实验性脑缺血模型脑组织微血管P-选择素表达的研究

Study on P-selectin expression of micro-vessels in experimental ischemic encephalopathy model

目的:研究不同缺血时间兔脑组织微血管P-选择素表达的变化,探讨其临床价值。方法:新西兰白兔34只随机分实验组、对照组。实验组股动脉穿刺插管至颈内动脉后造影,经导管注入自体血栓选择性栓塞大脑中动脉建立急性脑梗死模型。按缺血时间不同分为1小时、3小时、6小时、12小时、24小时5个亚组,确认兔急性脑梗死模型建立成功后对缺血脑组织进行免疫组织化学检查,观察P-选择素表达的动态变化。对照组手术步骤同上,仅予以造影观察血管是否通畅。结果:对照组兔脑组织微血管未见P-选择素的表达。缺血1小时组缺血侧脑组织微血管P-选择素开始表达犤阳性血管数(55±18)条犦,1小时、3小时及6小时组缺血侧脑组织微血管P-选择素逐渐升高,各组间阳性血管数有显著性差异(P<0.01),6小时组缺血侧脑组织微血管P-选择素表达到高峰犤阳性血管数(417±28)条犦并持续到24小时犤阳性血管数(428±62)条犦,6小时、12小时及24小时组微血管P-选择素表达无显著性差异(P>0.05)。缺血1小时、3小时及6小时组各组间缺血侧皮质P-选择素表达明显高于髓质(P<0.05),而12小时、24小时组皮质与髓质P-选择素表达无显著性差异(P>0.05)。对侧大脑半球(非缺血侧)缺血1小时、3小时均未见P-选择素表达,而6小时、12小时、24小时可见有少量P-选择素表达?

Objective To study the expression of P-selectin of micro vessels of the ischemic cerebrum of rabbits at different time and explore its clinical value. Methods New Zealand rabbitsn=34 were randomly divided into two groups experimental group and control group. In experimental group a catheter was introduced into the internal carodid artery through femoral artery. After internal carotid arteriography thrombus from themselves were injected to embolize their middle cerebral artery. Then the experimental group was divided into five groups1 hour group 3 hour group 6 hour group 12 hour group 24 hour group according to the different ischemic time. The models in the experiment were proved to be established successfully. Immunochemistry technology was used to study the expression of P-selectin on micro-vessels of the ischemic brain. In control group all the procedures did as operation group except did not selectively embolize their middle cerebral artery we observed whether the vessels open or not by internal carotid arteriography. Results In control group no expression of P-selectin on micro vessels of the bilateral cerebrum. In 1 hour group the expression of P-selectin on micro vessels of ischemic cerebrum was observedthe number of positive vessels55±18. And was gradually increased in 3 hour group and 6 hour group between which the difference was very significant(P<0.01). In 6 hour group the expression of P-selectin reached its top peakthe number of positive vessels417±28 and remained top peak in 12 hour groupthe number of positive vessels416±72 and 24 hour groupthe number of positive vessels428±62 between which the difference was not significant(P>0.05). It was found that the expression of P-selection on micro vessels in cerebral cortex was higher than that in the medulla in 1 hour 3 hour and 6 hour groups between which the difference was significant(P<0.05) but among 6 hour 12 hour and 24 hour groups the difference was not significant(P>0.05). In 6 hour groupthe number of positive vessels34±12 12 hour groupthe number of positive vessels52±13 and 24 hour groupthe number of positive vessels51±16 we had also found the expression of P-selectin on micro vessels on the other side of nonischemic cerebrum but its expression was lower. Conclusion After middle cerebral artery occlusionMCAO it suggest that the potential thrombolytic therapeutic time window in rabbit is within 6 hours.