ObjectiveTo discuss the role and effect of the triamcinolone acetonide (TA) injection applied in the vitreoretinal surgery for assisting to distinguish and removal residual cortex.MethodsOne thousand and forty-six patients (1 056 eyes) underwent a PPV at West China Eye Center from August 2003 to February 2005. These affected eyes were selected without posterior vitreous detachment pre-and intra-operatively, and underwent intravitreal injection with TA 1-2 mg to label the residual vitreous cortex on the surface of the posterior retina after removal of the majority vitreous.ResultsThe location and coverage of the residual vitreous cortex were clearly be shown by the white appearance of TA labeled residual vitreous, and the residual vitreous cortex was conveniently to be recognized and removed.ConclusionThe application of intravitreal injection with TA is helpful for identification and elimination of the residual vitreous cortex in vitreoretinal surgery.(Chin J Ocul Fundus Dis, 2005,21:226-228)
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.