The changes of spinal blood flow and neurotransmitters after experimental spinal cord injury in rabbits.

近年来，脊髓损伤后脊髓微循环的变化以及内源性兴奋性氨基酸在脊髓损伤后瘫痪发病机制中的作用已得到系统认识。在这项研究中，比较兴奋性氨基酸受体(NMDA)拮抗剂MK801对兔脊髓损伤后微循环和单胺类物质水平的影响，并与对照组(对照组)进行比较。研究内容包括：1)根据Talov‘s评分评价运动瘫痪；2)激光多普勒血流仪测定脊髓血流量；3)干重法测定脊髓水肿；4)微量测定荧光物质(FD 70)，检测脊髓内血管通透性的变化；5)高效液相色谱-电化学检测法测定脊髓内单胺类物质及其代谢产物。结果1)MK801治疗组运动瘫痪在伤后24小时明显改善。2)创伤后脊髓血流量显著减少。3)MK801治疗组脊髓损伤后1小时和6小时的脊髓水肿程度明显低于对照组。4)MK801治疗组脊髓内血管通透性的增加在伤后1小时显著低于对照组。5)MK801治疗组的MHPG/NE比值明显高于对照组。因此，NMDA在继发性脊髓损伤中起重要作用。

The changes in spinal micro circulation and the effects of endogenous excitatory amino acid on the pathogenic mechanism of paralysis after acute spinal cord injury were system have been recognized in recent years. In this study, various factors concerning microcirculation and monoamines levels were compared between rabbits in which excitatory amino acid receptor (NMDA) antagonist MK801 administerd (MK801-treated group) and untreated controls (control group) after spinal cord injury.The following studies were performed.1)Evaluation of motor paralysis according to the Talov's evaluation.2)Determination of the spinal blood flow by laser doppler flowmetry.3)Quantitative determination of spinal edema by the dry weight method.4)Microdetermination of fluorescent materials (FD 70S) to detect changes in intraspinal vascular permeability.5)Determination of intraspinal monoamines and their metabolites by HPLC with electrochemical detection.Results1)Motor paralysis improved significantly in the MK801-treated group after 24 hours.2)Spinal blood flow was decreased after trauma substantially, but there was no signficant difference between the two groups during 6 hours after injury.3)Severity of the spinal edema in the MK801-treated group was significantly less than that in the control group, 1 hour and 6 hours after injury.4)An increase in intraspinal vascular permeability in the MK801-treated group was significantly less than that in the control group, one hour after injury.5)MHPG/NE ratio was significantly greater in the MK801-treated group than in the control group.The present study revealed that NMDA antagonist MK801 improved behavioral outcome, spinal edema, and vascular permeability after acute spinal cord injury. Therefore it was strongly suggested that NMDA plays an important role in the secondary spinal cord damage.