缺氧缺血时新生大鼠脑中谷氨酸含量的变化及与脑损伤的关系

目的建立单侧缺氧缺血性脑损伤 (hypoxic ischemicbraindamage,HIBD)动物模型 ,研究HIBD时脑中谷氨酸含量的变化及意义。方法选择 7日龄Wistar大鼠 5 6只 ,建立HIBD模型 ,随机分成假手术 2 4、4 8、72h组和HIBD 2 4、4 8、72h组及正常对照组 ,每组 8只 ,制模前观察每只大鼠的夹尾左旋及翻身能力。各组于规定时刻断头处死 ,留取脑标本检测 :HE或阿新兰 (Alicanblue)染色观察脑形态学改变 ;高效液相色谱分析电化学检测法(highperformanceliquidchromatography ,HPLC)测定脑谷氨酸 (glutamate ,Glu)含量 ;流式细胞仪 (flowcytometry ,FCM )检测脑同一区域凋亡细胞计数。结果制模前各组大鼠行为检查均正常 ;制模后 1hHIBD各组 15只不能翻身 ,19只出现夹尾左旋 ,两者均有 11只。与同时刻假手术组比较 ,HIBD各组脑组织神经元细胞变性、坏死 ,树突减少或消失 ,脑软化灶形成 ,小胶质细胞增生 ,以 72h组最明显 ;HIBD 4 8h组Glu含量明显升高 ;HIBD各组凋亡细胞计数明显增加 (P均 <0 .0 5 )。结论缺氧缺血损伤了大鼠的运动中枢 ,缺氧缺血后 4 8h脑中Glu含量的短暂升高与脑组织病理损害、神经细胞凋亡密切相关 ,提示脑中Glu含量的升高在HIBD的发病过程中具有重要作用 ,降低脑中Glu含量是改善HIBD的关键。

EFFECT OF HYPOXIA-ISCHEMIA ON GLUTAMATE IN BRAIN OF NEONATAL RATS AND ITS DAMAGE

ObjectiveTo study the effect and significance of hypoxia-ischemia on glutamate in brain of neonatal rats on single side of hypoxia-ischemia animal models.MethodsFifty-six Wistar rats aged seven days were randomly divided into: sham control24, 48, 72 h and hypoxic-ischemic brain damage(HIBD) 24, 48, 72 h and normal control groups, respectively. There were 8 rats in each group. At directed time, the rats were decapitated, and the histological feature and levels of glutamate and levels of apoptosis were observed. Hematoxylin-eosin stating (HE) or Alican blue stating was used for observation of the brain morphological changes. High-performance liquid chromatography and electrochemical determination were used for the brain glutamate. Flow cytometry was used for apoptosis count of the same region in the brain. ResultsCompared with sham group for different points of time, HIBD group showed severe damage, as cell degeneration, necrosis and less or lack of drendrites, cerebral softened focus, hyperplasia of samall gliocyte and at 72 h the group showed most obviously. HIBD group at 48 h showed more increase of glutamate, all the HIBD group showed obviousincrease of apoptosis count (P< 0.05). ConclusionAt 48 h of hypoxia-ischemia, the brain shows a temparal increase of glutamate, which associates closely with histopathological injury of the brain and the apoptosis. Glutamate increase in the brain plays an important role in pathogenesis of HIBD. The key is to decrease the brain glutamate for improving HIBD.