葛根素对脑缺血再灌注损伤大鼠纹状体氨基酸水平的影响  

Effects of Puerarin on Excitatory Amino Acid Levels in Cerebral Ischemic Striatum of Rat

作　　者：徐晓虹[1] 郑筱祥[2] 李惠[2] 

机构地区：[1]浙江师范大学化学与生命科学学院,浙江金华321004 [2]浙江大学生物医学工程教育部重点实验室,杭州310027

出　　处：《中国药学杂志》2008年第9期675-679,共5页Chinese Pharmaceutical Journal

基　　金：浙江省自然科学基金(M303042)

摘　　要：目的研究葛根素对脑缺血再灌注损伤大鼠纹状体氨基酸水平的影响。方法大脑中动脉栓塞(MCAO)60min建立大鼠局部脑缺血模型。给药组在缺血前30min和再灌注开始时分别腹腔注射Pur(50,100mg·kg-1,ip)。用脑微透析仪收集缺血前后和再灌注过程纹状体的细胞外液,高效液相色谱分析其兴奋性和抑制性氨基酸水平;缺血再灌注24h取脑用TTC染色法测算脑梗死体积和水肿率。用流式细胞仪结合Annexin-V荧光标记法检测Pur(40,100μmol·L-1)对体外培养海马神经细胞谷氨酸(0.5mmol·L-1)诱导细胞凋亡的保护作用。结果缺血开始后,纹状体的天门冬氨酸(Asp)、谷氨酸(Glu)、γ-氨基丁酸(GABA)和牛磺酸(Tau)水平快速升高,最高时分别达缺血前的8.92,14.15,9.07和4.84倍。再灌注开始后,氨基酸水平迅速下降,120min后接近正常。100mg·kg-1Pur在减小脑梗死体积和脑水肿的同时,显著降低脑缺血过程纹状体氨基酸水平,其最高值分别比缺血组降低35.7%(Asp)、43.2%(Glu)、28.5%(GABA)和31.8%(Tau)(P<0.01);Glu/GABA比值明显低于缺血大鼠。流式细胞检测结果显示,100μmol·L-1Pur明显抑制谷氨酸兴奋毒作用,分别使海马神经细胞的凋亡率和坏死率降低33.1%和35%(P<0.01)。结论Pur可有效抑制脑缺血诱导的细胞外氨基酸水平升高和谷氨酸兴奋毒作用,该机制可能与Pur的抗脑缺血作用有关。OBJECTIVE To investigate the effects of puerarin （Pur） on the excitatory amino acid levels in cerebral ischemic striatum of Rat. METHODS Male SD rats were subjected to 60 min of transient middle cerebral artery occlusion （MCAO） followed by reperfusion. Pur （50, 100 mg · kg^-1 , ip） was administrated 30 min before MCAO and at the start of reperfusion. The infarct rate and edema rate were determined on TTC-stained coronal sections. The extracellular levels of amino acid transmitters were monitored in the striatum of the ischemic/reperfused rats using microdialysis technique in vivo. The effects of Pur against glutamate-induced apoptosis and necrosis were estimated in the hippocampal cultures by means of flow cytometric analysis of Annexin-Ⅴ and PI labeling cells. RESULTS MCAO resulted in a rapid increase in the striatum dialysate levels of amino acids, and the maximal fold increases were ： Asp 8.92, Glu 14. 15, GABA 9. 07 and Tau 4. 84. The levels of these amino acids subsequently declined towards their pre-ischemic values during the 120 min reperfusion period. Accompanyed by decreases of infarct size and edema volume, and improvment of neurological functions, Pur （ 100 mg · kg^-1 ） markedly attenuated the ischemia-induced increases of the extracellular levels of amino acids in striatum; and the maximal fold increases reduced by 35.7 % （ Asp）, 43.2% （ Glu）, 28.5 % （ GABA ）, and 31.8 % （Tau） （ P 〈 0. 01 ） respectively as compared with the vehicle-treated MCAO rats. Futhermore, apoptosis and necrosis induced by Glu in cultured hippocampal neurons were significantly reduced by 33. 1% and 35 % （ P 〈 0. 01 ） after treatment with 100 μmol · L^-1 Pur. CONCLUSION Treatment with Pur significantly depressed ischemia-induced efflux of amino acids, in particular, excitotoxicity in the striatum, a mechanism that may participate in the neuroprotective effect on cellular survival.

关 键 词：葛根素 脑缺血 脑微透析 氨基酸递质 

分 类 号：R965[医药卫生—药理学]