Objective To observe the expression of p53, bcl-2 genes, vascular endothelial cell growth factor（VEGF）, basic fibroblast growth factor（bFGF）, insulin-like growth factor-I （IGF-I）, and the receptors of these factors of retinal vascular endothelial cells (VECs) of 1- to 20-week diabetic rats, and the relationship between the expressions and cell cycle arrest.Methods Retinal sections of diabetic rats induced by alloxan were immunohistochemically stained and observed by light microscopy (LM) and electron microscopy (EM). Dot blotting and Western blotting were used to determine the expression of mRNA, proteins of p53 and bcl-2. Results Under LM, immunohistochemical positive expression of p53 and bcl-2 were found on the vessels of ganglion cell layer and inner nuclear layer of retinae of 8- to 20-week diabetic rats; under EM, these substances were observed depositing in VECs. The retinal VECs also expressed VEGF, bFGF, IGF-I and their receptors. There was no positive expression of other cell types in these retinae, all cell types of retinae in control group, or all cells of retinae of diabetic rats with the course of disease of 1 to 6 weeks. The result of dot blotting revealed that retinal tissue of 20-week diabetic rat expressed p53 and bcl-2 mRNA, and the result of Western blotting revealed that they also expressed p53 and bcl-2 proteins. But retinal tissues of control group did not. Positive expression of bax was not found in the retinae in control group or 1- to 20-week diabetic rats. Conclusion p53, bcl-2 may introduce cell cycle arrest of VECs of retinae in 8- to 20-week diabetic rats. High glucose might stimulate the expression of VEGF, bFGF, IGF-I and their receptors, and the growth factors may keep VECs surviving by self-secretion. (Chin J Ocul Fundus Dis，2003，19：29-33)
ObjectiveTo observe the expression of Rap1, guanosine triphosphate-Rap1 (GTP-Rap1), vascular endothelial growth factor (VEGF) and β-catenin in experimental choroidal neovascularization (CNV).MethodsForty-two brown Norwegian rats were randomly divided into a blank control group (7 rats) and a model group (35 rats). Both eyes were enrolled. The CNV model was established by holmium ion laser photocoagulation in the model group. At 3, 7, 14, 21, and 28 days after photocoagulation, fluorescein fundus angiography (FFA) and choroidal vascular smear were performed to observe the degree of fluorescein leakage and CNV area in rats; Western blot and real-time quantitative polymerase chain reaction (RT-PCR) were used to detect the expression of Rap1, GTP-Rap1, VEGF, β-catenin and mRNA in CNV.ResultsThe results of FFA examination showed that a large disc-shaped fluorescein leaked in the photo-condensation spot 14 days after photocoagulation. Laser confocal microscopy showed that compared with 7 days after photocoagulation, CNV area increased at 14, 21, 28 days after photocoagulation, and the difference were statistically significant (t=3.725, 5.532, 3.605;P＜0.05). Western blot showed that there was no significant difference in the relative expression of Rap1 protein in CNV at different time points after photocoagulation between the two groups (P=0.156). Compared with the blank control group, the relative expression of GTP-Rap1 protein was significantly decreased, the relative expression of VEGF and β-catenin protein were significantly increased in the model group (P=0.000). The results of RT-PCR showed that there was no significant difference in the relative expression of Rap1 mRNA at different time points after photocoagulation between the two groups (P=0.645), but there were significant difference in the relative expression of β-catenin mRNA (P=0.000). At 7, 14, 21 and 28 days after photocoagulation, there were significant difference in the relative expression of GTP-Rap1 and VEGF mRNA between the two groups (P=0.000).ConclusionsThe expression of GTP-Rap1 in experimental CNV is significantly lower than that in normal rats.
Objective To investigate the expression of pigment epitheliumderived factor (PEDF) and vascular endothelial growth factor (VEGF) in choroidal melanoma. Methods The expression of VEGF and PEDF protein in fifty-eight cases of paraffinembeded choroidal melanoma samples was measured by immunohistochemistry, the expression of PEDF mRNA in thirtynine choroidal melanoma samples was assayed by in situ hybridization. Results PEDF protein was detected in 13/58 cases (22.4%) of choroidal melanoma, the positive rate in nonsclerainvasion group (12/38, 31.6%) was higher (Plt;0.05) than that in sclerainvasion group (1/20, 5%). VEGF protein was detected in 43/58 cases (64%) of choroidal melanoma, the positive rate in nonsclerainvasion group (25/38, 65.8%) was lower (Plt;0.05) than that in sclerainvasion group (18/20, 90%). The expression of PEDF mRNA was detected in 18/39(46.2) cases, the positive rate in nonsclerainvasion group was higher (Plt;0.05) than that in sclerainvasion group. Conclusions Imbalanced expression of VEGF and PEDF in choroidal melanoma may play a key role in the angiogenesis, tumor progression and metastasis.
Objective To verify the effect of Evans blue dye on determining the retina blood vessel leakage． Methods Male Sprague-Dawley rats were used in this study． The VEGF induced retinal blood vessel leakage was checked with Evans blue dye． Then the bloodretina barrier breakdown of 1 week diabetic animals was quantified with Evans blue．The dye was extracted from retina by formamide and the extraction was checked with spect rophotometer． Evans blue leakage was normalized against wet or dry retina weight． Results The retinal Evans blue content of eyes treated with VEGF was remarkably higher than that of the controls (n=17 ,Plt;0．0001)． And the eyes of 1 week diabetic duration animals had more Evans blue dye than that of the normal controls (Plt;0．05)． Conclusion Evans blue dye is a sensitive tracer in quantitatively diagnosing the blood retina barrier breakdown． (Chin J Ocul Fundus Dis, 2001,17:221-223)
Objective To investigate if lactic acid can promote the expression of vascular endothelial growth factor (VEGF) in the rat retinal explants.Methods The retinas of two-week neonatal SD rats were placed onto the culture plate inserts and incubated with Dulbeccoprime;s modified Eagleprime;s medium （DMEM） plus 2% fetal bovine serum (FBS) containing 10,20,30 mmol/L of lactic acid, respectively. Each group had 24 retinas. At 24 hours after incubation, the retinas were sectioned for light microscopy and the expression of VEGF was measured by real time PCR and Western blot. Results The cultured retinas maintained intact construction, and no cytolysis and apoptosis were observed under light microscope. RT-PCR showed the levels of VEGF mRNA were 0.74plusmn;0.06 for 10 mmol/L lactic acid group, 0.99plusmn;0.12 for 20 mmol/L group, and 1.45plusmn;0.17 for 30 mmol/L group respectively. VEGF expression was 0.34plusmn;0.15 for 10 mmol/L, 0.54plusmn;0.16 for 20 mmol/L, and 0.93plusmn;0.23 for 30 mmol/L group respectively by Western blot. Both PCR and Western blot showed 30 mmol/L of lactic acid significantly increased the levels of VEGF mRNA and VEGF expression. Conclusion The induction of retinal VEGF by lactic acid is concentration-dependent.
ObjectiveTo observe the expression of connective tissue growth factor (CTGF) in injured model of retinal pigment epithelial (RPE) cells and the promoting effect of CTGF on migration of RPE cells.MethodsCultured monolayer-confluent human RPE cells were scraped with a trephine and a cotton stick, and set up the injured model of RPE cells with round scraped area. Immunohistochemistry and in situ hybridization(ISH) were used to detect the expression of CTGF protein and mRNA in injured RPE cells at distinct time points after injury. The number of RPE cells migrated to injured area was measured and the effect of CTGF on migration of RPE cells and the effect of dexamethasone (DEX) on the promoting process of CTGF were observed.ResultsThe results of immunohstochemistry and ISH indicated the weak positive expression of CTGF in RPE cells at the edge of scrape 6 hours after injury, and the positive expression increased gradually as time goes by after the injury. Strong positive expression of CTGF in RPE cells at the edge of scrape was found 24 and 48 hours after injury. Rebuilt human CTGF stimulated migration of RPE cells in a dose-depended manner, and DEX significantly inhabited the migration.ConclusionCTGF involves in the procedure of repair of injury of RPE cells, which may play an important role in the pathogenesis of intraocular proliferative diseases such as proliferative vitreoretinaopathy.(Chin J Ocul Fundus Dis, 2005,21:306-309)
Objective To observe the effect of celecoxib on the expression vascular endothelial growth factors (VEGF) in diabetic rats. Methods Thirty-six wistar rats were used to establish the diabetic models by intraperitoneal injection with streptozotocin. The diabetic rats were divided into 2 groups: diabetic group (n=18) and celecoxib group (n=18). Celecoxib (50 mg/kg) was administered orally to the rats in celecoxib group and the physiological saline with the same volume was given orally to the rats in diabetic group. Eighteen else rats were in normal control group. All of the rats were executed 3 months later. The expression of VEGF protein was detected by immunohistochemistry method. Reverse transcription-polymerase chain reaction（RT-PCR） analysis was used to examine the expression of retinal VEGF mRNA and cyclooxygenase-2 mRNA. Results Lower positive expression of VEGF mRNA and cyclooxygenase-2 mRNA, weakly positive action of immunohistochemistry of VEGF, and lower expression of VEGF protein were detected in normal control group; in the diabetic group, the expression of VEGF mRNA and cyclooxygenase-2 mRNA increased obviously comparing with which in the control group (Plt;0.05), and the bly positive action of immunohistochemistry of VEGF and increased expression of VEGF protein were detected (Plt;0.01); in celecoxib group, the expression of VEGF mRNA was lower than that in the diabetic group (Plt;0.05), the expression of cyclooxygenase-2 mRNA didnprime;t decrease much (Pgt;0.05), the positive action of immunohistochemistry of VEGF decreased, and the expression of VEGF protein decreased (Plt;0.01). Conclusion By inhibiting the activation of cyclooxygenase-2, celecoxib can inhibit the expression of retinal VEGF mRNA and protein in diabetic rats induced by streptozotocin. (Chin J Ocul Fundus Dis,2007,23:265-268)
Objective To observe the effects of the bone marrow mesenchymal stem cells (BMSCs) on the expression of neurotrophic factor protein gene in the retinal detachment (RD) rabbits. Methods 60 healthy rabbits were randomly divided into control group (group A), retinal detachment with PBS group (group B), retinal detachment with BMSCs group (group C), 20 rabbits in each group. RD model were established for rabbits in group B and C. 10 μl PBS was injected into the subretinal space of rabbits in group B, while 10 μl CM-Dil labeled BMSC PBS was injected into subretinal space of rabbits in group C. The rabbits in the group A received no treatment. At 1, 2 and 4 weeks after modeling, the mRNA expression of basic fibroblast growth factor (bFGF), brain derived neurotrophic factor (BDNF) and ciliary neurotrophic factor (CNTF) were measured by real-time quantitative PCR. Results At 1, 2 and 4 weeks after modeling, the mRNA expression of bFGF, BDNF, CNTF on retinal tissue were increased significantly in group C as compared with group A and B (P < 0.01). At 1 week after modeling, the mRNA expression of bFGF and CNTF on retinal tissue were increased significantly in group B as compared with group A, the mRNA expression of BDNF on retinal tissue in group B was similar with group C. At 2 and 4 weeks after modeling, the mRNA expression of bFGF, BDNF, CNTF were decreased in group B as compared with group A. Conclusion Subretinal transplantation of BMSC can increase the mRNA expression of bFGF, BDNF and CNTF on retinal tissue in RD rabbits.
ObjectiveTo investigate the role of sonic hedgehog (Shh) signal transduction pathway in the expression of vascular endothelial growth factor (VEGF) under hypoxia in cultured human retinal pigment epithelial (hRPE) cells. MethodsARPE-19 were cultured and divided into normal ARPE-19 (Cont) and hypoxia group (100 μmol/L CoCl2 Cobalt Chloride +ARPE-19); hypoxia group was further divided into CoCl2 group, cyclopamine group (CYA) and dimethyl sulfoxide (DMSO) group. 20μmol/L cyclopamine was added to the CYA group 1 hour before hypoxia, 1‰DMSO was added into DMSO group at the same time. The hRPE cells were cultured under hypoxia for 4, 8, 12, 24 hours. The expression of Shh and VEGF were determined by Real-time fluorescent quantitate PCR (RT-PCR). The amount of VEGF in the hRPE-conditioned supernatant was measured using enzyme linked immunosorbent assay (ELISA) at 4, 8, 12, 24 hours, respectively. ResultsRT-PCR tests showed that the level of Shh and VEGF of hRPE was time dependently increased (Shh: F=45.260, P=0.001; VEGF: F=264.938, P=0.001). The level of Shh and VEGF of hRPE in the group treated with cyclopamine was decreased (P < 0.01). ELISA tests showed that the amount of VEGF in hRPE supernatant was significantly increased in time-dependent manner (F=3 156.676, P=0.001), and it was down-regulated by cyclopamine under hypoxia (P < 0.01). ConclusionShh signal transduction pathway could play a role in the VEGF expression induced by hypoxia in hRPE cells.
ObjectiveTo observe the expression of vascular endothelial growth inhibitor (VEGI, TL1A), vascular endothelial growth factor (VEGF), tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in diabetes rats' serum, vitreous and retina, and discuss the role of VEGI in the pathogenesis of diabetic retinopathy (DR). MethodsA total of p70 adult male Wistar rats were randomly divided into 4 groups, the control group (10 rats), the diabetes mellitus (DM) 1 month group (20 rats), the DM 3 month group (20 rats) and the DM 6 month group (20 rats). Cytokines of serum and vitreous were determined by enzyme-linked immunosorbent assay (ELISA), and the concentrations of the cytokines in the retina were determined by immunohistochemistry on paraffin retinal sections. Hematoxylin-eosin (HE) staining of retina was used to estimate the pathological change of DR. The results were analyzed by one-way analysis of variances, independent samples t-test and LSD test. ResultsThe serum TL1A levels of the control group, the DM 1 month group, the DM 3 month group and the DM 6 month group rats were (92.09±2.05), (118.36±8.30), (85.90±7.51) and (78.90±4.88) ng/L respectively, the level of TL1A in serum of the DM 1 month group, the DM 3 month group and the DM 6 month group were significantly lower than that of the control group (F=77.405, P < 0.05). The concentration of serum TNF-α and IL-1β increased after DM model was established (F=3.508, 15.416; P < 0.05); the VEGF level in serum showed no difference between the groups (F=1.242, P > 0.05). The vitreous TL1A levels of the control group, the DM 1 month group, the DM 3 month group and the DM 6 month group were (91.50±8.18), (67.03±6.74), (47.44±4.92) and (46.01±4.62) ng/L respectively, every DM groups showed significant difference with the control group (F=114.777, P < 0.05); VEGF level in vitreous increased from 1 month after DM model was established (F=8.816, P < 0.05); TNF-α and IL-1β level in vitreous also showed an upward tendency (F=4.392, 3.635; P < 0.05). Paraffin section immunohistochemistry showed that the absorbance (also called optical density) of TL1A of the DM 1 month group and the DM 3 month group were significantly lower than that of the control group (t=6.851, 6.066; P < 0.05), but the DM 6 month group showed no difference with the control group (t=1.401, P > 0.05); the level of VEGF and TNF-α in DM groups were higher than that of the control group (tVEGF=-4.709, -16.406, -9.228; tTNF-α=-4.703, -6.583, -17.762; P < 0.05); the level of IL-1β were significantly higher in the DM 1 month group and the DM 6 month group (t=-4.108, -3.495; P > 0.05); but the DM 3 month showed no difference with the control group (t=-0.997, P > 0.05). HE staining of retina showed that the retina of the control group and the DM 1 month group had normal retinal structures, the DM 3 month group had retinal edema and disorganization, the DM 6 month group had severe retinal edema, deep stain of ganglion cells, and more neovascularization in inner plexiform layer. ConclusionVEGI is involved in the pathogenesis of DR, and it might interacts with VEGF, TNF-α and IL-1β to affect the development of DR.