-reperfusion groups, the waves of ERG partly recovered and the amplitude reduced persistently and progressively.Conclusion Ischemia-reperfusion injury may affect the function of the retina persistently and progressively. (Chin J Ocul Fundus Dis，2003，19：201-268)
Purpose To determine the effect of exogenous interleukin-1alpha; (IL-1alpha;) on the retina and its vasculature and VEGF expression in SD rats． Methods IL-1alpha;2．0 ng (20 mu;l) were injected into the vitreous of 8 left eyes of 8 SD rats while steriled PBS were injected into 8 right contralateral eyes of the same rats as control． All eyes were assessed by direct ophthalmoscopy every day and enucleated on the 7 thpostoperative day． Histological examination (hemato xylineosin staining) and immunohistochemical staining with antibody against VEGF antigen were performed， and sections were observed and photographed under light microscopy． Results ①All 8 IL-1alpha; inject ed eyes developed epiretinal membranes and extraretinal neovascularization on the 3 rd postoperative days while none of the 8 control eyes exhibited any a bnormal retinal vascular changes and they were confirmed by HE staining;②Immuno staining identified VEGF express mainly in the inner layer of vessel walls， the epiretinal membranes， the neuroganglional layer and the photoreceptor layer of retina， while the control eyes showed only weak positive staining in the photo receptor layer． Conclusions IL-1alpha; is capable of inducing vitreo retinal neovascularization，and increasing the expression of VEGF in the retina and epiretinal membranes． (Chin J Ocul Fundus Dis, 2001,17:135-137)
ObjectiveTo investigate the neuroprotective effect of Benztropine on retinal ganglion cells (RGCs) death and optic nerve injury in rats model of non-arteritis anterior ischemic optic neuropathy (rNAION).MethodsA total of 25 Sprague-Dawley rats were randomly divided into Benztropine treatment group (n=13) and PBS control group (n=12). The right eye was set as the experimental eye. rNAION model was established by using rose Bengal combined with laser photodynamic method. The rats in the Benztropine treatment group were received intraperitoneal injection with Benztropine 10 mg/kg (0.2 ml) daily for 3 weeks, while the rats in the PBS control group were received intraperitoneal injection with an equal volume of PBS. At 1, 3 and 7 days after modeling, the retinal and optic disc conditions of the rats were observed by direct ophthalmoscopy. Retrograde labeling, fluorescence microscopy and transmission electron microscopy were used to observe the survival of RGCs and the damage of the optic nerve myelin and axon at 4 weeks after modeling. The RGCs density and survival rate of the two groups were compared by One-Way Anova.ResultsAt 1 and 3 days after modeling, the optic disc edema was observed in the rats of rNAION model group. At 7 days after modeling, the optic disc edema decreased and the boundary was blurred compared with 3 days after modeling.After 4 weeks, the RGCs density in the PBS group was 308±194/mm2 and the survival rate was 13.7%. The density of RGCs in the Benztropine group was 1173+868/mm2 and the survival rate was 47.6%. The differences of RGCs density and survival rate were significant between the two groups (F=7.552, 8.184; P=0.015, 0.012). Myelin disintegration, axon degeneration, onion-like body and gliosis were observed in the optic nerve sections of rNIAON in the PBS group, while the damage of axon and myelin structure in the Benztropine group was significantly less than that in the PBS group.ConclusionsBenztropine group showed higher RGC survival rate, less damage of axon and myelin structure on rNAION model. This study explored the potential neuroprotective effect of Benztropine.
ObjectiveTo investigate the expression of interleukin-18（IL-18）and signal transducers and activators of transcription 5（STAT5）in retina of 4-24-week-old diabetic rats, and explore the potential molecular mechanisms involved in diabetic retinopathy (DR).MethodsRetinal gene expression profile of healthy and 8-week-old diabetic rats was established with restriction fragment differential displaypolymerase chained reaction (RFDD-PCR), and the differences was analyzed by bioinformatics. IL-18 and STAT5 were filtrated as the candidate genes of DR. The expression of IL-18 and STAT5 in retina of diabetic rats with the age of 4, 8, and 24 weeks was observed by semi-quantitative reverse transcriptase-polymerase chain reaction（RT-PCR）.ResultsThe result of RFDD-PCR showed:expression of IL-18 was higher in healthy retina than that in diabetic one; expression of STAT5 was not found in healthy rats but in diabetic ones. The result of RT-PCR showed：compared with the normal, high expression of IL-18 was found in 4-week diabetic retina, reduced in 8-week one, and decreased to the lowest in 24-week one. The expression of STAT5 was not observed in healthy or 4week diabetic retina, but occurred in 8-week one, and increased in 24-week one. ConclusionThe expression of IL-18 and the activation of STAT5 may relate to the occurrance of DR. The expression of IL-18 doesn′t depend on the activation of STAT5. (Chin J Ocul Fundus Dis, 2005,21:258-260)
Objective To observe the inhibition effect of selective cyclooxygenase2 inhibitor（celecoxib）on the experimental choroidal neovascularization（CNV）. Methods Thirty 8-10 weeks old healthy male Brown-Norway（BN）rats were randomly divided into the control, laser and celecoxib group,with 10 rats in each group. At the dosage of 50 mg/kg, celecoxib was gavaged twice per day. After 7 days, experimental CNV was induced by Krypon laser on laser group and celecoxib group. Fundus fluorescein angiography (FFA) was performed on days 3, 7,14,21,30 after laser photocoagulation.On days 21 after photocoagulation, 5 rats in each group were sacrificed and the relative thickness of CNV membranes, the expression of COX-2, vascular endothelial growth factor(VEGF) and matrix metalloproteinase-2(MMP-2) were studied by histopathologic or immunohistochemistry examination.Results On days 21 after photocoagulation, the incidence of CNV in the celecoxib group is significantly lower than that in the laser group (chi;2=7.1068,P=0.0077); the relative thickness of the CNV membranes in the celecoxib group is reduced 41.38% compared to the laser group, the difference is statistically significant (t=16.760 0，P=0.0000).COX-2,VEGF and MMP-2 expression in the CNV membrane of celecoxib group were significantly lower than in control group (t=5.710 0,5.840 0, 8.020 0; P=0.000 0); the COX-2, VEGF and MMP-2 expressions in choroid and retina of control group were weak. Conclusion Prophylactic celecoxib can reduce the expression of VEGF and MMP-2 by inhibiting COX-2, and prevent the CNV induced by laser photocoagulation.
Objective To study value of severe acute pancreatitis (SAP) rat model induced by retrograde pancreaticobiliary duct infusion of methylene blue in combination with sodium taurocholate. Methods The SPF 90 SD rats, 45 male rats and 45 female rats of them, were randomly divided into control group (C group), sodium taurocholate group (ST group) and methylene blue in combination with sodium taurocholate group (MBST group), which were retrogradely infused with the 0.9% normal saline, sodium taurocholate plus DAPI, and methylene blue plus sodium taurocholate plus DAPI respectively into the pancreaticobiliary duct. The success rate of puncture, degree necrosis of pancreas tissue, range of pancreatic lesions, and the incidence of bile or intestinal leakage were compared among the three groups. Results ① The success rate of puncture in the MBST group was significantly higher than that in the ST group (P=0.003) and the C group (P=0.006), which had no significant difference between the ST group and the C group (P=0.782). ② The necrosis degree of pancreas tissues in the MBST group and ST group became more and more severe with the extension of time (P<0.050), which in the MBST group was more serious than that in the ST group (P<0.050). ③ The point of pancreatic lesions range in the MBST group was significantly higher than that in the ST group (P=0.003). ④ The incidence of bile or intestinal leakage in the MBST group was significantly lower than that in the C group (P=0.008) and the ST group (P=0.004). Conclusions Retrograde pancreaticobiliary duct infusion of methylene blue in combination with sodium taurocholate can improve success rate of puncture, aggravate necrosis degree of pancreatic tissue, increase lesion scope of pancreatic tissue, and reduce rate of bile or intestinal leakage, which can provide a stable animal model for basic research of SAP.
Objective To observe the change of diffusion upper limit of macromol ecules through pathological retina and the difference between the layers of retina. Methods Retinal edema was emulated by establishing branch retinal vein occlusion (RVO) model in miniature pig eyes under photodynamic method. Two days later, the retinas of both eyeballs were peeled off. The diffusion test apparatus was designed by ourselves. FITC-dextrans of various molecular weights (4.4, 9.3, 19.6, 38.9, 71.2 and 150 kDa) and Carboxyfluorescein (376 Da) were dissolved in RPMI1640 solutions and diffused through inner or outer surface of retina. The rate of transretinal diffusion was determined with a spectrophotometer. Theoretical maximum size of molecule (MSM) was calculated by extrapolating the trend-linear relationship with the diffusion rate. In separate experiments to determine the sites of barrier to diffusion, FITC-dextrans were applied to either the inner or outer retinal surface, processed as frozen sections, and viewed with a fluores cence microscope. Results FITC-dextrans applying to inner retinal surface, 4.4 kDa dextrans were largely blocked by inner nuclear layer (INL); 19.6,71.2 kDa dextrans were blocked by the nerve fiber layer (NFL) and inner plexiform layer; 15.0 kDa dextrans were blocked by NFL. FITC-dextrans applying to outer retinal surface, most dextrans with various molecular weights were blocked before outer nuclear layer (ONL). No matter applying to the inner or outer surface, Carboxyfluore scein can diffuse through the whole retina and aggregate at INL and ONL. After RVO, the inner part of retina became edema and cystoid, loosing the barrier function. Compared with the normal retina, the MSM in RVO tissues increased (6.5plusmn;0 39nm Vs 6.18plusmn;0.54nm, t=4.143, P=0.0001). Conclusions A fter RVO, the barrier function of inner part of retinal is destroyed and the upper limit of diffusion macromolecule size increased, which is nevertheless limited. ONL acts as bottle-neck barriers to diffusion, if the outer part of retina is damaged, the change of the diffusion upper limit will be prominent. （Chin J Ocul Fundus Dis，2008，24：197-201）
ObjectiveTo analyze the regulative rule of mRNA of vascular endothelial growth factor (VEGF) in mice with oxygen-induced retinopathy, and to elucidate the possible mechanism of occurrence of neovascularization in retinopathy of prematurity (ROP).MethodsSixty 7-day-old C57BL/6J mice were divided into oxygen-induced retinopathy group and control group. In oxygen-induced retinopathy group, 36 mice were exposed to 75% oxygen for 5 days and then to room air for 5 days; in control group, 24 mice were raised in room air. Vascular perfusion of fluorescein and retinal stretched preparation were used to observe the morphologic changes of retinal vessels. Reversal transcriptionpolymerase chain reaction (RT-PCR) was used to observe changes of VEGF mRNA in each group. ResultsIn oxygen-induced retinopathy group, the morphologic characteristics of retinal vessels were the unperfused area at the center of superficial and deepseated vessels, and the neovascularization appeared at mid-peripheral retina after 2 days in relative hypoxia condition. The results of RT-PCR showed space-time corresponding relation between expression of VEGF and neovascularization, which meant that the transcription of VEGF mRNA decreased in hyperxia conditionand increased in relative hypoxia condition. ConclusionHypoxia is the main reason of occurrence of retinal neovascularization; increased expression of VEGF caused by relative hypoxia after hyperxia might be effective in reducing the occurrence of neovascularization in ROP.(Chin J Ocul Fundus Dis, 2005,21:292-295)
Objective To determine whether kringle 4-5 could inhibit choroidal neovascularization (CNV) in mice induced by argon laser photocoagulat ion. Methods Fundus laser photocoagulation was performed on C57BL/6J mice to induce CNV. In treatment group, 20 μg (low dosage group) and 50 μg (high dosage group) kringle 4-5 were injected retrobulbarly after photocoagulation. In control group, equilibrium liquid was injected retrobulbarly. Choroidal neovascularization was evaluated on the 7th and 14th day after photocoagulation by fundus fluorescein ang iography. The mice were killed on the 14th day after photocoagulation, the lesions were evaluated histologically and immunohistochemically, and the expression of CD105 was detected. The Expression of VEGF and bFGF was detected by immunohist ochemistry on the 4th day after photocoagulation.Results The incidence of CNV was 64.3% in control group, 51.2%（P＜0.05）in low dosage group, and 44. 1% (P＜0.01) in high dosage group. The CNV lesions were smaller in kringle 4-5 injected eyes in a dose-dependent manner and the number of proliferative vascular endothelial cells in the subretinal membrane of the treated eyes was smaller than that of the control eyes. There was no significant difference of the expression of VEGF and bFGF between the mice in control and treatment group.Conclus ions Kringle 4-5 could inhibit the development of choroidal neovascularization in the experimental mice model.(Chin J Ocul Fundus Dis，2003，19：201-268)
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)