Objective To evaluate the inhibited effects of small interfering RNA targeting Rac1 (Rac1-siRNA) on rat retinal neovascularization in retinae. Methods Retinal vein occlusion was induced by retinal photodynamic medthod in 25 Sprague-Dawley rats. Rac1-siRNA vector DNA was injected into the vitrous of one eye of those rats (gene intervention group), and empty vector DNA was injected into the fellow eye (blank control group). Rac1-siRNA vector was injected in other 25 SD rats without retinal vein occlusion (blank intervention group). Two weeks after injection, fluorescein isothiocyanate (FITC)-dextran was perfused into the hearts of all the rats, and the retinal wholemount was made to observe the neovascularization. The numbers of endothelial cells which break through the internal limiting membrane were counted after hematoxylin-eosin staining. Results A massive of neovascularization and FITC leakage were found in blank control group. Small part of neovascularization and a little FITC leakage were observed in the gene intervention group. Retinal vessels were normal in blank intervention group. Compared with blank contrast group and blank intervention group, the difference of the mean numbers of endothelial cells which broke through the internal limiting membrane in the gene intervention group was significant（t=? P=0.000??lt;0.05）. Conclusion Rac1-siRNA can inhibit retinal neovascularization induced by retinal vein occlusion in rats.
Interleukin-18 is an inactive precursor which lacks a signal peptide, it has a role in regulating retinal pathological angiogenesis. It also inhibits experimental choroidal neovascularization (CNV) via interferon-γand thrombospondin-1. Currently little is known about its mechanisms of inhibition for CNV, may be speculated to be due to effects of anti-angiogenesis, down-regulates vascular permeability and lower vascular endothelial growth factor (VEGF) levels via directly acting on the vascular endothelial cell and epithelial cells. Exogenous administration of mature recombinant interleukin-18 has no adverse effect on retinal pigment epithelial cell viability. In addition, the anti-VEGF role of interleukin-18 is tested to be safe and effective for humans. Interleukin-18 alone or in combination with anti-VEGF shows to be a good prospect for improving the prognosis of experimental CNV. However, more large clinical studies are required to confirm the exact efficacy of interleukin-18 for CNV.
Myopic macularpathy is the main cause of the decline of visual function in high myopia, which including tigroid fundus, lacquer cracks, diffuse retinal choroid atrophy, plaque retinal choroid atrophy, choroidal neovascularization (CNV), Fuchs spot and posterior staphyloma. The tigroid fundus is the initial myopic retinopathy. The lacquer cracks is a special lesion in the posterior pole of high myopia. When the lacquer cracksen enlarge or lacquer cracks progress to plaque retinal choroid atrophy should be paid to monitoring the occurrence of CNV. Myopic macularpathy progression include two mode. One is from tigroid fundus——lacquer cracks——plaque retinal choroid atrophy——CNV to macular atrophy. And the other is from tigroid fundus——diffuse retinal choroid atrophy——atrophy enlarge to diffuse retinal choroid atrophy with plaque retinal choroid atrophy or plaque retinal choroid atrophy occurence on the border of posterior staphyloma. Understanding the progression patterns and natural course of these lesions will help the clinic to further understand the course of high myoipa.
Objective To investigate the effects of knocking down Rac1 gene (ras-related C3 botulinum toxin substrate 1) by small hairpin RNA (shRNA) on retinal neovascularization in a mouse model of oxygen-induced retinopathy (OIR). Methods One hundred and eight 7-day-old C57BL/6J mice were divided into three groups randomly.The OIR was induced by Smith protocol in 2 groups. OIR mice received an intravitreal injection of Rac1-shRNA plasmid or the nonsense plasmid in the geneintervention group and control group respectively at the age of postnatal day 11 (P11). Non-OIR mice also received an intravitreal injection of Rac1-shRNA plasmid at P11 as the blankintervention group which lived in the normoxic environment.Retinal neovascularization was investigated on flat-mounts after fluorescence angiography at P15 and P17. Endothelial cell nuclei breaking through the internal limiting membrane were counted on pathological section at P17.The expression of Rac1 and NF-kappa;B p65 subunit was measured by immuohistochemistry, Western blot, real-time polymerase chain reaction (RT-PCR) and in situ hybridization. Results Compared with the blank-control group,the level of Rac1 mRNA in the gene-intervention group decreased obviously（t=4.500，P=0.001）;the retinal non-perfusion areas,fluorescence leakage, neovascularization and the number of endothelial cell nuclei breaking through the internal limiting membrane were reduced significantly（t=6.521,P＜0.001）; the level of NF-kappa;B p65 nuclear translocation decreased（t=16.008,P＜0.001）while the expression of NF-kappa;B p65 mRNA was reduced obviously（t=3.354,P=0.006）, which was positively correlated with the expression of Rac1-mRNA (P=0.012).Conclusion Intravitreal injection of Rac1-shRNA with liposome in mice can effectively inhibit the expression of Rac1,and inhibit the retinal neovascularization under relative hypoxia via blocking the ROS-NF-kappa;B pathway.
Objective To investigate the related factors of effects on distant visual acuity after photodynamic therapy (PDT) for choroidal neovascularization (CNV). Methods One hundred and thirty-five cases (135 eyes ) of CNV treated with PDT were observed. The gender, preoperative distant and near visual acuity, disease course, pathogeny, area of CNV, types of CNV ascertained by fundus fluorescein angiography (FFA), and changes of CNV in FFA were recorded. Multi-factor regression analysis of visual acuity within 1 month and 3 months after PDT was performed with SPSS statistics software. Results The distant visual acuity within 1 month postoperatively was related to the preoperative distant visual acuity, the area of CNV and the changes in the FFA（P=0.000,0.030,0.062）, and 3 months after PDT, it was related to the distant and near visual acuity preoperatively and the changes in the FFA（P=0.000,0.054,0.034）. The condition of distant visual acuity within 1 month postoperatively was related to the FFA type of CNV and the disease course（P=0.018,0.08）. Conclusion The smaller the area of CNV is, the better postoperative distant visual acuity would be. The proportion of improvement of visual acuity is relatively higher in patients with classic CNV. Early treatment for the patients with the indicatio may improve the visual acuity effectively. (Chin J Ocul Fundus Dis，2004，20：292-294)
ObjectiveTo evaluate the macular visual function of patients with myopic choroidal neovascularization (MCNV) before and after intravitreal injection of conbercept.MethodsA prospective, uncontrolled and non-randomized study. From April 2017 to April 2018, 21 eyes of 21 patients diagnosed as MCNV in Shanxi Eye Hospital and treated with intravitreal injection of conbercept were included in this study. There were 9 males (9 eyes, 42.86%) and 12 females (12 eyes, 57.14%), with the mean age of 35.1±13.2 years. The mean diopter was ?11.30±2.35 D and the mean axial length was 28.93±5.68 mm. All patients were treated with intravitreal injection of conbercept 0.05 ml (1+PRN). Regular follow-up was performed before and after treatment, and BCVA and MAIA micro-field examination were performed at each follow-up. BCVA, macular integrity index (MI), mean sensitivity (MS) and fixation status changes before and after treatment were comparatively analyzed. The fixation status was divided into three types: stable fixation, relatively unstable fixation, and unstable fixation. The paired-sample t-test was used to compare BCVA, MI and MS before and after treatment. The x2 test was used to compare the fixation status before and after treatment.ResultsDuring the observation period, the average number of injections was 3.5. The logMAR BCVA of the eyes before treatment and at 1, 3, and 6 months after treatment were 0.87±0.32, 0.68±0.23, 0.52±0.17, and 0.61±0.57, respectively; MI were 89.38±21.34, 88.87±17.91, 70.59±30.02, and 86.76±15.09, respectively; MS were 15.32±7.19, 21.35±8.89, 23.98±11.12, 22.32±9.04 dB, respectively. Compared with before treatment, BCVA (t=15.32, 18.65, 17.38; P＜0.01) and MS (t=4.08, 3.50, 4.26; P＜0.01) were significantly increased in the eyes 1, 3, and 6 months after treatment. There was no significant difference in the MI of the eyes before treatment and at 1, 3, and 6 months after treatment (t=0.60, 2.42, 2.58; P＞0.05). Before treatment and at 1, 3, and 6 months after treatment, the proportion of stable fixation were 28.57%, 38.10%, 38.10%, 33.33%;the proportion of relatively unstable fixation were 47.62%, 47.62%, 52.38%, 57.14% and the proportion of unstable fixation were 23.81%, 14.28%, 9.52%, 9.52%, respectively. The proportion of stable fixation and relatively unstable fixation at 1, 3 and 6 months after treatment were higher than that before treatment, but the difference was not statistically significant (x2=1.82, 1.24, 1.69; P＞0.05).ConclusionBCVA and MS are significantly increased in patients with MCNV after intravitreal injection of conbercept.
For choroidal neovascularization (CNV) secondary to pathological myopia, intravitreal injection of anti-VEGF has been widely used in clinic and achieved good outcome. However, due to the differences in the demographic characteristics, stages of disease progression and treatment procedure of CNV, the prognosis of the disease is variable. Complete ellipsoid band, smaller baseline choroidal neovascularization and better baseline vision are important predictors of good outcome of anti-vascular endothelial growth factor treatment. Chorioretinal atrophy or complications related to pathologic myopia indicate a poor prognosis. The influence of age, race, previous photodynamic therapy and early treatment on the prognosis of treatment need to be further studied.
