【摘要】 目的:探讨低温对离体大鼠海马脑片缺氧无糖(oxygenandglucosedeprivation,OGD)损伤的保护作用及其机制。方法:①观察大鼠海马脑片在OGD条件下顺向群峰电位(orthodromicpopulationspike,OPS)的变化及温度对它的影响。②观察谷氨酸(Glu)对海马脑片OPS的影响及低温的抗Glu毒性作用。并在人工脑脊液(ACSF)中分别加入GABA R的特异性阻滞剂bicuculline(BMI)和NMDA R的特异性阻滞剂D()2Amino5phospho nopentanoicAcid(AP5)或加入BMI和非NMDA R阻滞剂6,7Dinitroquinoxaline2,3(1H,4H)dione(CNQX)来观察低温对海马脑片OGD损伤保护作用的突触后受体机制。③观察OGD1h后海马CA1区锥体细胞超微结构的变化及低温对其的影响。结果:①OGD可以使海马脑片OPS迅速降低并很快消失,14min后复氧供糖OPS极少恢复。低温(32℃、25℃)能使OPS消失时间明显延长,复氧供糖后OPS恢复良好。25℃其作用优于32℃。②2mmol/L Glu使海马脑片OPS迅速消失,洗出后难以恢复。低温(32℃、25℃)能显著改善去Glu1h后OPS的恢复。ACSF中加入BMI+CNQX和BMI+AP5均对25℃低温处理28min的脑保护作用没有影响。③OGD1h后CA1区锥体细胞水肿严重,胞浆内细胞器变性坏死脱失,线粒体肿胀,脊呈空泡状。低温(25℃)组细胞核膜规则,线粒体轻度肿胀。结论:低温有显?更多还原

【Abstract】 Aim: To investigate the relation between Glu R and the protective effect of hypothermia on oxygen and glucose deprivation(OGD) injury in hippocampal slices of rat. Methods: ①We had established OGD injury model in rat hippocampal slices. The changes of orthodromic population spike(OPS) during OGD and after administration of hypothermia(32℃,25℃) were observed. ②We had established Glu excitatory toxicity injury model in rat hippocampal slices. The changes of OPS after exposure to Glu and the effect of hypothermia(32℃,25℃) against the Glu excitatory toxicity injury were observed. The non NMDA receptor mediated excitatory postsynaptic potentials(EPSP) in the CA1 area were recorded via adding the GABA R specific agonists bicuculline(BMI) and NMDA R agonists D ( ) 2 Amino 5 phosphonopentanoic Acid(AP5) in normal artificial cerebrospinal fluid(nACSF), the NMDA receptor mediated EPSP were recorded via adding the BMI and non NMDA R agonists 6,7 Dinitroquinoxaline 2,3(1H,4H) dione(CNQX) in nACSF. The variety of the changes of OPS during OGD14min in nACSF groups and added BMI compounded AP5 or BMI compoun ded CNQX ACSF groups were observed after administration of 25℃ hypothermia 28 min. ③The changes of ultrastructure of CA1 area after OGD 1 h and the effect of hypothermia(25℃) on it were observed. Results: ①OPS reduced and abolished quickly during OGD14min, and the recovery amplitude of OPS was very low after rexygenation/glucose 1 h. While the time of OPS abolishing significantly elongated and the recovery of OPS was higher in hypothermia(32℃,25℃) groups. The effect in groups 25℃ was more significant than those in groups 32℃.②In control groups, Glu(2 mmol/L, 14 min) decreased the amplitude of OPS, after the end of Glu exposure the recovery amplitude of OPS was very low. After administration of hypothemia(32℃,25℃), the recovery amplitude and rate of OPS were significantly higher than those in the control groups, while the antagonism on Glu excitatory toxicity injury in H 25℃ was more significant than those in H 32℃. The changes of OPS during OGD 14 min were no distinct difference in nACSF groups and added BMI(50 μmol/L) compounded AP5(20 μmol/L) or BMI(50 μmol/L) compounded CNQX(100 μmol/L) ACSF groups. The protection of hypothermia(25℃) could not be cancelled by added AP5 compounded BMI or BMI compounded CNQX in nACSF. ③After OGD(14 min) 1 h, the nuclear membrane of pyramidal cells in CA1 area was irregular, nucleus were homogenized, the organelle in the cytoplasm was degenerate, even more to necrosis or loss, mitochondrion swelled, ridge was vacuoles. In H 25℃ the nuclear membrane was regular, mitochomdrion swelled only lightly. Small chromatin gathered to edge. Conclusion: Hypothermia shows the protective effects of against OGD injury in hippocampal slices. The mechanism is related to the antagonism of Glu excitory toxicity and maintenance the ATP level in cells, and the antagonism perhaps is mediated by NMDA R and non NMDA R.更多还原