ObjectiveTo investigate the effects and mechanisms of G protein-coupled receptor 91 (GPR91) on blood-retinal barrier (BRB) in diabetic rats. MethodsA lentiviral vector of shRNA targeting rat GPR91 and scrambled shRNA were constructed. Healthy male Sprague-Dawley (SD) rats were selected in this study. The 60 rats were randomized into 4 groups and treated as follows:(1) control group (Group A, n=15), the rats received injections of an equal volume of 0.1% citrate buffer; (2) streptozocin (STZ) group (Group B, n=15), the rats received injections of STZ; (3) LV.shScrambled group (Group C, n=15), diabetic rats received an intravitreal injection of 1 μl 1×108 TU/ml scrambled shRNA lentiviral particles at 2 weeks after the induction of diabetes; (4) LV.shGPR91 group (Group D, n=15), diabetic rats received an intravitreal injection of 1 μl 1×108 TU/ml pGCSIL-GFP-shGPR91 lentiviral particles. At 12 weeks after intravitreal injection, immunohistochemistry and Western blot were used to assess the expression of GPR91, p-extracellular signal-regulated kinase(ERK)1/2, t-ERK1/2, p-Jun N-terminal kinase (JNK), t-JNK, p-p38 mitogen-activated protein kinase (MAPK) and t-p38 MAPK. Haematoxylin and eosin (HE) staining and Evans blue dye were used to assess the structure and function of the retinal vessel. Immunohistochemistry enzyme-linked immunosorbent assay (ELISA) was used to test the protein level of VEGF. ResultsImmunohistochemistry staining showed that GPR91 was predominantly localized to the cell bodies of the ganglion cell layer. Western blot showed that GPR91 expression in Group D decreased significantly compared with Group C (F=39.31, P < 0.01). HE staining showed that the retina tissue in Group B and C developed telangiectatic vessels in the inner layer of retina, while the telangiectatic vessels attenuated in Group D. It was also demonstrated in Evans blue dye that the microvascular leakage in Group D decreased by (33.8±4.11)% compared with Group C and there was significant difference (F=30.35, P < 0.05). The results of ELISA showed the VEGF secretion of Group B and C increased compared with Group A and the VEGF expression in Group D was significantly down regulated after silencing GPR91 gene (F=253.15, P < 0.05).The results of Western blot indicated that compared with Group A, the expressions of p-ERK1/2, p-JNK and p-p38 MAPK were significantly upregulated (q=6.38, 2.94, 3.45;P < 0.05). Meanwhile, the activation of ERK1/2 was inhibited by GPR91 shRNA and the difference was statistically significant (F=22.50, P < 0.05). ConclusionsThe intravitreal injection of GPR91 shRNA attenuated the leakage of BRB in diabetic rats. GPR91 regulated the VEGF release and the leakage of BRB possibly through the ERK1/2 signaling pathway.
Objective Methods Ninety male Wister rats were randomly divided into normal control group, diabetic group and FTY720 group, thirty rats in each group. Diabetes was induced by giving a single intraperitoneal injection of streptozocin. FTY720 group was administered with FTY720 at a dose of 0.3 mg/kg by oral gavage daily for 3 months after establishment of diabetes. All rats were used for experiments following intervention for 3 months in FTY720 group. Immunohistochemical staining was used to observe the expression and distribution of intercellular adhesion molecule (ICAM-1) and vascular cell adhesion molecule (VCAM-1), and the positive cells were counted. Real-time reverse transcription PCR was used to measure mRNA expression of ICAM-1 and VCAM-1. Fluorescein isothiocyanate-Concanavalin A perfusion was used to detect retinal leukocytes adhesion. Evans blue (EB) perfusion was used to analyze retinal vascular permeability. Immunofluorescence staining was used to detect retinal inflammatory cells infiltration. Results In diabetic group, both ICAM-1(t=12.81) and VCAM-1 (t=11.75) positive cells as well as their mRNA expression (t=16.14, 9.59) were increased compared with normal control group, with statistical significance (P < 0.05). In FTY720 group, both ICAM-1(t=-9.93) and VCAM-1 (t=-6.61) positive cells as well as their mRNA expression (t=-15.28, -6.10) were decreased compared with diabetic group, with statistical significance (P < 0.05). Retinal leukocytes adhesion (t=16.32) and EB permeability (t=17.83) were increased in diabetic group compared with normal control group, while they were decreased in FTY720 group compared with diabetic group(t=-9.93, -11.82),with statistical significance (P < 0.05). There were many CD45 positive leukocytes infiltration in retina of diabetic group, including CD11b positive macrophage/activated microglia, while both of them were little in FTY720 group. Conclusions FTY720 can decrease retinal leukocytes adhesion, reduce retinal vascular permeability and inflammatory cells infiltration, which is associated with down-regulation of ICAM-1 and VCAM-1.
Objective To observe the effect of different concentration netrin-1 on retinal vascular permeability in diabetes mellitus (DM) rats. Methods Eighty adult Sprague-Dawley rats were randomly divided into 8 groups, 10 rats in each group, including normal control group (group A), normal＋balanced salt solution (BSS) group (group B), normal＋netrin-1 (500 μg/ml) group (group C) and DM group (50 rats in 5 sub-groups). DM rats were induced by intraperitoneal injection of streptozocin. Three months after intraperitoneal injection, 10 DM rats in the control group were injected with BSS (group D). Forty DM rats were injected with 5 μl of different concentrate netrin-1, and were divided into DM+netrin-1 10 μg/ml group (group E), DM+netrin-1 50 μg/ml group (group F), DM＋netrin-1 100 μg/ml group (group G), DM＋netrin-1 500 μg/ml group (group H) according to the different concentration. Non-DM rats in group C were injected with netrin-1 500 μg/ml. The expression of occludin was determined by immunohistochemistry for protein, and by real-time fluorescence quantitative reverse transcription polymerase chain reaction for mRNA level. Retinal vascular permeability was measured by Evans blue infusion. Results The expression of occludin protein and mRNA in group D were less than group A (t=27.71, 8.59;P=0.00, 0.00). However, the retinal vascular permeability increased in group D (t=?42.72,P=0.00). The expression of occluding protein, occludin mRNA and retinal vascular permeability showed significant differences between group D, E, F, G and H (F=146.31, 16.54, 67.77;P=0.00, 0.00, 0.00). Compared the group B with group C, there was no significant differences between the expression of occludin protein, occludin mRNA and the retinal vascular permeability (t=?1.13, 0.93, 1.04;P=0.27, 0.36, 0.31). The concentrate of netrin-1 showed a significant positive correlation to the expression level of occludin and occludin mRNA (r=0.73, 0.81;P=0.00, 0.00), but negative correlation to the vascular permeability (r=?0.61,P=0.00). Conclusion Netrin-1 can reduce the DM rats' retinal vascular permeability, which depended on the concentration of netrin-1.
Objective To observe the morphological changes of dendrite and soma in retinal ganglion cells (RGCs) which subsisted in early diabetic rats. Methods The RGCs of 3-months-course diabetic rats and coeval normal rats were marked by gene gun techniques. To collect RGCs photographs by Leica microscope with Z axis and CCD camera；to observe the changes of diameter, variance of structural features in dendritic field and somata after classification which according to the size and morphology. Thy-1 antibody marks on the retinal RGCs, taking a photograph under fluorescent microscope, counting the changes of retinal RGCs density in early diabetic rat. Results In three-month diabetic rats,the density of retinal RGCs was decreased obviously. Morphological changes of RGCs in the dendritic fields were observed with gene gun technique. There was no severe variation in all kinds of the bole of cell dendrite, in which some only showed crispation partially and sparseness also twisting in the dendritic ramus. The mean diameter of dendritic field and soma in class A of diabetic rats was (401plusmn;86) mu;m, the mean diameter of dendritic field in control group was (315plusmn;72) mu;m,compared with each other, there is statistically significant differences (t=21.249，Plt;0.001); the mean diameter of soma in class A of diabetic rats was (24plusmn;6) mu;m, the mean diameter of soma in control group was (22plusmn;5) mu;m, compared with each other, there is no statistically significant differences (t=0.927，Pgt;0.05); the mean diameter of dendritic field and soma in class B of diabetic rats were (170plusmn;36)、(14plusmn;2) mu;m respectively, in control group were (165plusmn;36)、(16plusmn;2) mu;m, the mean diameter of dendritic field and soma in class C of diabetic group were(265plusmn;78)、(17plusmn;5) mu;m respectively, in control group were (251plusmn;57)、(17plusmn;4) mu;m , compared with each other, there are on statistically significant differences(t=1.357，0.798，0.835，1.104，Pgt;0.05). Conclusions In short-term diabetes, the survived RGCs show good plasticity in adult diabetic rats, especially in class A. The changes of dendrites were more sensitive than the soma, which could be the leading index of the morphologic changes of RGCs in the early stage. The good plasticity showed by the RGCs and the time window from changing in dendrite to cell death provide us many evidences not only for the research but also for the nerve protection in clinic. (Chin J Ocul Fundus Dis,2008,24:249-254)
ObjectiveTo observe the effect of interleukin (IL) 10 modified endothelial progenitor cells (EPC) in diabetic retinopathy (DR). MethodsEPC cells were collected and cultivated from the bone marrow of rats and identified by immuno-fluorescence staining. EPC cells were infected with lentivirus (LV) of EPC-LV-IL10-GFP (EPC-LV-IL10-GFP group) or EPC-LV-NC-GFP (GFP group). EPC cells without lentivirus infection was the EPC group. Enzyme-linked immuno sorbent assay (ELISA) was used to measure the concentrations of tumor necrosis factor (TNF)-α, IL10, IL8 and vascular endothelial growth factor (VEGF) in the supernatant of these three groups. 168 male Wistar rats were divided into normal control group (28 rats), diabetes mellitus (DM) group (28 rats), DM-blank control group (56 rats) and DM-intervention group (56 rats). DM was introduced in the latter 3 groups by streptozotocin intravenous injection. Three months later, the rats in the DM-blank control group and DM-intervention group were injected with EPC-LV-NC-GFP or EPC-LV-IL10-GFP by tail vein, respectively. Immunohistochemistry was used to observe the GFP expression in rat retinas. The blood-retinal barrier breakdown was detected by Evans blue (EB) dye. The retinal histopathologic changes were observed by transmission electron microscope. The mRNA level of VEGF, matrix metallproteinases-9 (MMP-9), angiopoietin-1 (Ang-1), inducible nitric oxide synthase (iNOS) and endothelial nitric oxide synthase (eNOS) in retina were measured by reverse transcription-polymerase chain reaction (RT-PCR). ResultsELISA showed that the levels of TNF-αand IL8 in the supernatant significantly decreased, while the levels of IL10 and VEGF increased (P < 0.05) in EPC-LV-IL10-GFP group. GFP expressed in the retina of blank control group and intervention group, mainly in the ganglion cell layer, inner nuclear layer and outer plexiform layer. The retinal blood vessel pathological change and EB permeability significantly decreased in intervention group compared with DM group (P < 0.05), and blank control group (P < 0.05). RT-PCR revealed that the mRNA level of VEGF, MMP-9 and Ang-1 significantly increased, and eNOS decreased in DM group compared to the normal control group (P < 0.05). The mRNA level of VEGF and iNOS decreased, eNOS increased while Ang-1 and MMP-9 had not changed in DM-blank control group and DM-intervention group compared with DM group (P < 0.05). ConclusionsIL10 modified EPC can improve the inflammative microenvironment and suppressed the pathogenesis of DR. Furthermore, EPC transplantation can increase the number of EPC and exerted their effect.
Objective To observe the effects of high concentr at ion glucose on the calcium-activated potassium channel of rabbits′ retinal Müller cells. Methods The rabbits′retinal Müller cells were cultured in vitro under the condition of high concentration glucose, and identified by immunohistochemical staining and transmission electron microscopy. Patch-clamp technique was used to observe the changes of the calcium-activated potassium channel of retinal Müller cells caused by high concentration glucose at different time.Results High concentration glucose could inhibit the calcium-activated potassium channel of cultured retinal Müller cells in a time-dependent manner. Conclusion High concentration glucose may reduce the biological functions of Müller cells by inhibiting calcium-activated potassium channel. (Chin J Ocul Fundus Dis，2003，19：164-167)
ObjectiveTo observe the effect of tert-butyl hydroquinone (tBHQ) on type 2 diabetic rats retinal nuclear factor E2-related factor 2 (Nrf2) and hemeoxygenase-1 (HO-1). Methods60 Sprague Dawley rats were randomly divided into normal control group (NC group, n=20) and model group (n=40). The rats in model group were intraperitoneal injected with streptozotocin (30 mg/kg) to establishing type 2 diabetic mellitus (DM). There were 35 rats successfully established and they were randomly divided into diabetic group (DM group, 17 rats) and tBHQ group (18 rats). The rats in tBHQ group were fed with high fat and sugar diet with 1% tBHQ. After 4 weeks and 12 weeks of tBHQ intervention, hematoxylin eosin staining of retinal sections, immunohistochemical staining and quantitative polymerase chain reaction (PCR) of Nrf2 and HO-1 were performed. ResultsIn tBHQ control, the retina of rats was normal and individual cells showed slightly edema at 4 weeks; the retinal structure of rats was clear and part of cells showed edema at 12 weeks. At 4 and 12 weeks, the expression of Nrf2 (t=3.115, 3.781) and HO-1 (t=3.485, 3.785) protein in DM group were higher than that in NC group (P < 0.05); the expression of Nrf2 (t=2.473, 2.576) and HO-1 (t=2.785, 2.879) protein in tBHQ group were higher than that in DM group (P < 0.05). In DM group, the expression of Nrf2 protein at 12 weeks was higher than that at 4 weeks (t=0.276, P < 0.05). In tBHQ group, the expression of Nrf2 (t=2.516) and HO-1 (t=2.776) protein at 12 weeks were higher than that at 4 weeks (P < 0.05). 4 and 12 weeks, the expression of Nrf2 (t=4.758, 4.285) and HO-1 (t=5.114, 4.514) mRNA in DM group were higher than that in NC group (P < 0.05); the expression of Nrf2 (t=5.133, 4.976) and HO-1 (t=4.758, 4.251) mRNA in tBHQ group were higher than that in DM group (P < 0.05). In DM gruop, the expression of Nrf2 protein at 12 weeks was higher than that at 4 weeks (t=5.114, P < 0.05). In tBHQ group, the expression of Nrf2 (t=4.292) and HO-1 (t=4.974) protein at 12 weeks were higher than that at 4 weeks (P < 0.05). ConclusiontBHQ intervention can increased the expression of Nrf2, HO-1 significantly in the retina of type 2 diabetic rats.
ObjectiveTo explore the effect and mechanism of netrin-1 on blood-retinal barrier permeability in diabetes mellitus (DM) rats. MethodsEighty Sprague-Dawley rats were randomly divided into the normal control group, DM+balanced salt solution (BSS) group, DM+netrin-1 low dose group and DM+netrin-1 high dose group, with 20 rats in each group. DM rats were induced by intraperitoneal injection of streptozocin (STZ). These rats were feed with high sugar and fat for 3 months after STZ injection. All rats were sacrificed at 1 month after intravitreal injection. Retinal vascular permeability was measured by Evans blue. The expression level of occludin was determined by immunohistochemistry. Hematoxylin-eosin (HE) staining of retina was used to observe the pathological change of DM and the level of occludin mRNA was analyzed by real-time fluorescence quantitative reverse transcription polymerase chain reaction (RT-PCR). Five rats of each group. ResultsHE staining of retina showed that the degree of edema and vascularization in DM+netrin-1 high dose group was better than DM+BSS group. Staining of occludin in retina was limited to nerve fiber layer, ganglion cells, inner plexiform layer and inner nuclear layer in normal rats, but in DM+BSS group, the color of staining positive of occludin was lighter and more reduced. However, DM+ netrin-1 group occludin staining was deepen and enlarged. The result of RT-PCR showed that the expression of occludin mRNA in other three groups was less than normal control group (P < 0.05). The significant difference during DM+BSS group, low dose group and DM+netrin-1 high dose group (F=177.13, P=0.00), and the more concentrate of netrin-1 the higher expression of occluding. Compared the DM+netrin-1 low dose group with DM+BSS group, there was significant difference expression of occludin (t=-13.98, P=0.00). There was significant difference between the DM+netrin-1 high dose group and normal control group (t=12.87, P=0.00). There was statistically significant difference in DM+BSS group, DM+netrin-1 low dose group and DM+netrin-1 high dose group (F=179.69, P=0.00). Compared the two group of different concentration netrin-1, the quantification of vascular permeability in DM+netrin-1 high dose group reduced more (t=12.73, P=0.00). ConclusionsNetrin-1 can protect the blood-retinal barrier in DM rats. Netrin-1 may decrease BRB leakage in DM rats by protecting the expression of occludin.
Objective To observe the effect of netrin-1 on retinal Müller cells in diabetes mellitus (DM) rats. Methods Fifty Sprague-Dawley rats were randomly divided into the normal control group (group A), normal + balanced salt solution (BSS) group (group B), normal+netrin-1 group (group C), DM+BSS group (group D) and DM+netrin-1 group (group E), with 10 rats in each group. DM rats were induced by intraperitoneal injection of Streptozotocin (60 mg/kg). The expression level of glial fibrillary acidic protein (GFAP) on retinal Müller cells was determined by immunohistochemistry, the level of GFAP mRNA was analyzed by real-time fluorescence quantitative reverse transcription polymerase chain reaction. Results Immunohistochemistry showed that GFAP was distributed in retinal ganglion cells and retinal nerve fiber layer in group A, B and C. Compared to group B, GFAP staining was brighter in the group D. There were significant differences in the expression of GFAP protein and mRNA among groups A-E (F=203.43, 72.91; P=0.00, 0.00), they were higher in group D than group A (t=?26.01, 22.26; P=0.00, 0.00), and group E (t=?10.78, 3.93; P=0.00, 0.00). They were higher in group E than group A (t=7.00, ?9.82; P=0.00, 0.00). There were no significant differences in between group A and group C (t=?0.29, 0.50; P=0.77, 0.62). Conclusion The expression of GFAP in Müller cells of DM rats could be decreased by injecting netrin-1 into vitreous.
ObjectiveTo predict as well as bioinformatically analyze the target genes of has-miR-451. MethodsmiRBase, miRanda, TargetScan and PicTar were used to predict the target genes of hsa-miRNA-451. The functions of the target genes were demonstrated by Gene Ontology and pathway enrichment analysis. P < 0.05 was set as statistically significant. Results18 target spots of hsa-miRNA-451 were predicted by 3 databases or prediction software at least. The functions of the target genes were enriched in proliferation and development of epithelial cells and regulation of kinase activity (P < 0.05). Pathway analysis showed that transforming growth factor-beta signaling pathway, mitogen-activated protein kinase signaling pathway, epidermal growth factor signaling pathway, Wnt signaling pathway and mammalian target of rapamycin signaling pathway were significantly enriched (P < 0.05). Conclusionhsa-miRNA-451 might be involved in various signaling pathways related to proliferation and development of epithelial cells.