Cerebral Ischemic Prconditioning Attenuates Cerebral Ischemia/Reperfusion Injury Via Activating The SIRT1-FoxO1 Signaling Pathway

With the development of aging population,stroke has become one of the main causes of morbidity and mortality among the middle-aged and elderly people in the world,and it is increasing year by year.Its high disability rate and high recurrence rate not only reduce the quality of life of patients,but also bring heavy burden to the society and family.Currently,the approved and effective therapies for acute ischemic stroke includes the intravenous tissue fibrinolytic enzyme activator(t PA)within 4.5 hours and venous thrombectomy within 24 hours,but they still induced ischemia/reperfusion(ischemia-reperfusion,I/R)injury inevitably,and the narrow therapeutic window and potential side effects limit its clinical application.A large number of studies have shown that cerebral ischemic preconditioning(cerebral ischemicpreconditioning,CIP)can reduce cerebral ischemia reperfusion injury,and silent information regulator 1(SIRT1)is a kind of histones to formyl enzyme,its activity depends mainly on nicotinamide adenine dinucleotide(NAD~+),it play an important role in the prevention of ischemic stroke.At present it is widely studied resveratrol,as a kind of SIRT1 specificity activator,its downstream substrate can be applied by the deacelation into to fork box O1(forkhead box O1,FoxO1),playing a role on oxidative stress,autophagy and apoptosis and anti-inflammatory and so on.To explore wether the SIRT1-FoxO1 signaling pathway plays a role in the protection of cerebral ischemia-reperfusion injury by cerebral ischemia preconditioning or not,This study,using the establishment of right middle cerebral artery occlusion(MCAO)model,studied the oxidative stress and autophagy.There were 126 male Sprague Dawley(SD)rats,weighed only 250-280 g,randomly divided into 3 groups:control group(the control,n=42),cerebral ischemia reperfusion group(I/R,n=42)and ischemic preconditioning group(CIP,n=42),Koizumi preparation of middle cerebral artery embolism model was adopted in the I/R group which were gived ischemia reperfusion after 2 h.CIP group used the method of secondary line switch,which were gived ischemia as the pretreatment for10 min,then reoperation after 3 d,ischemia reperfusion after 2 h.The control group were separated blood vessels,without ischemia processing.Six rats in each group were randomly selected for2,3,5-triphenyltetrazolium chloride(TTC)staining on 1d later for cerebral infarction volume measurement,and the rest were randomly divided into three subgroups at 6h,12h and 24h.Neurological function score was performed at each time point using Zealonga scoring standard,and 24h time point was selected for analysis.Using the real-time quantitative polymerase chain reaction lock(Real-time Quantitative Polymerase Chain Reaction,RT-q PCR)determinated the expression level of SIRT1m RNA,FoxO1 m RNA.Protein imprinting method(Western blot)determinated expression level of SIRT1,Fox O,LC3-II/I,Beclin1protein.SOD activity in brain tissue homogenate was measured by water-solubletetrazolium-1(WST-1)method.Thiobarbituric acid(TBA)method was used to determine the content of MDA in the homogenate of brain tissue.CIP significantly improved neurobehavioral deficit and neurological impairment score in I/R rats,and decreased cerebral infarct volume.Compared with the control group,the I/R group raised SIRT1m RNA,FoxO1 m RNA,SIRT1,FoxO1,LC3-II/I,Beclin1 expression since 12 h after ischemia reperfusion.Compared with the I/R group,CIP group raised same indicators since 6 h significantly;In I/R group,SOD decreased significantly,MDA increased significantly.CIP significantly up-regulated SOD and down-regulated MDA.In conclusion,cerebral ischemia preconditioning can alleviated cerebral ischemia reperfusion injury via activating SIRT1-FoxO1signaling pathway to activate autophagy and antioxidant stress.