Stoffel M, Eriskat J, Plesnila M, Aggarwal N, Baethmann A
Institute of Surgical Research, Klinikum Grosshadern, Ludwig-Maximilians-University, Munich, Federal Republic of Germany.
Acta Neurochir Suppl. 1997;70:91-3. doi: 10.1007/978-3-7091-6837-0_28.
A cortical tissue necrosis from focal trauma expands to 150% of its initial volume within 24 hrs. It is currently unknown, whether this phenomenon is part of the primary traumatic lesion or if it involves secondary mechanisms such as the release of excitatory amino acids into the traumatic penumbra zone. A microdialysis probe was inserted for that purpose in an oblique angle into the cortex of Sprague-Dawley rats, approximately 2 mm below the brain surface. One day later a highly standardized cortical freezing lesion was induced at the brain cortex above the microdialysis probe. Dialysate was collected prior to, during, and after trauma in 10 min intervals. In each animal, it was confirmed histologically, that the tip of the microdialysis probe was localized in the grey matter in close vicinity to the primary lesion. Following induction of the trauma a statistically significant increase of the dialysate level of aspartate, glutamate, glycine, and serine was observed, whereas that of alanine was not altered throughout the experiment. The posttraumatic increase of the excitatory neurotransmitters aspartate and glutamate indicates that these amino acids are involved in the secondary lesion growth after trauma. Confirmation of this hypothesis would require that specific antagonization of these excitotoxic amino acids is inhibiting growth of the lesion.
局灶性创伤引起的皮质组织坏死在24小时内扩展至其初始体积的150%。目前尚不清楚这种现象是原发性创伤性病变的一部分，还是涉及继发性机制，如兴奋性氨基酸释放到创伤半暗带区域。为此，将一个微透析探头以倾斜角度插入Sprague-Dawley大鼠大脑皮质，距脑表面约2毫米处。一天后，在微透析探头上方的大脑皮质诱导高度标准化的皮质冷冻损伤。在创伤前、创伤期间和创伤后，每隔10分钟收集一次透析液。在每只动物中，通过组织学确认微透析探头尖端位于靠近原发性病变的灰质中。创伤诱导后，观察到透析液中天冬氨酸、谷氨酸、甘氨酸和丝氨酸水平有统计学意义的升高，而丙氨酸水平在整个实验过程中未发生改变。创伤后兴奋性神经递质天冬氨酸和谷氨酸的增加表明，这些氨基酸参与了创伤后的继发性病变生长。要证实这一假设，需要特异性拮抗这些兴奋性毒性氨基酸能抑制病变生长。
