Abstract: Objective: To investigate the expression of microRNA-155(miRNA-155) in the cerebral cortex tissue of the rats with cerebral ischemia-reperfusion injury, and to clarify the effect of miRNA-155 on cerebral ischemia-reperfusion injury.Methods: A total of 48 healthy adult male SD rats were randomly divided into sham operation group(n=24) and cerebral ischemia reperfusion group(I/R group,n=24).The cerebral ischemia-reperfusion models in I/R group were established by Longa modified suture occlusion in the right middle cerebral artery of the rats.The rats in sham operation group only received blood vessel isolation.TTC staining was used to calculate the ischemic infarction volume of the rats in various groups.qRT-PCR method was used to detect the expression levels of miR-155 in cerebral cortex tissue of the rats in various groups.Results: Compared with sham operation group, the ischemic infarction volume of the rats in I/R group was significantly increased at 24,48,and 72 h after reperfusion(P<0.05);the ischemic infarction volumes of the rats in I/R group were decreased gradually with the prolongation of reperfusion time.Compared with sham operation group,the expression levels of miR-155 in cerebral cortex tissue of the rats in I/R group were significantly increased at 24, 48, and 72 h after reperfusion (P<0.05); the expression levels of miR-155 were gradually decreased with the prolongation of reperfusion time.Conclusion: The expression levels of miR-155 in cerebral cortex tissue of the rats with cerebral ischemia-reperfusion injury are high, and miR-155 may participate in the process of cerebral ischemia-reperfusion injury.

Key words: microRNA-155, cerebral ischemia, reperfusion injury, rats,SD