Objective To investigate the effects of advanced glycation endproducts (AGEs) on proliferation of pericytes of bovine retinal capillary vessels and expression of transforming growth factor beta;(TGF-beta;). Methods The proliferation of pericytes detected by methyl thiazolyl tetrazolium (MTT) colorimetric assay, cellular cycle of pericytes was analyzed by flow cytometry was used to analyze cell, and TGF-beta; protein expression of pericytes was observed by immunofluorescent staining. Results AGEs inhibited the proliferation of pericytes of bovine retinal capillary vessels, stopped the cellular cycle of pericytes in synthesis phase (S phase), increased the number of apoptotic cells obviously (Plt;0.01), and promoted the expression of TGF-beta; proteinof perycytes. Conclusions AGEs may promote the apoptosis of pericytes by inhibiting the proliferation of pericytes to lead the decrease of pericytes number, and may accelerate diabetic retinopathy by promoting the expression of TGF-beta; protein of pericytes. (Chin J Ocul Fundus Dis, 2006, 22: 20-23)
Proliferative vitreoretinopathy (PVR) is a common complication and major cause of blindness of ocular trauma. Many cytokines, including vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF), participate in the process of the pathogenesis of traumatic PVR. VEGF competitively inhibits binding of PDGF to its receptor (PDGFRα), enables indirect activation of PDGFRα by non-PDGF ligands, resulting in reduced p53 expression, cell proliferation and migration, which is a key point in the pathogenesis of traumatic PVR.
The intervention therapy targeting vascular endothelial growth factor (VEGF) has become a specific and effective method for the treatment of diabetic retinopathy (DR). However, some patients did not respond or responded poorly to anti-VEGF therapy, and its effects of eliminating edema and improving vision appear to be unstable in the same patient. Hypoxia-inducible factor-1α (HIF-1α), an important upstream transcriptional regulator of VEGF, is an oxygen concentration-sensitive protein expressed in tissues under hypoxia. It can simultaneously target many downstream target genes except VEGF, such as placental growth factor and angiopoietin-like protein 4, to cause blood-retinal barrier damage and neovascularization, and thus participate in various pathological changes of DR to promote the occurrence and development of DR. Therefore, direct intervention of HIF-1α or targeting one or more downstream target genes regulated by HIF-1α to treat DR may have better efficacy. In the future, the development of effective and safe HIF inhibitors or anti-VEGF with HIF-1α other target gene inhibitors may have broader clinical application prospects.
Objective To observe the influence of rAAV-mediated antisense vascular endothelial growth factor (rAAV-aVEGF165) on the expression of retinal VEGF in diabetic rats. Methods 40 Sprague-Dawley rats induced diabetic rat model by intraperitoneal injection with streptozotocin (STZ). 32 rats were involved in study besides death and blood sugar recovery in experimental process, 16 spragud-Dawleg (SD) rats were received intravitreal injection with rAAV-aVEGF165 (1010 pfu) as experimental group, another group of Sprague-Dawleg (SD) rats were injected with phosphate buffered saline (PBS) as control group. One and five month after model establishment, the expression of retinal VEGF was evaluate by immunhistochemistry and Western blot; the retinal vasular was examined by transmission electron microscopy. Results On 1 month,the expression of retinal VEGF was lowest in each group. On 5 month, the expression of retinal VEGF was decreased in experimental group which compared to control, the difference are statistically significant （t=23.87,Plt;0.01）. The transmission electron microscopy results showed that retina has no obvious chages in experimental group, however,contral group showed fragmental thickening and splitting of basement membrane, swelling and deformation of endothelia cells,fingerlike prcess into the capillary cavity,and uneven distibution of heterochromatin in pericytes. Conclusion rAAV-aVEGF165 can reduce the expression of retinal VEGF thereby preventing occurrence and development of diabetic retinopathy. rAAV is an effective vectors of eye antisense gene. （Chin J Ocul Fundus Dis，2008，24：255-258）
Objective To investigate the effect of batroxobin on the blood-retinal barrier (BRB) and vascular endothelial growth factors (VEGF) in diabetic rats. Methods Sixty Sprague-Dawley rats were used to establish diabetic models by intraperitoneal injecting with streptozotocin (60 mg/kg), and were divided into 3 groups: diabetic group (n=20), batroxobin (40 mg/kg) group (n=20) and batroxobin (20 mg/kg) group (n=20). Twenty-five else rats were in control group. All of the rats were executed 7 days later. The function of BRB was observed by Evans blue method. Results concentration of VEGF protein was detected by enzyme-linked immunoabsorbert assay (ELISA). The results of each group were compared. Results The content of BRB leaked into retina was obvious lower in the control group than which in the other 3 diabetic groups（Plt;0.01）. There was no significant difference of the content of Evans blue between the two groups with different dosage of batroxobin (P＞0.05). The content of Evans blue was lower in the 2 diabetic groups with different dosage of batroxobin than which in the control group (Plt;0.05). The content of VEGF in retina was obviously lower in control group and 2 diabetic groups with different dosage of batroxobin than which in the diabetic group (Plt;0.01), and obviously lower in batroxobin (40 mg/kg) diabetic group than which in the control group (P＝0.01). The content of VEGF in control group and batroxobin (20 mg/kg) diabetic group (P＝0.06) didnprime;t differ much, which occurred similarly in batroxobin diabetic groups with different dosage (P＝0.78). Conclusions Batroxobin may alleviate the damage of function of BRB in diabetic rats and reduce the expression of VEGF, which suggests that batroxobin can protect the function of BRB to a certain extent. (Chin J Ocul Fundus Dis, 2006, 22: 16-19)
Objective To determine the association between the geneti c polymorp hisms of vascular endothelial growth factor (VEGF) gene and the prognosis for retinopathy of prematurity (ROP) in Chinese. Methods Twenty infants with threshold ROP who had undergone retinal photocoagulation were in the treated group and 20 infants with self-regressed ROP without any treatment were in the control grou p . In the two groups, all the infants had oxygen-breathing history and the sex a n d gestational age were all suitable to be compared, except birth weight. Polymer ase chains reaction-restriction fragment length polymorphism was used to determine the frequencies of VEGF genes in the two groups. Results The frequencies of +405C allele were higher in the treated group than those in the control group (P＜0.05). The frequencies of the VEGF-460T/C and +936C/T ploymorphisms were similar in both groups (P＞0.05). Conclusions The +4 05C/G ge netic polymorphisms of VEGF may correlate to the prognosis of ROP. The carriers of +405CC allele are more susceptible to ROP.
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 effect of conditional knocking out (KO) vascular endothelial growth factor (VEGF) gene on the mouse model of oxygen induced retinopathy (OIR).MethodsThe conditional VEGF KO mice were generated using Cre-Loxp technology, resulting in the deletion of VEGF in a portion of Müller cells permanently in mouse retina. Cre positive was CKO mice, Cre negative was NKO mice. OIR was induced by keeping mice in 75% oxygen at postnatal 7 days (P7) to P12 and in room air from P12 to P17 (each 20 mice for CKO and NKO, respectively). The mice mortality was analyzed. At day P17, the percentage of retinal avascular area was calculated using retinal flat-mounting with fluorescence angiography, the number of vascular endothelial cell nucleus breaking through retinal inner limiting membrane was counted with hematoxylin eosin (HE) staining of retinal sections, and the expression of hypoxia-inducible factor-1α (HIF-1α) was detected by immunofluorescence analysis. ResultsDuring the development of OIR, the mortality rate of CKO mice (65.00%) was higher than that of NKO mice (30.00%) with the significant difference (x2=4.912, P=0.027). At day P17, all the mice retinas were harvested. The retinal fluorescence angiography displayed that the normal retinal vascularization of CKO mice was delayed, and large avascular areas were observed. Meanwhile, rare new vascular plexus was found in CKO mice and the thickness of whole retina decreased dramatically. In contrast, NKO mice developed larger area of normal retinal vascular network structure with higher blood vessel density and more new vascular plexus with obvious fluorescein leakage. The percentage of avascular area in CKO mice [(28.31±11.15)%] was higher than NKO mice [(16.82±7.23)%] with the significant difference (t=2.734, P=0.014). The HE staining of retinal sections indicated smaller counts of vascular endothelial cell nucleus breaking through retinal inner limiting membrane in CKO mice (26.10±6.37) when compared to NKO mice (28.80±7.59) , the difference was significant (t=2.437, P=0.016). The immunofluorescence analysis showed stronger expression of HIF-1α in CKO mice than NKO mice, which was mainly located in the retinal ganglion cell layer.ConclusionsThe local VEGF gene knockout partially inhibits retinal neovascularization in OIR mice. However, it also suppresses the normal retinal blood vascular development with a decrease of OIR mice survival ability.
Anti-vascular dndothelial growth factor (VEGF) drugs have open up a new treatment channel for ocular neovascular diseases. A lots of clinical data has proved that anti-VEGF drugs are effective and safe. But we should also notice that long-term and excessive usage of anti-VEGF drugs brings some new problems and complications, and even affect the normal ocular physiological process of the angiogenesis and retinal blood flow. So, it is necessary to pay attention to the problems and potential risks of excessive usage of anti-VEGF therapies for ocular neovascular disease.
ObjectiveTo investigate the expression and relation of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in rats with diabetic retinopathy.MethodFifty-five Wistar rats were randomly divided into the control group (10 rats), and 1, 3, and 5-month-diabetes group (15 rats in each diabetes group), and the diabetic models were set up. The expressions of VEGF and bFGF were detected by situ hybridation and immunohistochemistry on retinal paraffin sections.ResultsThe results of situ hybridation showed that expression of bFGF was found in 3-month-deatbtes group with the percentage of 77.8%, and 88.9% in 5-month-deatbtes group; the positive expression of VEGF was not found in 3-month-deatbtes group but in 5-month-deatbtes group with the percentage of 66.7%. Immunohistochemistry indicated that the positive expression of bFGF started in 3-month-deatbtes group with the percentage of 55.6%, and 88.9% in 5-month-deatbtes group; the percentage of the expression of VEGF was 33.3% in 3-month-deatbtes group and 88.9% in 5-month-deatbtes group.ConclusionThe expression of VEGF occurs after the expression of bFGF in rats with DR.(Chin J Ocul Fundus Dis, 2005,21:37-40)