ObjectiveTo observe the adhension and stracking of leukocyte in the capillary vessels, and investigate the relationship between leukocyte and microvascular morphologic changes in retinal microvesselsof rats with early diabetes.MethodsA total of 90 healthy adult male Wistar rats were randomly divided into control and diabetes (induced by Streptozotocin, STZ) groups with 45 rats in each group. The rats in the diabetic group were further divided into 3, 7, and 14 days groups with 5 rats in each group, and 30, 90, and 180 days groups with 10 rats in each group. The right eyes of rats in each group were prepared for retinal digest preparations. The expression of leukocyte common antigen (CD45) was detected by immunohistochemical staining.ResultsFew CD45 positive cells in the retinal capillaries were seen in the control group. The expression of CD45 was significantly increased in the retinal capillaries 3 days after diabetes induction, and reached a peak at the 14th day. Morphological changes including capillary telangiectasia, atresia, and irregularity of capillary caliber were found in the retinal capillaries of rats 90 days after diabetes induction. The changes were aggravated 180 days after diabetes induction.ConclusionLeukocyte adhesion occurs in the early stage of diabetic retinopathy (DR), and is the beginning of the microvascular pathological changes. Leukocyte adhesion may play an important role in the occurrence and development of DR as the foundation of microvascular morphological changes.(Chin J Ocul Fundus Dis, 2003,19:344-347)
ObjectiveTo investigate the expression and relation of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in rats with diabetic retinopathy.MethodFifty-five Wistar rats were randomly divided into the control group (10 rats), and 1, 3, and 5-month-diabetes group (15 rats in each diabetes group), and the diabetic models were set up. The expressions of VEGF and bFGF were detected by situ hybridation and immunohistochemistry on retinal paraffin sections.ResultsThe results of situ hybridation showed that expression of bFGF was found in 3-month-deatbtes group with the percentage of 77.8%, and 88.9% in 5-month-deatbtes group; the positive expression of VEGF was not found in 3-month-deatbtes group but in 5-month-deatbtes group with the percentage of 66.7%. Immunohistochemistry indicated that the positive expression of bFGF started in 3-month-deatbtes group with the percentage of 55.6%, and 88.9% in 5-month-deatbtes group; the percentage of the expression of VEGF was 33.3% in 3-month-deatbtes group and 88.9% in 5-month-deatbtes group.ConclusionThe expression of VEGF occurs after the expression of bFGF in rats with DR.(Chin J Ocul Fundus Dis, 2005,21:37-40)
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）
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.
Purpose To evaluate the prostag landins(PG) levels and to identify the effect of dexamethasone(DXM) on PG in response to photochemical insult in rat retina. Methods The experiments were performed on 36 SD rats which were separated into two groups,control and treated groups,and the latter received daily intraperitoneal injections of DXM (1 mg/kg) for 5 consecutive days,starting 3 days before light exposure.The animals were continually exposed to green fluorescent light(510-560 nm)with an illuminance level of (1900plusmn;106.9)lx for 24 hrs.The retinal concentration of PGE 2 and 6-keto-PGF1alpha; were tested at 6hrs,1,3,7 and 14 days after light exposure. Results The PGE2 and 6-keto-PGF1alpha; levels of the control groups (37.50plusmn;2.75,48.06plusmn;4.0 4,81.90plusmn;4.89) pg/mg and (4.68plusmn;0.69,7.50plusmn;0.57,10.40plusmn;0.71) pg/mg had significantly higher values than those of the treated rats(20.60plusmn;4.28,37.36plusmn; 3.34,54.85plusmn;4.57) pg/mg and (2.50plusmn;0.59,4．68plusmn;0.81,6.87plusmn;1.10)pg/mg (Plt;0.01) after 6 hrs,1 and 3 days light exposure respectively. Conclusion By inhibition of PG synthesis,the DXM may play an ameliorative effect on retinal photochemical injury of rats. (Chin J Ocul Fundus Dis,1999,15:94-96)
Objective To observe the inhibitory effect of intravitreal injection of triamcinolone acetonide (TA) on oxygen-induced retinal neovascularization, and to investigate its mechanism. Methods A total of 48 C57BL/6 mice at the age of 7 days were divided into normal group (groupA,n=6), highoxygen group (group B, n=6), TA control group (group C,n=18) and TA highoxygen group (group D,n=18). The retinal neovascularization of group B and D were induced by oxygen. One eye of each mouse of group C and D received an intravitreal injection 2 mu;l (20 mu;g /mu;l) of TA, and the same volume of BSS was injected into the other eye of the mice as BSS control group (group E) and BSS highoxygen group (group F). At postnatal day 17, the retinas were collected and the number of the endothelium cell nuclei of new vessels beyond the inner limiting membrane (ILM) was counted on HE-stained paraffin retina sections. The expression level of vascular endothelial growth factor (VEGF), stromal cellderived factor 1 (SDF-1) and CD14 were measured by immunohistochemical staining. The mRNA expression of VEGF and SDF-1 were detected by real-time RT-PCR. Results The numbers of the endothelium cell nuclei of new vessels beyond the ILM in group A - F were 0, 675, 0, 0, 110 and 688 respectively. In group A and D, it decreased than that in group B and F respectively (t=30.62, 19.532; P＜0.05). There was no difference of VEGF, SDF-1 and CD14 expression between group C and E (t=0.161, 0.284, 0.223; P＞0.05), but the differences were statistically significant between group D and F(t=-2.264, -2.358, -4.897;P＜0.05). There was no difference on mRNA level of VEGF and SDF-1 between group C and E(t=-0.497,-0.709;P＜0.05), but the differences were statistically significant between group D and F(z=-5.137,-4.411;P＜0.05). Conclusion Intravitreal injection with TA can inhibit oxygen-induced retinal neovascularization, down-regulated expression of VEGF and SDF-1 may be the mechanism.
ObjectiveTo investigate the gene expression spectrum of retina and optic nerve after partial injury of optic nerve.MethodsSixty SD rats were randomly divided into 4 groups. The optic nerves of the right eyes were clipped for 6 seconds with a pair of crossaction forceps. The retinae and optic nerves in the operation eye and contralateral sham operation eye were removed 3, 7, 14, and 21 days after the injury to detect gene expression patterns with high-density DNA microarrays.ResultsChanges of a mass of gene expressions were found after the optic nerve injury, and the positive rate of gene expression was 2.35%, 6.48%, 3.82% and 4.09% after 3, 7, 14, 21 days, respectively, and the total positive rate was 11.77%. The functions of positive expression of the gene involved cell survival, cytoskeleton, extracellular matrix and cell adhesion, free radicals and oxidative damage, energy and metabolism, inflammation, neurotransmission and ion transport, signal transduction, structural protein, transcription and translation. Up-or down-regulation of repaired genes was the main part of the changes of gene expression, while the alteredexpression destroy genes was the minor part in the whole gene expression spectrum, in which the up- and down-regulation of expression of repaired genes accounted for 13.98% and 24.73% respectively 7 days after the injury, and the downregulation of expression of repaired genes accounted for 17.20% 14 days after the injury.ConclusionsA mass of gene expression changes occurs after the optic nerve injury, and the comprehensive view on the gene expression pattern following the optic nerve injury is crucial to discover the mechanism of post-injury reaction and regeneration.(Chin J Ocul Fundus Dis, 2005,21:163-166)
Objective To observe the effects of CXCR4 inhibitor (AMD3100) combined with anti-vascular endothelial growth factor (VEGF) antibody on experimental choroidal neovascularization. Methods Choroidal neovascularization (CNV) was induced in 48 BrownNorway (BN) rats by Krypton red laser photocoagulation, and those rats were randomly divided into AF564 group (group A), AMD3100 group (group B), combined treatment group (group C) and PBS group (group D), 12 rats in each group. Left eyes were the experimental eyes. The rats of group A-D received intravitreal injection of 5mu;l of AF564, AMD3100, AF564/AMD3100 and PBS after laser photocoagulation respectively. Fourteen days after photocoagulation, fundus fluorescein angiography (FFA), pathological section analysis and choroidal vascular wholemount were used to observe the degree of fluorescein leakage, the relative thickness and areas of CNV. Results Fourteen days after photocoagulation, the scores of fluorescein leakage in group A - D were 2.16plusmn;0.91, 2.16plusmn;0.91, 1.92plusmn;1.03, 1.39plusmn;0.93 respectively. Fluorescein leakage in group A - C was obviously reduced compared to group D (F=12.91,P＜0.001), while fluorescein leakage in group C was reduced compared to group A and B (F=9.21,P＜0.05). The CNV relative thicknesses in group A-D were 1.82plusmn;0.11, 1.90plusmn;0.22, 1.12plusmn;0.12, 2.82plusmn;0.29 respectively. Group A -C had thinner CNV compared to group D (F=5.92，P＜0.001), while group C had thinner CNV compared to group A and B (F=5.16, P＜0.05). The CNV areas in group A -D were (8204plusmn;122), (9332plusmn;211), (6533plusmn;101), and (13644plusmn;255) mu;m2 respectively. Group A -C had smaller CNV area compared to group D (F=147.50，P＜0.001), while group C had smaller CNV area compared to group A and B (F=112.60, P＜0.05). Conclusion Combined treatment with CXCR4 inhibitor and anti-VEGF antibody can inhibit laser-induced CNV significantly.