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Objective To investigate the effect of expressions of endothelial growth factor (VEGF) and VEGF receptor 2 (VEGFR2) in the ischemic cortex on ischemic cerebral injury in rats with diabetes mellitus.Methods A total of 36 healthy male Sprague-Dawley rats were divided into 3 groups:a shamoperation group,a cerebral ischemic group,and a diabetic cerebral ischemic group according to the random number table method.A diabetes model was induced by injection of streptozocin,and then,a permanent focal cerebral ischemic model was induced by the suture method.At 24 h after ischemia,the neurological deficit scores were conducted.The triphenyl tetrazolium chloride staining was used to measure the infarct volume.TUNEL was used to detect the apoptotic cells.Real-time fluorescence quantitative polymerase chain reaction was used to detect the expression levels of VEGF and VEGFR2 mRNAs.Western blot was used to detect the expression levels of VEGF and VEGFR2 proteins.Results In the sham operation group,there were no neurological deficit and infarcts,and there were only a few apoptotic cells and a few expressions of VEGF,VEGFR2 mRNAs and protein.The neurological function score (4.25 ±0.54 vs.2.86 ±0.73);t =5.303,P＜0.001),infarct volume (51.69 ±2.26 mm3 vs.30.15 ±2.08 mm3;t =23.166,P＜0.001),and the number of apoptotic cells (24.22 ± 1.34/HP vs.13.28 ±0.37/HP;t =27.261,P＜0.001) in the diabetic cerebral ischernia group were significantly increased than those in the cerebral ischemic group,while VEGF,VEGFR2 mRNA,and protein expression level were significantly decerased (VEGF mRNA:4.74 ± 0.54 vs.6.71 ± 0.91,P ＜ 0.001;VEGFR2 mRNA:4.06 ± 0.60 vs.6.16 ± 0.96,P ＜ 0.001,VEGF protein:0.99 ± 0.13 vs.1.55 ± 0.23,P ＜ 0.001;VEGFR2 protein:4.12 ± 0.74 vs.6.23 ± 0.76,P ＜ 0.001) compare with the cerebral ischemic group.Conclusions VEGF/VEGFR2 signal pathway participates in diabetes aggravating ischemic cerebral injury.The downregulating of VEGF/VEGFR2 may be one of the mechanisms of diabetes aggravating ischemic cerebral injury.
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AIM:To evaluate the effect of microRNA-155(miRNA-155) on the regulation of angiogenesis in diabetic rats with cerebral ischemic injury .METHODS: Adult male Sprague-Dawley rats were randomly divided into 5 groups:sham group, cerebral ischemia group , diabetic cerebral ischemia group , diabetic cerebral ischemia +miRNA-155 inhibitors group and diabetic cerebral ischemia +scramble group .Diabetes model was made by injection of streptozocin and permanent cerebral ischemic model was developed by suture-occluded method .The scores of neurological deficit and infarct volume were estimated at 24 h after cerebral ischemia .miRNA-155 level was detected by real-time polymerase chain reaction.The expression of platelet endothelial cell adhesion molecule-1 ( PECAM-1/CD31 ) and vascular endothelial growth factor ( VEGF) was detected by Western blotting .RESULTS:miRNA-155 inhibitor significantly reduced miRNA-155 levels in the ischemic cortex (P<0.05), improved the scores of neurological deficit , reduced infarction size and up-regulated the levels of CD31 and VEGF (P<0.05).CONCLUSION:miRNA-155 has a critical role in the regulation of angiogenesis in diabetic rats with cerebral ischemia .Down-regulation of miRNA-155 using miRNA-155 inhibitor attenuates brain infarct injury in diabetic rats .
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microRNAs (miRNAs) are a class of small non-coding RNAs (length 21 to 25 nt).They can complement and bind to 3' non-coding region of their target genes,directly degrade target genes or inhibit the translation of encoding proteins,and extensively participate in development,metabolism,apoptosis,and a variety of disease processes.Studies have shown that miRNAs play important roles in the occurrence and development of ischemic stroke,and participate in post-stroke protection and regulation of repair mechanisms.