急性局灶性脑挫裂伤对大鼠脑微循环及神经组织超微结构的影响

The Influence of Acute Brain Regional Contusion and Lace-Ration of the Brain on Cerebral Microcirculation and Ultrastructure of Nervous Tissue in Rats

目的：探讨大鼠脑损伤后脑微循环障碍、脑缺血及神经组织超微结构的变化规律,为临床改善脑损伤后脑微循环障碍、治疗脑缺血、促进神经功能恢复提供理论依据。方法：采用Feeney＇s自由落体撞击法建立急性局灶性脑挫裂伤模型,共81只大鼠,随机均分为9组,每组6只行内源性过氧化物酶（EGPO）组织化学染色、脑含水量测定,并进行图象分析。每组3只电镜观察微血管内皮细胞和神经组织超微结构改变。结果：①脑损伤后30min伤区可见出血灶,伤区内无血管染色,伤区周围存在“微无血管区”。“微无血管区”的存在持续至伤后72h。②脑损伤后30min微血管面密度明显下降,伤后48h达到高峰,直到伤后168h才有所恢复,但仍未达到正常水平。③脑损伤后30 min微血管平均光密度明显下降,伤后24h、48h回升,72h再次下降,至168h仍未恢复正常。④脑损伤后30 min,微血管内皮细胞有轻度受损迹象,伤后2h毛细血管腔内有微绒毛形成,伤后6h微绒毛增多。伤后12-72h毛细血管腔明显狭窄。⑤脑损伤后30min,神经细胞超微结构改变不明显,随时间的延长,神经细胞超微结构逐渐恶化,至伤后168h细胞结构完全丧失。结论：EGPO组织化学染色方法能准确反应脑损伤后脑微循环的改变;脑损伤后即发生脑缺血改变,神经细胞、毛细血管内皮细胞的损害继发于脑损伤后的缺血性改变,而脑缺血的发生源于脑损伤后脑微血管结构的破坏和微循环灌注的不足。

Objective：To explore the alteration law of cerebral microcirculation, the cerebral ischemia and the ultrastructure of nervous tissue after brain injury,to furnish evidence for improving the disturbance of cerebral microcirculation after brain injury and treat the cerebral ischemia. Methods： Acute regional brain trauma was obtained by Feeney＇s apparatus. Six cases in each group were performed endogenous peroxidase （EGPO） histochemical staining,water content of the brain and the charts were analyzed by CMIAS system. Three of them were observed on the alteration of the micro-angium endotheliocyte ultrastructure and nervous tissue. Results：The hemorrhage was observed at the traumatic area and the blood vessel was not stained around the traumatic area, ＂non＂ or ＂less＂ rnicrovessels area was showed and it continued 72h. The density of microvasculature volume fraction declined at 30min. It reached peak at 48h and resumed at 168h. The MOD declined at 30min,raised again at 48h and 72h, declined again at 168h. The micro-angium endotheliocyte was damaged at 30min, the microvilli was formed at 2h and 6h,and the cavum of micrangium was narrowed at 12-72h. The ultrastructure of nervous tissue gradually worsened after brain injury. Conclusion： EGPO histochemical staining could reflect correctly the changes of cerebral microcirculation. The brain ischemia appeared early after brain injury,which subsequently interferes with microvascular structure and hypoperfusion of microcirculation. The damage of nervous cell and micro-angium endotheliocyte result in the brain ischemia,which subsequently interfere microvascular structure and hypoperfusion of microcirculation.