Kozler Petr, Riljak Vladimír, Pokorny Jaroslav
Department of Neurosurgery, First Medical Faculty, Charles University, Prague, Czech Republic.
Neuro Endocrinol Lett. 2010;31(4):477-82.
Clinically very serious condition of ischaemia and brain injury which are often associated with brain oedema is frequently accompanied by the impairment of the structural integrity of axons. We wondered whether the brain oedema (without ischemia brain injury) can induce structural axonal impairment.
Brain oedema was induced by osmotic blood-brain barrier opening with 20% mannitol applied selectively into the internal carotid. Axonal changes were recognized as signs of myelin disintegration (oedematous vesicles, varicosity, myelin fragmentation) at histological sections stained with Black Gold in hippocampal areas CA1 and CA3 and in the dentate gyrus and cerebral cortex at time intervals of one hour, one day, three days and one week after the oedema induction.
Impairment of the structural integrity was identified in myelin sheets in all areas studied in all experimental groups. Whereas in the control group axon were of the uniform diameter, in the experimental groups various forms of myelin disintegration were observed. The progression of myelin damage depended on the time elapsed after the oedema induction.
Opening the blood-brain barrier with an osmotic insult induces brain oedema which represents a factor triggering axonal impairment accompanied with myelin changes. The development of axonal changes initiated by brain oedema only (without ischemia brain injury) is a novel observation.
临床上非常严重的缺血和脑损伤常伴有脑水肿，且常常伴随着轴突结构完整性的损害。我们想知道脑水肿（无缺血性脑损伤）是否会导致轴突结构受损。
通过将20%甘露醇选择性注入颈内动脉造成渗透性血脑屏障开放来诱导脑水肿。在诱导脑水肿后的1小时、1天、3天和1周的时间间隔，在海马CA1区和CA3区、齿状回以及大脑皮质，用黑金染色的组织切片上，轴突变化被识别为髓鞘崩解的迹象（水肿性囊泡、静脉曲张、髓鞘碎裂）。
在所有实验组研究的所有区域的髓鞘中均发现结构完整性受损。对照组轴突直径均匀，而实验组观察到各种形式的髓鞘崩解。髓鞘损伤的进展取决于诱导脑水肿后的时间。
渗透性损伤打开血脑屏障会诱发脑水肿，这是一个引发轴突损伤并伴有髓鞘变化的因素。仅由脑水肿引发的轴突变化（无缺血性脑损伤）的发展是一项新的观察结果。
