Dexmedetomidine pretreatment alleviates brain injury in middle cerebral artery occlusion (MCAO) model rats by activating PI3K/AKT/NF-κB signaling pathway

Cerebral ischemia-reperfusion injury (CIRI) is a prevalent clinical complication associated with reperfusion following ischemic stroke resulting in neuronal damage and cognitive impairment. Dexmedetomidine (DEX), a highly selective alpha 2-adrenoceptor agonist with sedative, and analgesic properties, is frequently utilized as a sedative anesthetic in clinical surgeries, and believed to play a crucial role in the prognosis of patients suffering from CIRI. However, the mechanism underlying DEX in CIRI remains to be determined. This study aimed to investigate the neuroprotective effects of Dex in rats suffering from CIRI. In the treatment group, DEX (50 mu g/kg) was administered intraperitoneally 30 min prior to surgery. Middle cerebral artery occlusion (MCAO) used as a model of CIRI occurred with cerebral artery occlusion for 2 h was followed by reperfusion with blood for 24, 72, 120 or 168 h. Neurological function as assessed by the Longa neurological function score test demonstrated significantly reduced neurological scores and increased % infarct size in MCAO group which was blocked by DEX suggesting that DEX might be effective in treating ischemic stroke. In the MCAO animals, 2,3,5-triphenyltetrazolium chloride (TTC) showed large marked areas of cerebral infarction which were diminished in size by DEX. Using Western blot analysis, results showed that in MCAO rats protein expression levels of TNF-alpha and IL-6 were increased accompanied by reduced protein expression levels of PI3K/AKT signaling pathway. DEX pretreatment reversed the effects of MCAO as evidenced by decrease in protein expression levels of TNF-alpha and IL-6 associated with elevated protein expression levels of PI3K/AKT/NF-kappa B signaling pathway. Data demonstrated that DEX pretreatment improved the neuromotor performance and cognitive functions in animals suffering from consequences of MCAO by diminishing inflammation and activation of the PI3K/AKT/NF-kappa B signaling pathway.