The Study Of Ampelopsin （AMP） Ameliorating Cerebral Ischemia Injury In Mice By Regulating Glutamine Metabolism

(1)Objective:To investigate the therapeutic effect of ampelopsin（AMP）on cerebral ischemia in mice,and to explore whether the mechanism is related to astrocyte and neuronmediated glutamate-glutamine cycle.（2）Methods:The experiment was divided into sham operation group,model group,CB-839（200 mg/kg）control group and AMP（300 mg/kg）group.Right cerebral ischemia（MCAO）model was established in the model group,with ischemia blocking for 30 min and reperfusion for 24 h.The sham group performed the same procedure but did not insert a thread plug.AMP（300 mg/kg）group was given intragastric administration 30 min before modeling,and CB-839（200 mg/kg）group was given intragastric administration 6 and 2 h before modeling,respectively.24 h after reperfusion,weight difference,area of cerebral infarction,neurological symptoms and brain water content of each group were measured to evaluate the therapeutic effect of AMP and CB-839 on cerebral ischemia in mice.HE staining and Nissl staining were used to observe the pathological changes and damage of nerve tissue,neurons and Nissl bodies in the brain of the affected side of mice.Meanwhile,the activities of glutaminase（GLS）and glutamine synthase（GS）,the contents of glutamate（Glu）and glutamine（Gln）,and the protein expression levels of GLS,GS,GLT-1 and NMDAR in the brain of the affected side of mice were detected.The expressions of GS,GFAP,GLS and Neu N in astrocytes and neurons were observed by fluorescence double staining,to determine the effect of AMP on glutamate-glutamine metabolism between astrocytes and neurons.（3）Results:AMP（300 mg/kg）and CB-839（200 mg/kg）significantly improved the neurological injury symptoms,reduced the area of cerebral infarction,and alleviated cerebral edema in cerebral ischemia mice.The results of HE staining and Nissl staining showed that the cerebral nerve tissue and cells in the affected side of MCAO mice in the model group were accompanied by extensive damage and necrosis.Besides,neurons and Nissl bodies were collapsed and necrotic in large quantities.AMP（300mg/kg）and CB-839（200 mg/kg）reduced the injury and necrosis of nerve tissue,rescued the damage of neurons and Nissl bodies in the affected side of ischemic mice,played a role in protecting nerve tissue and neurons.The mechanism of the therapeutic and neuroprotective effects of AMP（300 mg/kg）and CB-839（200 mg/kg）on cerebral ischemia mice is related to the regulation of Glu-Gln circulation metabolism.AMP（300mg/kg）and CB-839（200 mg/kg）inhibited the hydrolysis of Gln to Glu by inhibiting the content and expression of GLS,and accelerated the conversion of Glu to Gln by enhancing the activity and expression of GS.Through the dual effects of Glu synthesis and metabolism,the content of Glu decreased and the content of Gln increased in the affected brain of cerebral ischemia mice.Meanwhile,AMP（300 mg/kg）and CB-839（200 mg/kg）accelerated Glu uptake and reabsorption by increasing the expression of GLT-1 in the brain of ischemic mice,and prevented the excessive accumulation of Glu in the brain of ischemic mice.AMP（300 mg/kg）and CB-839（200mg/kg）alleviated the over-binding of Glu to NMDAR by decreasing the expression of NMDAR.Thus,the excitatory toxicity induced by Glu was alleviated,and the nerve injury of cerebral ischemia mice was improved.（4）Conclusion:AMP ameliorated nerve injury in cerebral ischemia-reperfusion（MCAO）mice by regulating the glutamate-glutamine cycle between astrocytes and neurons,and had therapeutic effects on focal cerebral ischemia in mice.