升麻苷H-1对脑缺血大鼠纹状体氨基酸类神经递质含量的影响

 目的:研究脑缺血大鼠脑纹状体区域细胞外液中氨基酸类神经递质的表达变化,以探讨升麻苷H-1神经保护作用的机制。方法:SD 大鼠随机分为假手术组、脑缺血组、升麻苷H-1高、中、低剂量组和金纳多组。用线栓法造成右侧大脑中动脉闭塞(MCAO),建立局灶脑缺血模型,假手术组和脑缺血组分别给予生理盐水腹腔注射,升麻苷H-1高、中、低剂量组和金纳多组分别给予不同剂量的药物腹腔注射,每天1 次,连续7 d。采用脑微透析技术在大鼠脑纹状体区域内进行微透析活体采样,将微透析液注入高效液相-电化学检测器,检测样品中谷氨酸(Glu)、天门冬氨酸(Asp)、甘氨酸(Gly)和γ-氨基丁酸(GABA)的含量。结果:与假手术组相比,脑缺血组的兴奋性氨基酸Glu和Asp在脑缺血后2 h浓度升高(P<0.05)。升麻苷H-1高剂量组、金纳多组分别与脑缺血组相比,Glu和Asp在脑缺血后2 h显著降低(P<0.05);升麻苷H-1低、中剂量组分别与脑缺血组相比,Glu和Asp在脑缺血后2 h 没有显著降低(P>0.05)。与假手术组相比,脑缺血组的抑制性氨基酸神经递质GABA 和Gly在脑缺血后3 h浓度降低(P<0.05)。升麻苷H-1高剂量组、金纳多组分别与脑缺血组相比,GABA 和Gly在脑缺血后3 h显著升高(P<0.05);升麻苷H-1低、中剂量组分别与脑缺血组相比,GABA 和Gly在脑缺血后3 h 没有显著升高。结论:升麻苷H-1可以抑制脑缺血时兴奋性氨基酸的过度释放,并增加抑制性氨基酸的浓度。升麻苷H-1不仅能透过血脑屏障,同时可调节脑缺血兴奋性氨基酸神经递质的功能紊乱,可能对缺血脑组织神经元有一定的保护作用。

Effect of cimicifugoside H-1 on amino acid neurotransmitters in striatum of rats with cerebral ischemia

AIM: To study the neuroprotective effect of cimicifugoside H-1 and to explore the mechanism involved by determining the variation of amino acid neurotransmitters in extracellular fluid in the striatum of rats with cerebral ischemia. METHODS: The rats were randomly divided into sham-operated, cerebral ischemia, high-, middle- and low-dose cimicifugoside H-1, and ginkgo groups. Focal cerebral ischemia model was established by middle cerebral artery occlusion (MCAO) with sutures. Normal saline was intraperitoneally injected into the rats in sham-operated group and cerebral ischemia group, while ginkgo and different doses of cimicifugoside H-1 were injected into the rats in ginkgo group and high-, middle- and low-dose cimicifugoside H-1 groups, respectively, once a day for 7 d. The striatal fluids were gained in vivo by brain microdialysis. The contents of aspartic acid, glutamic acid, glycine and γ-aminobutyric acid were tested by high-performance liquid chromatography electrochemical detector system. RESULTS: Compared with sham-operated group, the contents of excitatory amino acids (aspartic acid and glutamic acid) were significantly increased 2 h after cerebral ischemia (P<0.05). Compared with cerebral ischemia group, the contents of aspartic acid and glutamic acid were significantly decreased 2 h after cerebral ischemia in high-dose cimicifugoside H-1 and ginkgo groups (P<0.05). Compared with cerebral ischemia group, the contents of aspartic acid and glutamic acid did not show significant decrease 2 h after cerebral ischemia in middle- and low-dose cimicifugoside H-1 groups. Compared with sham-operated group, the contents of inhibitory amino acid (γ-aminobutyric acid and glycine) were significantly decreased 3 h after cerebral ischemia in cerebral ischemia group (P<0.05). Compared with cerebral ischemia group, the contents of γ-aminobutyric acid and glycine were significantly increased 3 h after cerebral ischemia in high-dose cimicifugoside H-1 and ginkgo groups (P<0.05). Compared with cerebral ischemia group, the contents of γ-aminobutyric acid and glycine did not show significant decrease 3 h after cerebral ischemia in middle- and low-dose cimicifugoside H-1 groups. CONCLUSION: Cimicifugoside H-1 restrains the excessive releases of excitatory amino acids and increases the contents of inhibitory amino acids during cerebral ischemia. It doesn't only penetrate through the blood brain barrier, but also regulates the disorder of excitatory amino acid during cerebral ischemia, thus showing the protective function to cerebral neuron during cerebral ischemia.