外源性牛磺酸对兔深低温停循环术中脑海马区兴奋性氨基酸的影响

Effects of taurine on early changes of excitatory amino acids in rabbit brain due to deep hypothermic circulatory arrest

目的 观察兔深低温停循环手术中海马区兴奋性氨基酸 (EAA)的变化及外源性牛磺酸对其影响。方法 将 16只成年新西兰白兔随机分为对照组和治疗组,每组 8只,治疗组在建立体外循环前静脉给予牛磺酸 150mg/kg,建立埋植脑微透析装置的体外循环和深低温停循环模型,平衡透析 2h后每 30min取脑海马区细胞间液 1次。采用高效液相色谱紫外检测法,测定兔在麻醉状态、体外循环降温过程中、深低温停循环前 30min、深低温停循环后 30min、复温前 30min、复温后 30min时脑细胞间液中谷氨酸、天门冬氨酸、甘氨酸、牛磺酸的水平变化。结果 对照组谷氨酸在复温前30min、复温后 30min分别是静息状态 ( 5. 1±1 .5 )和 ( 4. 1±1. 4 )倍,高于治疗组的 ( 2 1±1 5 )和(1 1±0 4)倍(t=3 .74, 5. 45,P均<0 .01)。对照组甘氨酸在深低温停循环后 30min为静息状态的6. 7(3. 6, 13. 6)倍,高于治疗组的 4. 2 (3. 8, 11. 5)倍 (T=75 00,P<0. 05)。治疗组的牛磺酸在深低温停循环后 30min时为静息状态的 6. 9(3. 0, 14. 2)倍,高于对照组的 4. 0 (3. 0, 5. 7)倍 (T=75. 00,P<0. 05),复温前 30min时为静息状态的 10. 6 ( 2. 8, 22. 5 )倍,高于对照组的 3. 2 ( 1. 2, 7. 6 )倍(T=90. 00,P<0. 05)。天门冬氨酸在两组间比较差异无统计学意?

Objective To study the effe ct s of taurine (Tau) on early changes of excitatory amino acids(EAA) in hippocam pus rabbit brain due to deep hypothermic circulatory arrest(DHCA). Methods Sixteen New Zealand rabbits were randomly allocated into 2 groups : Tau 150 mg/kg group (group Ⅰ ,n=8), control group (group II,n=8 ). Cardiac pulmonary bypass(CPB) was set up after cerebral microdialysis mode l was established. High performance liquid chromatography was employed to moni tor the continuous changes of glutamic acid(Glu), aspartic acid(Asp), Tau and glycin(Gly) in the hippocampus CA1 region at anaesthesia periods, CPB stage, pre 30 minutes in DHCA, post 30 minutes in D HCA, pre 30 minutes in rewarming, post 30 minutes in rewarming. Results The increase of Glu in group Ⅱ was (5.1±1.5) and (4.1±1.4 ) times higher than that at anaesthesia periods(t=3.74,5.45,P<0.01 ) , and the increase of Glu in group Ⅰ was (2.1±1.5) and (1.1±0.4)times than that at anaesthesia periods at pre 30 minutes and post 30 minutes rewming stage respectively. Rising of Gly in group Ⅱ was 6.7(3.6,13.6)times than tha t at anaesthesia periods (T=75.00,P<0.05),the rising of Gly in gro up I was 4.2(3.8,11.5)times at post 30 minutes in DHCA. Rising of Tau in grou p Ⅰ was 6.9(3.0,14.2)and 10.6(2.8,22.5)times than that at anaesthesia per iods(T=75.00,P<0.05 and T=90.00,P<0.05) and rising of Tau in group Ⅱ was 4.0(3.0,5.7)and 3.2(1.2,7.6)times than that at anaesthesi a periods at post 30 minutes in DHCA and pre 30 minutes rewarming stage respect ively. Asp was no evident change at every periods. Conclusion DHCA might increase the excitatory amino acids in the early phases of circulatory restoration.Exterior Tau 150 mg/kg could inhibit release of EAA .