Hu Bo, Sun Shenggang, Mei Guangwu, Chen Liangyi, Tong E'tang
Neurology Department, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
Chin Med J (Engl). 2002 Sep;115(9):1316-20.
To study the effect of Ginkgo biloba extract on rats during ischemia/reperfusion and its influence on intracellular calcium in hippocampal neurons.
Model of intraluminal occlusion of the middle cerebral artery (MCAO) was used to prepare the ischemia/reperfusion cortex tissue. Concentration of MDA was determined by measuring thiobarbituric acid-reactive substance. GSH-PX was quantified using the thiobarbituric acid (TBA) technique. SOD was assayed througha xanthine method. Endogenous amino acids were quantified by high performance liquid chromatographic (HPLC) analysis. Primary culturs of hippocampal neurons were prepared for a free intracellular calcium ([Ca(2+)]I) assay by Fura-2 based single cell microfluoremetric technique.
Comparing control and treatment groups, the concentration of SOD and GSH-PX were higher, whereas that of MDA was much lower; the concentration of glutamate and aspartate decreased and that of GABA increased markedly at all time point (P < 0.01), Gly also decreased at some time points (P < 0.05). The differences were significant between the groups of 10 mg/kg, 15 mg/kg and the groups of 5 mg/kg. When 1 x 10(-5) mol/L glutamate was applied with 25 micro g/ml ginkgo biloba extract to cultured neurons, the increase in [Ca(2+)]I was lower than that caused by applying glutamate alone. Its peak value was much lower and increased phase was longer, its declining phase was shorter. After returning to baseline, the application of 1 x 10(-5) mol/L glutamate could induce the reaction to recover.
Ginkgo biloba extract could protect damaged neurons by keeping the balance of inhibitory/excitatory aminoacids, enhancing the free radical scavengers system, and inhibiting the effect of glutamate on [Ca(2+)]I.
研究银杏叶提取物对大鼠缺血/再灌注损伤的影响及其对海马神经元细胞内钙的作用。
采用大脑中动脉（MCAO）腔内闭塞模型制备缺血/再灌注皮层组织。通过测定硫代巴比妥酸反应物质来确定丙二醛（MDA）的浓度。采用硫代巴比妥酸（TBA）技术对谷胱甘肽过氧化物酶（GSH-PX）进行定量分析。通过黄嘌呤法测定超氧化物歧化酶（SOD）活性。采用高效液相色谱（HPLC）分析法对内源性氨基酸进行定量分析。利用基于Fura-2的单细胞显微荧光测定技术制备海马神经元原代培养物，用于细胞内游离钙（[Ca(2+)]I）检测。
与对照组相比，治疗组SOD和GSH-PX浓度升高，MDA浓度显著降低；各时间点谷氨酸和天冬氨酸浓度降低，γ-氨基丁酸（GABA）浓度显著升高（P < 0.01），甘氨酸（Gly）在部分时间点也降低（P < 0.05）。10 mg/kg、15 mg/kg组与5 mg/kg组之间差异有统计学意义。当向培养的神经元中加入1×10(-5) mol/L谷氨酸和25 μg/ml银杏叶提取物时，[Ca(2+)]I的升高低于单独加入谷氨酸时。其峰值更低，上升期更长，下降期更短。恢复到基线后，加入1×10(-5) mol/L谷氨酸可诱导反应恢复。
银杏叶提取物可通过维持抑制性/兴奋性氨基酸平衡、增强自由基清除系统及抑制谷氨酸对[Ca(2+)]I的作用来保护受损神经元。
