Objective To investigate the inhibitory effects of fms-like typrosine kinase receptor sFlt-1 on retinal neovascularization (RNV).Methods Recombinant lentivirus sFlt-1（2-3）and sFlt-1（2-4）expressing the sFlt-1 (2-3) and (2-4) immunoglobulinlike regions of sFlt-1 were constructed. 96 seven-day-old C57/6J mice were randomly divided into 4 groups with 24 mice in each group. Group 1: normal control; group 2: experimental control; group 3: sFlt-1（2-3）; group 4: sFlt-1（2-4）.The mice in group 2-4 were exposed to hyperoxia with （75plusmn;2）% O2 for 5 days and then returned to normoxia with 21% O2;the mice received an intravitreal injection with 1 mu;l virus of empty vector, sFlt-1（2-3）,or sFlt-1（2-4）,respectively. Five days later, all mice underwent perfusion fluorecein angiography and retinal wholemont was made to observe the changes of retinal vessels; retinal sections were stained by hematoxylin and eosin and RNV endothelium cell nucleus were counted; vascular endothelial growth factor(VEGF) and VEGF receptor-2 (KDR/Flk-1) protein were measured by Western blot.Results Seventeen days after birth, the retinal area of fluorescein leakage and RNV, RNV nucleus which breaking through inner limiting membrane in group 3 and 4 were smaller or less than that in group 2（P＜0.01）; while VEGF protein didnprime;t changed much （P＞0.05）the expression of KDR/Flk-1 decreased significantly (P＜0.01). Conclusion sFlt-1（2-3）and sFlt-1（2-4）can inhibit the formation of oxygen-induced RNV,the former virus has a better effect.
【Abstract】Objective To understand the features of lymphatic vessel, and to summarize the foundation and mechanism of the promotion and inhibition of tumor lymphangiogenesis recorded on the current studies of animal experiments and clinical researches. Methods The related literatures of the structural features of lymphatic vessel, lymphatic endothelial molecular markers, the origin of lymphatic tumors, the molecular mechanisms and regulatory factors were reviewed, and the relationship between tumor lymphangiogenesis and lymphatic metastasis, the treatment targeting at the formation of the anti-tumor lymphatic vessel and its existing problems were also analyzed. Results Hyperplasia of lymphatic vessels occurred during the process of tumor formation and progression. The structural features of the lymphatic vessels in the tumor were conducive to tumor lymphatic metastasis. In recent years, methods of anti-lymphangiogenesis and inhibition of tumor lymphatic metastasis had achieved considerable success in animal experiments. However, there were still a lot of problems need to be solved. Conclusion Tumor lymphangiogenesis has a significantly positive correlation between tumor lymphatic metastasis and patients’ prognosis, which may indicate that treatment against the formation of tumor lymphatic vessel maybe effective.
Objective To observe the expression of vascular endothelial growth factor receptor-1 (VEGFR-1) and VEGFR-2 in hypoxic chorioretinal endothelial cells of monkeys (RF/6A), and to evaluate the effect of minocycline. Methods RF/6A was cultured and divided into four groups: control group, hypoxia group, hypoxia and low dose of minocycline group (0.5 mu;mol/L), hypoxia and medium dose of minocycline group (5 mu;mol/L), and hypoxia and high dose of minocycline group (50 mu;mol/L). Real-time reverse transcriptionpolymerase chain reaction (RT-PCR) and immunohistopathological staining were used to measure the mRNA and protein expression of VEGFR-1 and VEGFR-2, respectively. Results RT-PCR showed that the expression of VEGFR-1 mRNA did not vary significantly between groups (F 24 h=0.17,F 48 h=1.53,F72 h=2.04;P＞0.05). Compared with hypoxia group, the expression of VEGFR-2 mRNA in all minocycline treated groups were significantly downregulated (low minocycline, medium minocycline, high minocycline: t=4.69, 20.16, 17.12; P＜0.001). The immunohistopathological study showed the cells with positive staining of VEGFR-1 can be observed in all groups, and the staining was relatively weak and mainly located in cell membrane and cytoplasm. The optical density value analysis showed that the protein expression of VEGFR-1 did not vary significantly between groups at all time points（F 24 h=0.251,F 48 h=0.340,F72 h=0.589;P＞0.05）. The VEGFR-2 positive staining cells were also observed in all groups, and the staining was relatively high. Brown staining particles of VEGFR-2 were observed in the cell membrane with minor staining particles in cytoplasm. The staining density of VEGFR-2 was significantly higher in hypoxia group than control group. Compared with the hypoxia group, the protein expression of VEGFR-2 in minocycline treated groups was significantly lower（F 24 h=19.147,F 48 h=14.893,F72 h==11.984; P＜0.05). Conclusion The expression of VEGFR-2 is upregulated in RF/6A, and minocycline somewhat shows an inhibition effect.
ObjectiveTo investigate the expressions of contactin-1 (CNTN-1), vascular endothelial growth factor-C (VEGF-C), and its receptor VEGFR-3 (Flt-4) in primary gastric cancer and to explore the relevance among them and their correlation with clinicopathologic features of gastric cancer. MethodsThe VEGF-C, VEGFR-3, and CNTN-1 protein expressions of tumor tissues and normal gastric mucosa tissues in 68 patients with primary gastric cancer were analyzed by immunohistochemistry. The Flt-4-positive vessel density (FVD) and lymphatic vessel density (LVD) were also analyzed by VEGFR-3positive and D2-40-positive staining, respectively. ResultsThe positivity rate of VEGF-C, VEGFR-3, and CNTN-1 protein expression in the primary tumor was 57.4% (39/68), 60.3% (41/68), and 55.9% (38/68), respectively, which was significantly higher than that in the normal gastric mucosa tissues 〔20.6% (14/68), 23.5% (16/68), and 16.2% (11/68)〕， P=0.000. The expressions of VEGF-C, VEGFR-3, and CNTN-1 protein were significantly correlated with TNM stage, lymphatic vessel invasion, and lymph node metastasis (Plt;0.05). The expression of CNTN-1 protein was significantly correlated with VEGF-C (r=0.372, P=0.002) and VEGFR-3 protein expression (r=0.308, P=0.011). In tumor tissues of sixtyeight patients the FVD was (10.41±9.38)/HP, which was significantly lower than LVD 〔(18.19±7.44)/HP〕, P=0.000. Elevated FVD and LVD was significantly found in patients with tumor characterized by later TNM stage, severer lymphatic vessel invasion, and severer lymph node metastasis (Plt;0.05). The FVD of tumor was significantly correlated with VEGF-C (P=0.029) and CNTN-1 protein expression (P=0.003). The LVD of tumor was not significantly correlated with CNTN-1 (P=0.727), VEGF-C (P=0.173), and VEGFR-3 protein expression (P=0.924). The patients with positive expression of VEGF-C, VEGFR-3, and CNTN-1 protein showed poorer prognosis (Plt;0.05). ConclusionsElevated expression of CNTN-1 protein is observed in primary gastric cancer and correlated with VEGF-C and VEGFR-3 protein expression, indicating that combined detection has great value in prediction of invasive potential and prognosis. VEGF-C-mediated CNTN-1 overexpression may promote lymphatic invasion via lymphangiogenesis pathway in patients with gastric cancer.
Objective To investigate the role of vascular endothelial growth factor-C (VEGF-C) and its receptors in the formation of lymphatic vessels and lymphatic metastasis in gastric cancer. Methods By the domestic and overseas literatures review, the expressions of VEGF-C and its receptors in gastric cancer, their role in tumor lymphatic metastasis and prospect in treatment of gastric cancer were summarized.Results There was a significant correlation between VEGF-C and its receptors and the formation of lymphatic vessels and lymphatic metastasis in gastric cancer. VEGF-C high expression might be an early event in lymphatic metastasis and could be considered as an independent predictive factor of lymphaticmicrometastasis. By inhibition of gastric cancer cell from secrete VEGF-C or blockage of the interaction of VEGF-C with VEGFR3, it was possible to inhibit tumor angiogenesis and the invasion and distant spread of cancer cells, thereby decreased mortality and improve survival. ConclusionVEGF-C and its receptors may promote the formation of lymphatic vessels and lymphatic metastasis in gastric cancer. It may be an effective way to gastric cancer for the treatments against VEGF-C and its receptors.
Objective To explore and evaluate the protective effects of soluble fms-like tyrosine kinase recptor-1(sFlt-1) gene 2-3 and 2-4 transcellular region on retinal vascular leakage and phosphatidyl inositol-3 kinase (PI3K)/Akt pathway under hypoxia and/or hyperglycemia. Methods The plasmids pcDNA3.1-EGFP/sFlt-1(2-3) and pcDNA3.1-EGFP/sFlt-1(2-4) were constructed.. Two of these plasmids with carboxy methylation glucan (CMD) magnetic particles were transfected into human umbilical vein endothelial cells (HUVEC), which were cultured under hypoxia and/or hyperglycemia. The blood retinal barrier was evaluated by Evans blue permeation (EBP). Then the expression of p-Akt mRNA and protein were detected by reverse transcriptionpolymerase chain reaction (RT-PCR) and Western blot separately. Results In the diabetic rabbits, The blood retinal barrier breakdown was detected by the retinal vascular leakage of EBP. The expression of p-Akt mRNA and protein in hypoxia and hyperglycemia groups were also obviously increased. These changes were largely prevented by transfection the plasmids pcDNA3.1-EGFP/sFlt-1(2-3) and pcDNA3.1-EGFP/sFlt-1(2-4) (P＜0.01 in both groups). Conclusion Both sFlt-1(2-3) and sFlt-1(2-4) can make the retinal blood vessels less leaky and may be beneficial in preventing vision loss from diabetic retinopathy.
Objective To compare the transfection effects on soluble fms-like tyrosine kinase receptor-1 (sFlt-1) gene (2-4 transcellular region) mediated by carboxymethylated dextran coated nanoparticle and lipofectamineTM2000.Methods The plasmid pcDNA3.1-EGFP/sFlt-1(2-4) was constructed and assessed by enzyme cut, electrophoresis, and genetic sequencing. Three groups were divided: nanoparticle group, lipofectamine group, and non-transfected group. Twenty-four and 48 hours after the transfection, the distribution of cellular green fluorescence was oberved under the inverted phase contrast fluorescence microscope; the expression rate of green fluorescence was measured by flow cytometry; the expression of sFlt-1(2-4)mRNA and the protein was detected by reverse transcriptionpolymerase chain reaction (RT-PCR) and Western blot; the growth of the cells was observed by methyl thiazolyl tetrazolium (MTT) colorimetry and the relative growth rate (RGR) of the cells in each group was calculated; the cellular apoptosis in each group was detected by Hoechst staining.Results The sequence of sFlt-1(2-4) gene was equal to 915 base pair (bp).The transfection rate was 45% in nanoparticle group and 21% in lipofectamine group; the difference between the two groups was significant (t=2.541，Plt;0.05). Forty-eight hours after the transfection, the expression of sFlt-1（2-4）mRNA and protein was obviously higher in nanoparticle group than that in lipofectamine group (t=2.454，2.398；Plt;0.05) . Twenty-four and 48 hours after the transfection,the difference of RGR of the cells between nanoparticle and non-transfected group was not significant（t=1.436，Pgt;0.05）; the RGR in lipofectamine group differed much from that in non-transfected and nanoparticle group (t=2.412，2.545; Plt;0.05) ; the difference of cellular apoptosis was not significant between nanoparticle and nontransfected group (t=1.436，Pgt;0.05), but significant between nanoparticle and lipofectamine group (t=2.236，Plt;0.05). Conclusion The transfection rate of sFlt-1(2-4) mediated by carboxymethylated dextran coated nanoparticle was higher than that mediated by lipofectamineTM2000.
【Abstract】Objective To investigate the role of VEGF and its soluble VEGF receptor ( sVEGFR-1) in pathogenesis of acute lung injury ( ALI) induced by immersion in seawater after open chest trauma. Methods Sixteen hybridized adult dogs were randomly divided into control group and seawater group. The control group only suffered from open chest trauma, whereas the seawater group were exposed to seawater after open chest trauma. Blood samples were collected at the 0, 2, 4, 6, 8 h after trauma for measurement of white blood cell count, arterial blood gas, plasma osmotic pressure ( POP) , electrolyte concentration, IL-8, vWF, VEGF and sVEGFR-1 levels. The lungs tissue and BALF was collected at 8 h after trauma. Pathological changes of the lung was observed under light microscope by HE staining. Meanwhile VEGF and sVEGFR-1 levels were measured in BALF and lung tissue homogenate. Total protein concentrations in plasma and BALF were measured to calculate the pulmonary penetration index ( PPI) . Results The lung of the seawater group showed interstitial mononuclear cell and neutrophil infiltration, interstitial edema, and vascular congestion. VEGF and sVEGFR-1 were significantly increased in the plasma, while VEGF was significantly reduced in the lung tissues and BALF. The levels of IL-1β, IL-8 and vWF, just as the level of VEGF, were significantly increased in the plasma. Meanwhile, the POP and electrolyte concentration were significantly increased. In the plasma, the responses of VEGFs during the early onset of ALI induced by immersion in seawater after open chest trauma were consistent with the POP and PPI. Conclusions High plasma levels and low BALF/ lung tissue levels of VEGFs is a distinguishing characteristic during the early onset of ALI induced by immersion in seawater after open chest trauma. VEGF may be a novel biomarker which has an important role in the development of ALI.
ObjectiveTo observe the stoichiometry of vascular endothelial growth factor receptor 2 (VEGFR2) on the retinal vascular endothelial cell membrane by single-molecule fluorescence imaging.MethodsRhesus monkey retinal vascular endothelial cells (RF/6A) were divided into blank control group (normal culture) and plasmid transfection group [transfected with VEGFR2-green fluorescent protein (GFP) recombinant plasmid]. The expression of GFP in the plasmid transfected group was observed by confocal microscope, and the expression of VEGFR2 in the cells was detected by real-time fluorescent quantitative polymerase chain reaction (qPCR) and Western blot. The fluorescence intensity distribution and bleaching steps of single VEGFR2-GFP molecule on the cell membrane were recorded by single-molecule imaging. The distribution of fluorescence intensity and the number of fluorescence bleaching steps of GFP were recorded.ResultsGFP green fluorescence was observed in the transfected cells 12 hours after transfection. qPCR results showed that the expression of VEGFR2 and GFP mRNA in the plasmid transfected group was significantly higher than that in the blank control group (t=11.240, 12.330; P＜0.001, 0.001). Western blot results showed that the expression of VEGFR2 protein in the plasmid transfected group was significantly higher than that in the blank control group (t=8.346, P＜0.01). The results of single-molecule imaging showed that the fluorescence intensity distribution of VEGFR2-GFP on the surface of RF/6A cell membrane without ligand stimulation was bimodal, in which monomer and dimer were 86.0% and 14.0% respectively. By counting the steps of GFP fluorescence bleaching, the proportions of receptor monomer, dimer, trimer, and tetramer were 81.4%, 12.9%, 5.5%, and 0.3% respectively.ConclusionIn the absence of ligands, VEGFR2 coexists in the form of monomers and dimers on the surface of RF/6A cell membrane, and monomers are dominant.
ObjectiveTo observe the effect of Delta-like ligand 4 (Dll-4) on the pathological structure of retina in early diabetic rats (DM) and its relationship with vascular endothelial growth receptor-2 (VEGFR-2).MethodsA total of 70 male Sprague-Dawley rats were randomly divided into normal group and DM group, with 10 and 60 rats in each group, respectively. The rats of DM group was induced by intraperitoneal injection of streptozotocin to established DM model. The rats with blood glucose recovery and death were excluded, and the final 60 rats were included in the statistics. Rats in the normal group were injected with an equal volume of citric acid-sodium citrate buffer. Rats in the DM group were divided into DM 1 month (DM 1m) group, DM 2 months (DM 2m) group, DM 3 months (DM 3m) group and DM 3m + Anti group, DM 3m + phosphate buffer solution (PBS) group by random number table method, and 10 rats in each group. In the DM 3m+Anti group, 4 μl of anti-Dll-4 polyclonal antibody was injected into the vitreous cavity, and the antibody concentration was 0.25 mg/ml. The DM 3m+PBS group was intravitreally injected with an equal volume of PBS. Five days after the injection, the rats were sacrificed. Rats in the DM 3m group and the normal group were not treated, and were sacrificed 3 months after the model was established. The structure and microvascular changes of the retina were observed by hematoxylin-eosin staining, and the total thickness of the retina was measured. The expression of Dll-4 and VEGFR-2 in the retina was detected by immunohistochemistry and fluorescence quantitative polymerase chain reaction (PCR). One-way analysis of variance was used to compare the expression of Dll-4 and VEGFR-2 in the retina of each group. The least significant difference t test was used to compare the two groups.ResultsLight microscopy showed that the retinal ganglion cells layer in the DM 3m group were obviously edematous, the inner and outer nuclear layers were thinner, the number of cells was reduced, the arrangement was disordered, the edema of outer plexiform layer was obvious, and the microvessels were abnormally dilated. In the DM 3m+Anti group, the edema of outer plexiform layer was lessened than that of the DM 3m group, and the other layers were not significantly different from the DM 3m group. Compared with the normal group, the total retinal thickness of the DM 3m group, the DM 3m+Anti group and the DM 3m+PBS group increased (t=5.596, 3.290, 4.286; P=0.000, 0.008, 0.002). Immunohistochemical staining showed that a small amount of Dll4 was positively expressed in the retinal ganglion cell layer of the normal group; a small amount of VEGFR-2 was positively expressed in the ganglion cell layer and the inner and outer nuclear layers. The positive expression of Dll-4 and VEGFR-2 in retinal vascular endothelial cells of DM 3m group increased significantly. The expression of Dll-4 was significantly decreased in the retinal layers and vascular endothelial cells of DM 3m+Anti group, while the expression of VEGFR-2 was significantly increased. There was no significant difference between the positive expression of Dll4 and VEGFR-2 in the DM 3m+PBS group and the DM 3m group. The results of real-time PCR showed that the relative expression of Dll-4 and VEGFR-2 mRNA in the DM 3m group was significantly higher than that in the normal group (t=6.705, 20.871; P＜0.05). Compared with DM 3m group, the relative expression of Dll-4 mRNA in DM 3m+Anti group decreased, and the relative expression of VEGFR-2 mRNA increased (t=2.681, 3.639;P＜0.05). The relative expressions of Dll-4 and VEGFR-2 mRNA in the DM 3m+PBS group and DM 3m group were not statistically significant (t=0.513, 0.657; P＜0.05).ConclusionsThe expression of Dll-4 in retinal vascular endothelial cells is gradually increased during the early retinopathy of DM rats. The expression of Dll-4 is inhibited, the expression of VEGFR-2 is up-regulated, and the plexus edema is alleviated.