The Expression Of BDNF And TrkB On The EBI After Subarachnoid Hemorrhage And The Study Of The Changs Of Myelin Sheath In Rat

Objectives：1. To investigate the that the effect of neurological deficits and the edemaof brain on the EBI after SAH(≤3d) in rats.2. To observe the level of apoptosis of nerve cells and the changs ofmyelin sheath on the EBI after SAH in rats and dicuss the effects of bothof two in the pathological and function on the EBI.3.To observe the expression of Brain Derived Neurotrophic Factor(BDNF)and tropomyosin-related kinase B (TrkB) on the EBI after SAH in rats,in order to study the neuroprotection of BDNF and TrkB and therelations between the expression of BDNF and TrkB and EBI.Methods：1. SAH was induced by endovascular perforation of the internal carotidartery (ICA) bifurcation with a sharpened3-0nylon suture,MaleSprague-Dawley rats (n=64) weighing280to320g，were randomlydivided into sham groups (n=32) and SAH groups (n=32),both of thetwo groups including24h and72h, each group have16rats, a steadymodel of EBI after SAH in rats that produced by endovascularperforation of internal carotid artery, random added If the rats died, toensure the sample numbers of each group. All of the rats wereperfusion-fixed or anesthesia beeheaded put to death directly.sectionedslices of6rats from each group were examined by HE staining toobserve the pathological changes of brains,after that were used to IHCand TUNEL,8rats from each group were beheaded executed quicklyinto the liquid nitrogen preservation,for the use of ELISA. theultrastructural changes of the brain axon and myelin sheath of2ratsfrom each group were examined by TEM.2. The grouping was similar to the first part. TUNEL technique and TEM technique were used to observe apoptosis of nerve cells and the changs ofmyelin sheath in the brain after SAH in rats.3. The grouping was similar to the first part. Immunohistochemicaltechnique and ELISA technique were used to observe the expressions ofBDNF and TrkB in the brain.Results：1. The mortality rate of the SAH model was49.20%in3days,Neurologicaldefieits were observed after SAH, The edema of SAH groups is seriousobviously comparing to the control group.2. TUNEL revealed the apoptotic cell was little in the brain of the shamgroups and began to appear in24h after SAH，then the apoptotic level wasgradually rising in the72h.3. The results of TEM in SAH groups showed some ultrastructural changesin brain, including neurons cytolysis necrosis, axon swelling, myelinsheath layer stripping, the infiltration of abundant neutrophilic granulocyteand monocyte in brain.4. The results of IHC and ELISA show that BDNF and TrkB of the shamgroups have a small amount of expression,the24h group of SAH groupswas rising comparing to Sham group（P＜0.05）, and it was the mostsignificant expression in72h after SAH（P＜0.05）Conclusions:1.It was stable and reliable that used SD rat by internal carotid arteypuncture to establish SAH model, which was appropriate for investigatingmechanism and therapeutic approaches in EBI after SAH.2. Brain injury,apoptosis and myelin sheath layer stripping in brain existedin this model,they played important roles in the physiological andpathological changs of early brain injury after subarachnoid hemorrhage.3. The expression of BDNF and TrkB increased significantly afterSAH,which had certain regularity time, BDNF and TrkB may involve inthe process of neurons apoptosis and the occurrence of EBI after SAH.