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)
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.
ObjectiveTo observe the expression of glutamate (Glu) andγ-aminobutyric acid (GABA) in the retina of diabetic rats which were intervened later by insulin intensive therapy, and to investigate the mechanism of metabolic memory of hyperglycemia which induced the retina neuropathy in diabetic rats. Methods60 Brown Norway rats were randomly divided into normal control (NC) group, diabetes mellitus (DM) group (6 weeks at DM1, 12 weeks at DM2) and metabolic memory (MM) group, 15 rats in each group. Diabetes was induced by intraperitoneal injection of streptozocin. After 6 weeks, MM group was treated with insulin intensive therapy for 6 weeks. DM1 group was sacrificed at the end of 6 weeks and other groups were sacrificed at the end of 12 weeks. High performance liquid chromatography was used to detect the amount of Glu and GABA in the rat retina. Real-time polymerase chain reaction was applied to quantify the mRNA expressions of Glutamate decarboxylase (GAD). TdT mediated dUTP nick ending labelling was used to detect cell apoptosis. ResultsThe concentration of Glu (t=6.963), GABA (t=4.385) and the ratio of Glu/GABA (t=4.163) in MM group were significantly higher than DM1 group, but the concentration of Glu (t=3.411) and GABA (t=3.709) were significantly lower than DM2 group (P < 0.05). And there was no significant difference in the ratio of Glu/GABA between MM and DM2 groups (t=1.199, P > 0.05). The level of expressions of GAD mRNA in MM group was significantly lower than DM1 group (t=3.496, P < 0.05), but higher than DM2 group (t=8.613, P < 0.05). The number of nerve cells apoptosis in MM group was significantly higher than DM1 group (t=2.584, P < 0.05), but lower than DM2 group (t=3.531, P < 0.05). ConclusionsIntensive therapy later by insulin can partially reduce the content of Glu and GABA and the rate of nerve cells apoptosis, which cannot return to normal levels, and has no effect on the rise in the ratio of Glu/GABA caused by the hyperglycemia. The disorders of Glu and GABA may participate in the metabolic memory of hyperglycemia.
ObjectiveTo observe the expression of Toll-like receptor 4 (TLR4) and inflammatory cytokines, leucocytic density and permeability in retina of diabetic rat. MethodsA total of 106 Brown Norway rats were randomly divided into experimental group and control group with 53 rats in each group. Diabetic model was established in experimental group by intraperitoneal injection of streptozotocin, and control rats received intraperitoneal injection of an equal volume of citric acid-sodium citrate buffer. Four weeks later, the retinas were collected for further analysis. TLR4 RNA and protein expression were measured by quantitative polymerase chain reaction and Western blot. Inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), monocyte chemo-attractant protein-1 (MCP-1), were measured by enzyme-linked immunosorbent assay in rat retina homogenate. Leukocyte density in the retina was measured by acridine orange fundus angiography. The retinal permeability was evaluated by Evans blue (EB) staining. ResultsTLR4 expression was significantly increased in diabetic rats of experimental group compared with non-diabetic rats of control group (F=1.606, 0.789; P < 0.05). Inflammatory cytokines (TNF-α, IL-1β and MCP-1) were significantly increased in retina of diabetic rats of experimental group versus non-diabetic rat of control group (F=24.622, 5.758, 4.829; P < 0.05). The retinal leukocyte density was (6.2±0.5)×10-5, (2.2±0.3)×10-5 cells/pixel2 in experimental and control group respectively, the difference was statistically significant (F=2.025, P < 0.05). The amount of retinal EB leakage was (23.41±4.47), (13.22±3.59) ng/mg in experimental and control group respectively, the difference was statistically significant (F=21.08, P < 0.05). ConclusionTLR4 and inflammatory cytokines expression, leucocytic density and permeability increased significantly in retina of diabetic rat.