Protective Effects Of Β-caryophyllene On Cerebral Ischemia-reperfusion Injury And PI3K/Akt Signaling Pathway

Objective:This study aimed to To investigate the effects of β-caryollene（BCP）pretreatment on focal cerebral ischemia-reperfusion injury and the underlying mechanism.Methods:（1）40 Adult male Sprague–Dawley rats were randomly divided into 4 groups: the sham-operated group（Sham）,vehicle group（vehicle）,β-Caryophyllene 102 mg·kg^-1 group（L）,β-Caryophyllene 306 mg·kg^-1 group（H）.Middle Cerebral Artery Occulusion（MCAO）was used to establish the cerebral ischemia-reperfusion injury model by intravascular nylon filament occlusion.The focal cerebral ischemia-reperfusion injury was induced by 90 mins of ischemia followed by 24 h reperfusion.The neurologic deficit score and the infarct volume was measured after 24 h of reperfusion.The ratio of apoptotic cells was determined by flow cytometry（FCM）.（2）90 Adult male Sprague–Dawley rats were ramdomly divided into 6 groups: sham-operated group（sham）,vehicle group（vehicle）,β-Caryophyllene 102 mg·kg^-1 group（L）,β-Caryophyllene 306 mg·kg^-1 group（H）,β-Caryophyllene 306 mg·kg^-1 + wortmannin group（H+W）and wortmannin group（W）.RT-qPCR and western blot were used to assess the mRNA and protein expressions of bcl-2,bax,p-53 and the p-Akt in cortex and hippocampus.The neurologic deficit score and the infarct volume were determined 24 h after reperfusion.And the p-Akt levels were determined by western blot.Results:（1）When compared with sham group,BCP pretreatment can significantly reduced the neurologic deficit score and the infarct volume（P <0.05）,and considerably lowered the ratio of apoptotic cells in hippocampus.Moreover,BCP pretreatment also positively regulated the expression of bcl-2 and the level of p-Akt,and negatively regulated the expressions of bax and p-53 in rats brains.（2）When compare with H group,intravenously injection of wortmannin,the specific PI3 K inhibitor,reversed the BCP pretreatment-induced positive effects on neurologic deficit score and infarct volume.And administration of wortmannin totally abolished the BCP-induced enhancement in level of p-Akt.Conclusion:All our results indicated that BCP pretreatment is critical in neuroprotective effect against focal cerebral ischemia-reper fusion injury by alleviating apoptosis,and the anti-apoptotic effect is associated with activation of PI3K/Akt signaling pathway.