Expression of miR-126 in brain ischemic injury tissues of diabetic rats and its significance in angiogenesis

Abstract

Objective To investigate the expression of micro RNA (miR)-126 in brain ischemic injury tissues of diabetic rats and its significance in angiogenesis. Methods Fifty adult female rats were randomly divided into five groups according to random number table: diabetic group, cerebral ischemia group, diabetic+cerebral ischemia group, miR-negative+diabetic+cerebral ischemia group and miR-126 mimics+diabetic+cerebral ischemia group (n=10). The models of diabetic and (or) focal cerebral ischemia were esblished, respectively. The rats in the later two groups were injected with 10 μg miR-negative control or 10 μg miR-126 mimics through ateral ventricle. Twenty-four h after cerebral ischemia modeling, the neurological functions of rats were assessed by using Zea-Longa scoring criteria, and infarct areas in the brain slices were analyzed by TTC staining. The expressions of miR-126, platelet-endothelial cell adhesion molecule-1 (PECAM-1), vascular endothelial cadherin (VE-cad) and vascular endothelial growth factor (VEGF) in the ischemic cortex tissues were detected by real time-PCR. Results The neurological scale scores and cerebral infarct volumes of rats in miR-negative+diabetic+cerebral ischemia group and diabetic+cerebral ischemia group were significantly higher than those in the diabetic group and cerebral ischemia group (P<0.05); and those in the miR-126 mimics+diabetic+cerebral ischemia group were significantly lower than those in the miR-negative+diabetic+cerebral ischemia group, diabetic cerebral ischemia group and cerebral ischemia group (P<0.05). The relative mRNA expression levels of miR-126, PECAM-1, VE-cad and VEGF in the ischemic cortex tissues of cerebral ischemia group, diabetic+cerebral ischemia group, miR-negative+diabetic+cerebral ischemia group were significantly lower than those in the diabetic group (P<0.05); those in the diabetic+cerebral ischemia group and miR-negative+diabetic+cerebral ischemia group were significantly lower than those in the cerebral ischemia group (P<0.05); those in the miR-126 mimics+diabetic cerebral ischemia group were statistically higher than those in the diabetic group, cerebral ischemia group, diabetic cerebral ischemia group and miR-negative+diabetes cerebral ischemia group (P<0.05). Conclusion Up-regulation of miR-126 could help relieve diabetic ischemic brain tissue injury and improve neurological function, which might be related to the regulation of angiogenesis after cerebral ischemic injury. Key words: Micro RNA-126; Diabetes mellitus; Cerebral ischemic injury; Angiogenesis