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AIM: To study the role and mechanism of curcumol in neovascularization induced by vascular endothelial growth factor(VEGF).METHODS: Human umbilical vein endothelial cells were cultured in vitro and treated with 50ng/mL VEGF and curcumol at different concentrations. Cell proliferation was detected by CCK-8 and EdU assay, the migration ability of cells was analyzed by Transwell assay, the angiogenesis ability of endothelial cells was analyzed by tube formation assay, and the change of Akt/mTORC1 signal pathway was detected by Western blot.RESULTS: CCK-8 results showed that the OD450 value of cells in 400 and 800 μmol/L curcumol+VEGF group was significantly lower than that in VEGF group(all P<0.01). EdU results showed that the rate of cell proliferation in 400 μmol/L curcumol+VEGF group was significantly lower than that in VEGF group(P<0.001). Transwell assay and the formation assay results showed that the number of migratory cells in 400 μmol/L curcumol+VEGF group was decreased, and the number and length of tube branches were also reduced compared with VEGF group(all P<0.001). Western blot results showed that curcumol significantly inhibited the expression of p-Akt and p-S6, which were downstream targets of Akt/mTORC1 pathway in cells.CONCLUSION: Curcumol can inhibit VEGF-induced cell proliferation, migration and tube formation of vein endothelial cells, and has a strong inhibitory effect on angiogenesis, which can be further studied in the treatment of ocular fundus neovascularization.
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BackgroundChoriodal neovascularization is an important ocular manifestation of angiogenesis in eyes,which derives from the choroid capillaries.Recent studies have found that complement activation is playing a key role in the laser-induced CNV.Because of the key position of CFB in the alternative pathway,bytargeting CFB and blocking the alternative pathway may provide an approach to observe the role of this alternative pathway in the generation of CNV.Objective This study was to investigate the inhibitory effect of reconstructed complement factor B (CFB)-small interfering ribonucleicacid(siRNA)on choroidal neovascularization (CNV)and its mechanism. Methods Experimental CNV was induced by laser photocoagulation in 96 eyes of 48 clean Brown Norway rats.The rats were randomly divided into 4 groups.25,50 and 75 μg B factor siRNA were injected via caudal vein on 1 day,3,5 days after photocoagulation in different dose groups,and normal saline solution was injected at the same way in experimental control group.Other 12 normal rats were used as blank control group.Fundus fluorescein angiography(FFA) was performed on 3,7,14,21,28 days after injection of CFB-siRNA and CNV was scored.The expressions of vascular endothelial growth factor(VEGF) and factor Ⅷ in choroid were detected by immunochemistry.The expressions of CFB-siRNA,VEGF,transforming growth factor β2( TGF-β2 )proteins in choroid were determined using immunochemistry in 7,14,21,28 days,and the expressions of mRNA of CFB-siRNA,VEGF,TGF-β2 were examined by reverse transcription polymerase chain reaction(RT-PCR). ResultsFFA revealed that the CNV rates in various doses of CFB-siRNA groups were significant lower than those of experimental control group in various time points(P＜0.05),and those in 75 μg B factor siRNA were decreased in comparison with 25 μg B factor siRNA (P＜0.05).Immunochemistry showed that the intensities of the VEGF and factor Ⅶ expression in various doses of CFB-siRNA groups were weaker than the blank control group ( P ＜ 0.05 ).Compared with the control group,the expression of CFB reduced in 7 days,and then approached to the level near the control group.Fourteen to twenty-one days after injection of CFB-siRNA,VEGF and TGF-β2 depressions in different doses of CFB-siRNA groups were lower than blank control group( P＜0.05 ).CFB expression in choroid showed the lower levels in CFB-siRNA injection group compared with blank control group in from 7 through 21 days (P＜0.05).RT-PCR displayed the gradual increase of CFB mRNA and curve-like changes of VEGF and TGF-β2 with time prolong. Conclusions Recombinated CFB-siRNA can effectively inhibit laser-induced CNV by down-regulating the expression of VEGF and factor Ⅷ.Alternative pathway of complement plays an important role in the production of CNV.
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Background Corneal neovascularization (CNV) is an important cause of visual impairment and graft rejection after allograft corneal transplantation in inflammatory corneal diseases. The mechanisms and therapy relating to CNV are intensely investigated at all times. Objective This study was to evaluate the effect of eicosapentaenoic acid (EPA) on CNV induced by alkali cauterization and its mechanism. Methods The animal models of corneal neovasculation were induced in the right eyes in 72 Sprayue-Dawley rats by putting a piece of 3 mmfilter paper with 1 mol/L NaOH at the center of the cornea for 30 seconds. The rats were then divided randomly into the 0.02 mg EPA treatment group (24 rats) ,0.03 mg EPA treatment group (24 rats) ,model group (24 rats) and normal group (6 rats). EPA of 0.04 ml with doses of 0.02 mg or 0. 03 mg or saline solution of 0. 04 ml was injected subconjunctivally in model rats and immediately after cauterization. The presence of CNV and corneal edema were observed daily by slit lamp biomicroscope. 1,4,7 and 14 days after operation, corneal histopathological examination was performed by hematoxylin and eosin staining. The vascular endothelial cells were stained with CD34 by immunohistochemistry,and the expression of IL-1α,IL-6 mRNA and the nuclear factor-κBp65 ( NF-κBp65 ) proteins was measured by reverse transcription polymerase chain reaction (RT-PCR) and Western blot analysis. The use of animals complied with the Regulations for the Administration of Affair Concerning Experimental Animals by Hebei Province( version 1998 ). Results Under the slit lamp, CNV grew slowly from days 2-4 with obvious corneal edema and defect of epithelium. Larger CNV area and less edema were seen from days 7-10. Maximal vessel growth was observed 14 days after injury with thinner vessels in the model group. Histological examination showed that part of the corneal epithelium was damaged;serious corneal edema, more inflammatory cells and a lot of CNV in the stroma were presented in the model group. However, repairing of the corneal epithelium without CNV ,light corneal edema and less inflammatory cells were found in both the 0. 02 mg EPA and 0. 03 mg EPA treatment groups 7 days after alkali cauterization. The relative area of CNV in the 0. 02 mg EPA treatment group was ( 15.80±6.43 )% and ( 11.06±2. 14)% ,and that in the 0. 03 mg EPA treatment group was (16. 10±7.41 )% and (11.06±2. 51 )%, showing significant reduction in comparison with the model group [ (84. 74±7.77)% and (89.63±7.50) % ] 7 days and 14 days after operation ( P＜0. 05 ). Stronger expression of CD34 in the vascular endothelial cells of the cornea stroma was observed in the model group and an absence of CD34 was observed in the EPA-treated groups on the 7th day. RT-PCR revealed that the expression of IL-1α mRNA and IL-6 mRNA was lower in the EPA treatment groups than the model group ( P＜0. 05 ), and Western blot analysis showed that the expression of NF-κB/p65 in the corneas in the EPA treatment groups was significantly lower than that in the model group on the 4th day after operation (P＜0.05).Conclusion Topical application of EPA suppresses CNV induced by alkali burn possibly by inhibiting the expression of NF-κB,IL-1α and IL-6.
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Background There have been an abundance of literature on the analysis of the mechanical characteristic of the sclera at the entire seleral level in high myopia.However,some recent studies on high myopia are focused on the mechanical changes of the sclera on a cellular level. Objective This experiment was purposed to study how transforming growth factor-β2(TGF-β2)affected sclerotic desmocytes and the mechanical behaviors of scleral fibroblasts in the posterior part of the eyes in guinea pigs with experimental myopia. Methods Induced myopic animal models were established by wearing-10.00 D concave lens for 30 days in lateral eyes of 2-week-old guinea pigs.The fellow eyes were used as control group.Another 5 matched animals served as normal controls.The scleral fibroblasts of each group were purified with the tissue explant method and passaged for 2 generations in vitro.Cultured cells were identified by immunochemistry with vimentin,desmin,keratin and S-100 antibodies.Different concentrations of TGF-β2(0,1,10,100mg/L)were added into serum-free DMEM for 24 hours,and the viscoelastic properties of scleral fibroblasts were measured by micropipette aspiration technique. Results Compared with the fellow,eyes and normal control eyes,the equilibrium modulus and apparent viscosity in model eyes were significantly higher(P＜0.05).After treatment of TGF-β2,the equilibrium modulus and apparent viscosity in the model group and fellow eyes were positively correlated with the concentrations of TGF-β2(r=0.743,r=0.533,r=0.654,r=0.576,P＜0.05).Following the addition of 1 mg/L TGF-β2 and 10 mg/L TGF-β2,the equilibrium modulus and apparent viscosity of scleral fibroblasts were significantly reduced in model eyes compared with fellow eyes(P＜0.05).No significant difference was found in the equilibrium modulus and apparent viscosity of scleral fibroblasts between model eyes and fellow eyes after treatment with 100 mg/L TGF-β2(P＞0.05). Conclusion TGF-β2 car increase the mechanic indexes in a concentration.dependent manner.1 mg/L,10 mg/L TGF-β2 can lower the equilibrium modulus and apparent viscosity of scleral fibroblasts of normal eye and thus cause more changes in the mechanical behavior of scleral fibroblasts.
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Background Our previous study demonstrated that curcumin can induce the apoptosis of retinal pigment epithelial (RPE) cells and herein inhibit the proliferation of RPE cells,and it is proved that the intravitreous injection of 0.1mg curcumin has less adverse effect to ocular tissue, inferring a good applicative prospect in clinic. Objective The goal of this experiment was to evaluate the effectiveness of curcumin on the prevention and treatment of experimental proliferative vitreoretinopathy (PVR). Methods PVR models were induced by injection of 0.1ml RPE cells (containing 2×106 cells) into vitreous cavity in 40 eyes of 20 healthy and mature New Zealand albino rabbits.0. 1ml curcumin(0. 1 mg) was then injected into lateral eye of each model rabbit immediately following the injection of RPE cells,and the equal volume of normal saline solution containing 0. 5‰ DMSO was injected into the fellow eye of each model rabbit as controls. On 1,3,7,14,21 and 28 days after injection, the changes of cornea, aqueous humor, lens, vitreous and fundus were examined and recorded by slit lamp biomicroscope, indirect ophthalmoscope,fundus color camera and B-type ultrasonograph to evaluate the inflammatory response. The incidence rate of retinal detachment was calculated and compared between curcumin group and control group. Results The inflammatory reaction in anterior chamber and misty opacity in vitreous were found from 1 day through 3 days after injection, but no obvious proliferative strap and retinal detachment in all of the experimental eyes. On the 7th day after injection, inflammatory reaction was extinct in the anterior chamber of rabbit eyes, and proliferative strap occurred in 14 eyes(75% ) in the control group but only 2 eyes (10% ) in curcumin group,showing significant difference between these two groups (P<0. 01). No retinal detachment was seen in both the two groups. On 14,21 and 28 days after injection, the incidence rate of retinal detachment was 55% ,80% ,95% respectively in control group and that of curcumin group was 10% ,15% ,15% respectively,presenting considerably differences between two groups (P<0. 01, P<0. 01 ,P<0. 01 ). Conclusion Injection of curcumin into vitreous cavity can effectively inhibit the occurrence and development of PVR in rabbit.
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Background Eicosapentaenoic acid(EPA)function as the critical lipid mediators involved in several biological events in human body and play important role in suppressing the genesis of vascular endothelial growth factor (VEGF),migration and proliferation of vascular endothelial cells.Many ocular diseases were proved to be associated with neovascularization.Objecfive The purpose of this study was to investigate the inhibitory effect of EPA on the proliferation of human umbilical vein endothelial cells (HUVEC) indueed by VEGF. Methods HUVEC strain was cultured and passaged,and difierent concentrations of EPA were added to the medium with and without VEGF.The cultured cells were identified by antiofactor Ⅷ polyclonal antibody.The suppressing role of different concentrations of EPA on the proliferation of VEGF-induced or-uninduced HUVEC was assessed by MTT method.The influence of difierent concentrations of EPA on the cellular cycle of VEGF-induced HUVEC was assayed using flow eytometry.The expression of Flk-1,a receptor of VEGF,in the HUVEC Was detected by immunohistochemistry. Results Cultured HUVEC showed the ftlsiform in shape and presented with the cobblestone-like arrangement with the positive response for Ⅷ factor-related antigen.Various concentrations of EPA showed obviously inhibitory effect on VEGF-induced or-unindueed HUVEC at a dose-dependent manner (F=23.072.P=0.000).The inhibitory ability of EPA on VEGF-induced HUVEC was stronger than VEGF-uninduced HUVEC(F=41.417,P=0.000).In 24,48 and 72 hours,the action of EPA on the proliferation of HUVEC was gradually enhanced with the prolong of time(F=1.495,P=0.236).Cell cycle analysis indicated that EPA arrested VEGF-induced HUVEC in G0/G1 phase.The ratio of HUVEC in G0/G1 phase in EPA group was(75.83±1.56)%,and that in control groups was(68.62±1.44)%,showing a significant difference between them(t=-5.88,P=0.00),and no apoptosis of HUVEC was found in both groups.Flk-1 was strongly expressed in the cellular nucleus and cytoplasm in control group.However,the positive expressing intensity of Flk-1 in the HUVEC weakened,and the positive cell number was evidently less in EPA group. Conclusion EPA can inhibit the proliferation of VEGF induced HUVEC through arresting the synthesis of DNA of HUVEC and downregulate the expression of Flk-1 in HUVEC.These results suggest that EPA might exert an antiangiogenic effect.