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目的探讨脑损伤后脑微循环障碍变化规律,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81只Wistar大鼠随机分为对照组(n=9)和脑损伤组,损伤组按伤后不同观察时相点又分为8个亚组,每亚组9只。采用Feeney’s自由落体撞击法建立急性局灶性脑挫裂伤模型。每组6只行内源性过氧化物酶(EPOD)组织化学染色、脑含水量测定,并进行图像分析。余3只电镜观察微血管内皮细胞超微结构改变。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3 d。(2)脑损伤后30 min微血管面密度明显下降,伤后2 d达到高峰,直到伤后7 d才有所恢复,但仍未达到正常水平。(3)脑损伤后30min微血管平均光密度明显下降,伤后24h、2 d回升,3 d再次下降,至7 d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2 h毛细血管腔内有微绒毛形成,伤后6 h微绒毛增多。伤后12 h～3 d毛细血管腔明显狭窄。结论EPOD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,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不足。
Objective To investigate the changes of cerebral microcirculation disturbance after brain injury and to provide a theoretical basis for clinical improvement of cerebral microcirculation disturbance, treatment of cerebral ischemia and promotion of neurological function recovery. Methods Totally 81 Wistar rats were randomly divided into control group (n = 9) and brain injury group. The injury group was divided into 8 subgroups at 9 different subgroups. The acute focal cerebral contusion model was established by Feeney’s free-fall impact method. Six rats in each group were subjected to endogenous peroxidase (EPOD) histochemical staining, brain water content determination, and image analysis. Ultrastructural changes of microvascular endothelial cells were observed with three electron microscopes. Results (1) Hemorrhagic lesions were seen in the injured area 30 min after brain injury. There was no vascular staining in the injured area and there was microvascular area around the injured area. Micro-avascular area persisted until 3 days after injury. (2) Microvessel density decreased obviously 30 min after brain injury and peaked on the 2nd day after injury. It recovered only 7 days after injury, but still did not reach the normal level. (3) The average optical density of microvessels decreased obviously 30 min after brain injury, rose at 2 and 2 d after trauma, declined again at 3 d, and remained normal after 7 days. (4) 30 min after brain injury, microvascular endothelial cells showed slight signs of damage. Microvilli formed in the capillary cavity 2 h after injury, and microvilli increased 6 h after injury. After 12 h ~ 3 d, the capillaries were stenosed obviously. Conclusion EPOD histochemical staining can accurately reflect the changes of cerebral microcirculation after brain injury. Cerebral ischemia occurs after brain injury, and the occurrence of cerebral ischemia results from the destruction of cerebral microvascular structure and insufficient perfusion of microcirculation after brain injury.