大鼠急性颅脑损伤后脑微循环变化的实验研究

Changes of cerebral microcirculation after acute brain injury in rats

目的 研究大鼠急性颅脑损伤后脑微循环的改变，以找出影响颅脑损伤与恢复的变化规律。方法 １００只大鼠随机分为５组，自由落体致大鼠脑损伤，伤后３０分钟、３小时、２４小时、１６８小时取材，研究脑微血管形态学变化，并用核磁共振波谱法分析颅脑损伤局部脑组织代谢的变化。结果 大鼠脑损伤后１０分钟～２４小时大脑皮层微血管减少，并有“微无血管区”，微血管内可见微血栓形成；血脑屏障（ＢＢＢ）通透性增加，出现脑水肿，颅脑损伤后伤区脑组织乳酸含量于伤后３小时显著增高（Ｐ＜０．０１），伤后２４小时仍然明显高于正常值。胆碱于伤后３小时明显升高，２４小时达高峰（Ｐ＜０．０１）。Ｎ乙酰门冬氨酸含量自伤后３小时明显降低，伤后２４～１６８小时仍然显著低于正常值（Ｐ＜０．０１）。谷氨酸自伤后３０分钟开始明显降低，３小时降至最低水平（Ｐ＜０．０１）。结论 实验结果提示，颅脑损伤后微循环障碍是引起早期脑缺氧，产生外伤性脑水肿的重要病理基础，救治重型颅脑损伤要重视防治早期脑微循环障碍，纠正脑缺血、缺氧。

Objective To evaluate the microcirculatory disturbance in acute brain injury for finding the factors affecting recovery of brain injury.Methods One hundred Sprague-Dawely rats were rando mly divided into 5 groups.Free dropping body lead to the brain injury of rats.The morphology of microcirculatory was investigated at 30 minutes,3 hours,24 hours and 168 hours after acute brain injury in rats,and metabolism of brain by magnetic resonance spectroscopy was measured.Results The 'non'or 'less' microvessels areas and microthrombus in injured cerebral cortex were found at 30 minutes,24 hours after brain injury,while the blood-brain-barrier(BBB )permeatibility and brain water content were increased.The levels of the lactate were significantly increased at 3 hours to 24 hours.The levels of choline were increased at 3 hours,reached to peaks at 24 hours.On the other hand,the levels o f N-acetylaspartate were significantly lower at 3 hours to 168 hours.The levels of amino acids glutamate were decreased at 30 min,and reached to the lowest levels at 3 hours after brain injury.Conclusion These results sugg ested that early disturbances of cerebral microcirculation were the important re ason of secondary brain insults after acute brain injury.More attention should be peid to improve the disturbances of cerebral microcirculation and ischemia of brain in earlier stage.