Dexmedetomidine Improves Cerebral Ischemia-Reperfusion Injury in Rats via Extracellular Signal-Regulated Kinase/Cyclic Adenosine Monophosphate Response Element Binding Protein Signaling Pathway

OBJECTIVE: To investigate the mechanism of dexmede- which may provide new ways for clinical treatment of tomidine (Dex) in improving brain damage induced by cerebral ischemia-reperfusion injury. cerebral ischemia-reperfusion injury in rats. METHODS: Rats were randomly divided into a sham operation group, ischemia-reperfusion group, Dex group, piracetam group, and yohimbine + Dex group, with 12 rats per group. 2,3,5-Triphenyltetrazolium chloride staining was used to analyze cerebral infarct size. Hematoxylin-eosin staining and immunohistochemistry were used to observe brain damage caused by ischemia-reperfusion. Cognitive and memory functions was detected by Morris water maze test, and the expression of phosphorylated extracellular signal-regulated kinases 1 and 2 (ERK1/2) and phosphorylated cyclic adenosine monophosphate response element binding protein (CREB) were measured by Western blot. RESULTS: Cognitive dysfunction was improved in the Dex group and the piracetam group compared with the ischemia-reperfusion group. Compared with the ischemiareperfusion group, infarct size and neuronal cell death rates were decreased in the Dex group and the piracetam group. The expression of phosphorylated ERK1/2 and phosphorylated CREB in the Dex group was increased, whereas the expression of phosphorylated ERK1/2 and phosphorylated CREB in the yohimbine + Dex group was lower than in the Dex group (P < 0.05). CONCLUSIONS: Dex improved ischemic brain damage by promoting signal transduction of the ERK/CREB pathway, which may provide new ways for clinical treatment of cerebral ischemia-reperfusion injury.