The Effect Ofβ-ARB For Bax、Bcl-2 And NGF Expression Of Cerebral Ischemia-reperfusion Injury In Rats

Objective: To observe the effect of MTT-treatment and Propranolol-treatment on the histologicoutcome，apoptosis at different time points on the model of focal cerebral ischemia-reperfusioninjury in rats，To investigate the expression of Bax、Bcl-2 and NGF in the model of focalcerebral ischemia-reperfusion and the neuroprotective effect of MTT-treatment andPropranolol-treatment，To explore the neuroprotective mechanism ofβ-adrenergic receptorblockers in the model of focal cerebral ischemia-reperfusionModels:Seventy-two male adult wistar rats were divided into sham operation group、ischemia-reperfusion group、Propranolol-treatment and MTT-treatment grouprandomly,reperfusion 12h、24h、48h three sub-groups were divided in each group according totheir reperfused time point.The model of Focal cerebral ischemia-reperfusion injury was madeby line embolism method.HE staining of pathological changes in brain tissuemorphology;neuronal apoptosis was detected by TUNEL,to observe Bax、Bcl-2 and NGFexpression was by immunohistochemisery.Resules: 1.HE staining shows that infarction and neuronal injury was relieved at different timepoints in the MTT-treatment group and Propranolol-treatment compared with I-Rgroup .2.Expresion of Bax and NGF positive cells was found after cerebral ischemia followedby reperfusion 12h in the penumbra zone,it reached a peak level at 24h afterreperfusion(P<0.05), then declined,expression of Bcl-2 positive cells reached a peak level aftercerebral ischemia followed by reperfusion 12h in the penumbra zone，thendeclined(P<0.05).Expression of Bax in MTT-treatment group and Propranolol-treatment groupat all time points were distinctly lower than ischemia-reperfusion group(P<0.05),but upper thansham group(P<0.05).Expression of Bcl-2 in MTT-treatment group and Propranolol-treatmentgroup at all time point were distinctly upper than ischemia-reperfusion group. Expression ofNGF positive cells was found in MTT-treatment group and ischemia-reperfusion group almostthe same. Expresion of Bax in Propranolol-treatment group at all time points were distinctlylower than ischemia-reperfusion group(P<0.05).3.Ischemia-reperfusion group of thecontralateral cerebral hemisphere and sham operation group occasional apoptoticcells ,speculate that is physiological neuronal necrosis.A large number of TUNEL-positive cellswere observed in I-R group (P<0.05),TUNEL-positive cells were obvious reduced in theMTT-treatment group and Propranolol-treatment group ,but higher than the sham group(P<0.05 ).Conclusion: 1.Focal cerebral ischemia and reperfusion model were success fully replicated.therats development typical symptoms of neurological impairment.HE staining results in line withpathological process.2.MTT-treatmentand Propranolol-treatment could attenuate cell death aftercerebral ischemia-reperfusion show neuroprotective effect.3.MTT-treatmentand Propranolol-treatment obviously inhibited transient focal cerebral ischemia induced apoptosis in cortex andhippocampus,4.Metoprolol and Propranolol obviously inhibited focal cerebralischemia-reperfusion injury through down-regulate the expression of Bax and up-regulate the expression of Bcl-2 ,and show a neuroprotective effect.