The Neuroprotection Of Estrogen In Cerebral Ischemia

Background and purpose: Ischemic cerebral vasculardisease is one of the serious factors which threaten humanbeings lives. The infarction lesion is made up of central necrosisand peripheral penumbra. Nowadays, a few patients can betaken thrombolysis if they come to hospital in 6 hours afteronset. At the same time, the neuroprotectant is important on theacute stage. Both retrospective and prospective epidemiologicalstudies have demonstrated beneficial effects of estrogenreplacement therapy in reducing stroke –related mortality that isassociated with stroke in postmenopausal women. Estrogen hasbeen reported to exert neuroprotective effects whenadministered before all ischemic insult. This study was designedto determine whether estradiol treatment after middle cerebralartery occlusion exerts the same effects and its effect on theexpression of apoptotic gene bcl-2,bax.Methods: Male wistar rats were subjected to permanentmiddle cerebral artery occlusion. 48 male Wistar rats, aged from2-3 months and weighing 230-250g, were randomly divided intoTTC stain group and apoptotic group. Each group wassubdivided into 3 groups:(n=8 in each group)1,saline group 2,estradiol group 3 ,pseudo-operation group. Estradiol wasadministered 1mg/Kg by intraperitoneal injection and salinegroup was given saline. One week later, all rats were subjectedto permanent middle cerebral artery occlusion and were killed at24h after cerebral ischemia. MCAO animal mode was made bynylon suture. Behavior changes of t he experimental animalwere determined by Zea longa score at 4,8 and 24 hours. Thesize of infarction was showed by TTC stain.Immunohisto-chemistry was used to show the expression ofbcl-2 and bax. The bcl-2 and bax positive cells were counted inthe cerebral cortex and corpus striatum. SAS statistics softwarewas used to analyze data, ANOVA and student T test wereadopted in data and analysis.Results: 1,The E2 group neurodeficit score was lower thanthe saline group at 8,24 hours which were significant (P〈0.05〉.2,The ischemic lesion volume of E2 group was smaller thansaline group(P<0.05). 3,The expression of bcl-2 was moreevident in E2 group, but the expression of bax was not evidentcompare with saline group, it was significant(P<0.05).Conclusion: 1,Animal model made by suture method wasstable and corresponded to the requirement for study. 2,Estradiol can reduce the ischemic lesion volume.3,Estradiol canincrease the expression of anti-apoptotic bcl-2 gene and inhibit...