The Study Of The Relevance Between Trend Variability Of AMPK/mTOR In Hippocampus Of Rats And Neurological Function Scores After Permanently Bilateral Common Carotid Artery Ligation

Objective：To establish the model of2-VO in rats with cerebral ischemia,investigate the the relevance between trend variability of AMP-activated poteinkinase（AMPK）and mammalian target of rapamycin（mTOR）in hippocampus ofrats and neurological function score in acute ischemic brain injury.Methods： Twenty-four female Sprague-Dawley(SD) rats were randomlydiveded into sham operation group(group A),ischemia4h group(group B),ischemia8h group(group C) and ischemia24h(group D). There were6rats in each group. Thebrain acute ischemia model was established by reference and modify method of2-VO in rats. A group only received operation reveal bilateral common carotid arteryand dissociate the Vagosympathetic chain, without ligation and transection ofbilateral artery. Suture of incision and accroding to the modified method of nervedeficit score (NDS) from consciousness, basic reflection, feeling, movement,behavior score when awake.Guillotined and take the bilateral hippocampus; B、C、D groups were operated after anesthesia, exposed bilateral common carotid arteries,dissociated bilateral vagosympathetic nerve chain, ligated bilateral common carotidartery proximal end and centrifugal end, cut the ligation segment midpoint of carotidartery,respectively, at4h after the operation (group B),8h (group C),24h (group D)were killed by decapitation and took hippocampus bilaterally.B、C、D groups weremeasured by improved NDS a quarter before killed. Use left hippocampus todetermined the expression of the AMPK、mTOR、p-AMPK、p-mTOR、p-4E-BP1和p-S6K1by Western Blot. To observe the cell morphological change by HEstaining of the right hippocampus of every rat model.Results：(1)The change of NDS: the NDS score of ischemia for4hours (groupB) and8hours (group C) were decreased compared with sham operationgroup(group A),and the NDS scores will increase with ischemia time.The differencewas statistically significant (P <0.01). The highest NDS score is ischemia for24hours (group D), the difference has no statistical significance (P>0.05) with group A.(2)Determined the change of AMPK and mTOR activity in hippocampus: Theactivity of AMPK was increased in the brain tissue when ischemia, the activationdegree reached the maximum at4h, there was significant (p<0.01), then8hdecreased gradually (p<0.01),24h touched bottom.No statistically significantbetween group A and group D. However the activity of m-TOR was significantlydecreased in the brain tissue when ischemia,4h was the maximum degree ofinhibition,then increased gradually at8h and24h.24h appeared to be most activebut remained below A group. The difference was statistically significant (p <0.01);(3) The expression change of p-S6K1and p-4E-BP1in hippocampus: Theexpression of p-S6K1was significant decreased when ischemia. The expressionreached the lowest at4h（p<0.01）. As the extension of ischemia time, the expressionincreased.24h reached the top. The difference has no statistical significancewithgroup A (p>0.05). The expression of p-4E-BP1of each time point after cerebralischemia decreased significantly compared with sham operation group (p＜0.01).The expression will increase with the passing of time.The difference was statisticallysignificant (p <0.01).Through a scatter diagram parallel correlation analysis showed: In hippocampus,significant negative correlations were found between the expression of AMPK andmTOR（r=-0.948, p<0.01）. The expression of AMPK was negatively related to NDS（r=-0.826, p<0.01）. There was positive correlation between the expression ofmTOR and NDS（r=0.864,p<0.01）.Conclusion：AMPK/mTOR signal path was actived in hippocampus in ratsafter celebral ischemia.Their expression is antagonistic at each time point throughchange p-S6K1and p-4E-BP1activity on downstream to control of protein synthesis.Activation of AMPK makes against restoration of nervous system. Changedevelopment of cerebral ischemic injury from affecting the expression of AMPK andMtor signal path can be used as a new target for the treatment of acute cerebralischemic injury.