大鼠急性颅脑损伤后脑微循环的变化

Changes of cerebral microcirculation after acute brain injury in rats

目的 研究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变化的规律 .方法 大鼠 10 0只随机分为 5组 ,采用自由落体致大鼠脑损伤 ,伤后 0 .5 ,3,2 4和 16 8h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 大鼠实验性脑损伤后 0 .5～ 2 4h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 3h已显著增高(P<0 .0 1) ,伤后 2 4h仍然明显高于正常 .胆碱于伤后 3h已有明显升高 ,2 4h达高峰 (P<0 .0 1) .N -乙酰门冬氨酸含量自伤后 3h明显降低 ,伤后 2 4～ 16 8h仍然显著低于正常 (P<0 .0 1) .谷氨酸自伤后 0 .5 h开始明显降低 ,3h降到最低水平(P<0 .0 1) .结论 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。

AIM To evaluate the microcirculatory disturbance of acute brain injury,for finding the factors which affect recovery of brain injury. METHODS One hundred Sprague-dawely rats were randomly divided into 5 groups. Free dropping body led to the brain injury of rats. The morphology of microcirculatory was investigated at 0.5, 3, 24 and 168 h 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 0.5, 24 h after brain injury, while the blood-brain-barrier(BBB) perrmeatibility and brain water content increased. The levels of the Lactate are significantly increased at 3 to 24 h. The levels of choline increased at 3 h, and reached to peaks at 24 h. Reversibly, the levels of N-acetylaspartate were significantly lower at 3 to 168 h. The levels of amino acids glutamate decreased at 0.5, and reached the lowest levels at 3 h after brain injury. CONCLUSION Early disturbances of cerebral microcirculation are the important causes for secondary brain insults after acute brain injury. So, to treat brain injury, we should pay attention to improving the disturbances of cerebral microcirculation and ischemia of brain earlier.