ABSTRACT
Objective To investigate the effect of up-regulation of miR-132 on expressions of angiopoietin-1 (Ang-1)/endothelium-specific tyrosine kinase receptor 2 (Tie2) in focal cerebral ischemia reperfusion injury of rats.Methods Forty adult healthy SD rats were randomly divided into sham-operated group,cerebral ischemia group,miR-132 mimic group and negative control group (n=10).The models of middle cerebral artery occlusion in the later three groups were established by using modified Longa suture method.Rats in the miR-132 mimic group and negative control group were injected miR-132 mimic 15 μg and negative control 15 μg via paracele.Rats in each group were sacrificed 24 h after ischemia,and the brain tissues were collected;the total infarct volumes were calculated by TTC staining.The mRNA expressions ofmiR-132,Ang-1 and Tie2 in ischemic cerebral cortex tissues were detected by real-time fluorescence quantitative PCR.The protein expressions of Ang-1,Tie2,CD31 and vessel endothelial growth factor (VEGF) in ischemic cerebral cortex tissues were detected by Western blotting.Results The total infarct volume in the miR-132 mimic group was (27.92±3.05) mm3,which was significantly smaller than that in the cerebral ischemia group and negative control group ([51.34±2.86] mm3 and [50.46±2.57] mm3,P＜0.05).The relative mRNA expression levels of miR-132,A ng-1,Tie2,and the protein expression levels of Ang-1,Tie2,CD31,VEGF in the ischemic cerebral cortex tissues of the miR-132 mimic group were significantly higher than those in the negative control group,cerebral ischemia group and sham-operated group (P＜0.05);and those in the negative control group and cerebral ischemia group were significantly higher than those in the sham-operated group (P＜0.05).Conclusion Up-regulation ofmiR-132 expression could improve the ischemic states of ischemic stroke in rats,which might be related to Ang-1/Tie2 increased expressions to promote angiogenesis in ischemic brain tissues.