脑微透析法研究鼠脑损伤后脑局部生化代谢的变化

Regional Biochemical Changes Following Brain Injury in Rats: A Microdialysis Study

目的 研究鼠脑损伤后脑局部生化代谢的变化 ,探讨微透析技术在监测脑损伤局部生化代谢改变中应用潜力。方法 将SD大鼠分为对照组和损伤组 ,损伤组包括轻度损伤组和重度损伤组 ,运用微透析技术分别监测其脑细胞外液 (ECF)中葡萄糖和乳酸含量的改变。结果 脑细胞外液透析液中葡萄糖含量 ([Gluc]d)在轻度、重度损伤组的最低值分别为伤前基础值的 (6 5± 6 ) %、 (36± 9) %。轻度损伤组伤后 [Gluc]d降低 ,持续至 6 0min后基本接近伤前基础水平 ,重度损伤组伤后 12 0min仍显著低于伤前基础水平 ,伤后各时段重度损伤组比轻度损伤组明显降低 (均为P <0 0 5 )。脑细胞外液透析液中乳酸含量 ([Lac]d)损伤组为伤前基础值的 (4 85± 4 5 ) % ,伤后各时段重度损伤组比轻度损伤组明显升高 (均为P <0 0 5 )。随着损伤程度增加伤侧脑组织含水量亦明显增加 ,各损伤组之间均存在明显差异 (均为P <0 0 5 )。结论 本研究提示伤后脑细胞外液中葡萄糖和乳酸水平的变化 ,可以作为判断伤情和继发性脑水肿程度的重要生化指标。

Objective To explore the regional changes following traumatic brain injury (TBI) and study the potential of microdialysis in monitoring the concentration changes of glucose and luctate in extracellular fluid (ECF) after TBI. Methods The SD rats were divided into two groups: control group and TBI group (including mild TBI group and severe TBI group). Microdialysis was applied to monitor the changes of glucose and luctate in ECF. Results The lowest values of cerebral ECF glucose in micodialysis (\ d) in the mild TBI group and severe TBI group were reduced to (65±6) % and (36±9) % of basic values respectively. In mild TBI group \ d was returned to basic value in 60 min, while it was still much lower than the basic value in 120 min in severe TBI group. The \ d in severe group was remarkably lower than in mild TBI group at different time points (all P<0.05). The contents of cerebral ECF luctate in microdialysis (\ d) were elevated to (485±45) % of the basic value after TBI . The \ d in severe TBI group was obviously higher than in mild TBI group at different time points (P<0.05). The peak concentrations of glucose and lactate were correlated with the content of the brain water. Conclusion Microdialysis is an ideal and feasible method for dynamic sampling of neurochemical substances from the extracellular space of the brain following TBI. Increased lactate and decreased glucose maybe indicate accelerated glycolysis in TBI. The changes of lactate and glucose in the cerebral ECF following TBI are two important bichemical parameters which could be used to determine the severity of TBI and predict the outcomes.