Zhang Y, Hillered L, Olsson Y, Holtz A
Laboratory of Neuropathology, University Hospital, Uppsala, Sweden.
Surg Neurol. 1993 Apr;39(4):297-304. doi: 10.1016/0090-3019(93)90009-p.
Changes occurring in the extracellular fluid (ECF) concentration of energy-related metabolites were investigated in a well-characterized model of compression trauma to the spinal cord. Microdialysis probes were inserted into exposed grey matter of the dorsal horn at the level of Th 7-8, and perfused with mock cerebrospinal fluid. The trauma was produced 2 hours later by compression of the cord with a 9-, 35-, or 50-g load for 5 min. Microdialysis samples (10-minute fractions) were collected for another 2 hours following decompression. The trauma was associated with an accumulation of lactate, inosine, and hypoxanthine, and an increase in the lactate/pyruvate ratio in the ECF, indicating a profound disturbance in energy metabolism. These changes were related to the severity of spinal cord injury as well as to the spinal cord blood flow (SCBF) reductions and neurological deteriorations previously determined. Following decompression, all ECF metabolites normalized within 20-40 min after mild (9 g) to moderate (35 g) trauma. After severe trauma (50 g), resulting in complete ischemia during compression, followed by irreversible paraplegia, there was a partial recovery of ECF inosine and hypoxanthine, whereas the increase in lactate and the lactate/pyruvate ratio persisted. The results suggest that penumbra conditions prevail during the early posttraumatic period when the degree of trauma results in severe neurological deterioration and that ECF lactate levels in the spinal cord is a sensitive indicator of secondary ischemia after compression injury.
在一个已充分表征的脊髓挤压伤模型中，研究了细胞外液（ECF）中与能量相关代谢物的变化。将微透析探针插入胸段7 - 8水平暴露的背角灰质中，并用模拟脑脊液进行灌注。2小时后，用9克、35克或50克的负荷对脊髓进行5分钟的挤压以造成损伤。减压后再收集2小时的微透析样本（10分钟的馏分）。该损伤与乳酸、肌苷和次黄嘌呤的积累以及ECF中乳酸/丙酮酸比值的增加有关，表明能量代谢存在严重紊乱。这些变化与脊髓损伤的严重程度以及先前确定的脊髓血流量（SCBF）减少和神经功能恶化有关。减压后，轻度（9克）至中度（35克）损伤后，所有ECF代谢物在20 - 40分钟内恢复正常。严重损伤（50克）导致挤压期间完全缺血，随后出现不可逆的截瘫，ECF中的肌苷和次黄嘌呤有部分恢复，而乳酸增加和乳酸/丙酮酸比值持续存在。结果表明，当创伤程度导致严重神经功能恶化时，创伤后早期存在半暗带状态，并且脊髓中的ECF乳酸水平是挤压伤后继发性缺血的敏感指标。
