大鼠脑缺血再灌注后不同时间段中枢组织 ACTH样蛋白表达变化

目的采用免疫细胞化学技术,探讨大鼠脑缺血再灌注后不同时期中枢几个重要脑区促肾上腺皮质激素样阳性免疫物的表达变化。方法雄性Wistar大鼠70只,随机分成正常对照组、假手术对照组、脑缺血再灌注组。以颈动脉引流法行全脑缺血再灌注造模,术后分6h、24h、72h三个时间段取脑,脑组织恒冷箱连续冠状切片,免疫细胞化学ABC反应,图像分析系统行顶皮质1区、下丘脑室旁核、丘脑室旁核、海马CAl区促肾上腺皮质激素样阳性免疫面积、平均吸光度检测。结果镜下观察,促肾上腺皮质激素样阳性免疫物呈深棕色,深染胞核广泛分布于中枢皮质、海马、丘脑及下丘脑等各脑区,核仁清晰可辩。在丘脑及下丘脑区域散在分布有“串珠”状阳性纤维。图像分析结果显示,假手术对照组、脑缺血再灌注组两组阳性免疫面积和平均吸光度值呈同步变化。从术后6h开始,假手术对照组、脑缺血再灌注组两组均较正常对照组显著升高,术后24h达高峰(P<0.05),然后逐渐回落。在三个不同时间段,三组间均存在显著差异(P<0.05),术后6h及24h脑缺血再灌注组>假手术对照组>正常对照组;术后72h假手术对照组>正常对照组>脑缺血再灌注组。结论在脑缺血再灌注不同时间段,中枢神经元促肾上腺皮质激素样阳性免疫物表达呈现明显的时间规律;促肾上腺皮质激素可能在神经元功能调控、中枢内环境控制及脑缺血再灌注损伤过程中发挥重要作用。

Alterations in protein expression of ACTH during reperfusion after ischemia in the rat brain

Objective:By immunohistochemistry and compute-assisted image analysis,We investigated the changes in protein expression of ACTH levels in rat brain during reperfusion after ischemia. Methods: 70 male wistar rats randomly divided into 3 groups: normal control group (n=10),sham-ischemia group(n=30), cerebral ischemia-reperfusion group(n=30). Temporary cerebral ischemia-reperfusion injury model was established by using common carotid artery blood drainage Methods: Brain section was obtained by cryostat sectioning. The section was prepared for ACTH immunohistochemistry staining and was observed by optical microscope. Quantitate analysis was carried out for ACTH immunoreactive matter stain area and density. Results: During ischemia reperfusion, The expression of ACTH protein in brain is increased sharply at 6h and 24h, and fallback to the control level at 72h. Conclusions:The present results demonstrate that the sharply expression of ACTH protein in brain at early reperfusion might be one of the mechanism for delayed brain ischemia reperfusion injury.