黄芪多糖对缺血缺氧脑损伤大鼠脑组织Ca^(2+)和兴奋性氨基酸的影响

Effects of Astragali polysaccharides on levels of calcium ion and excitatory amino acids for rats with hypoxia-ischemia cerebral damage

目的:探讨黄芪多糖对缺血缺氧脑损伤大鼠脑组织中Ca^(2+)和兴奋性氨基酸水平的影响。方法:60只大鼠随机分成3组:假手术组、模型组、黄芪多糖组,每组20只。采用改良Longa线栓法制备大鼠中动脉栓塞(MCAO)模型。黄芪多糖组于脑缺血前30 min及术后8 h按1g·kg^(-1)分别腹腔注射给药1次,模型组和假手术组于同时间腹腔注射等容量生理氯化钠溶液。3组均于造模24 h后断头取血2 mL,分离血清,并取全脑,测脑组织的Ca^(2+)含量、脑组织和血清中谷氨酸(Glu)和天门冬氨酸(Asp)的含量。结果:模型组脑组织Ca^(2+)、脑组织和血清Glu和Asp含量均明显高于假手术组(P＜0．01),黄芪多糖组这些指标的变化则显著低于模型组(P＜0．01或P＜0．05)。结论:黄芪多糖对缺血缺氧脑损伤大鼠具有脑保护作用,其机制可能与降低脑内Ca^(2+)和兴奋性氨基酸的含量有关。

Objective： To assess the effects of Astragalus polysaccharides （APS） on levels of calcium ion and excitatory amino acids （EAA） for rats with hypoxia-ischemia cerebral damage. Methods： Sixty rats were randomly assigned one of three study groups： sham operation, model control and APS treatment. The middle cerebral artery occlusion model in rats was established with modified Longa＇s method, and the rats were abdominally injected with APS 1 g-kg-~ both 30 minutes ahead of the cerebral ischemia and 8 hours after the cerebral damage. The rats in sham operation and model control were abdominally administrated with same dose of saline solutions. All rats were in euthanasia in 24 hours after the ischemia damage to collect serum samples （2mL） and whole cerebral tissues. The concentrations of calcium ion, aspartate （Asp） and glutamate （Glu） in the cerebral tissues and/or serum samples were measured. Results： The concentrations of calcium ions, Glu and Asp were significantly higher in the model control than in the sham operation （P 〈 0.01 ）. APS-treated rats significantly experienced less levels of calcium ion, Glu and Asp than the model control rats（P 〈0.01 or P 〈0. 05）. Conclusion： APS protect rats＇ cerebral tissues from hypoxia-ischemic damage by reducing the levels of calcium and EAA.