电针对局灶性脑缺血大鼠缺血灶周围区星形胶质细胞谷氨酸转运体的影响

Effect of Eletroacupuncture on EAAT1 and EAAT2 of Astrocyte in the Marginal Zone of Cerebral Ischemia in Rats

目的:观察电针对不同时间段局灶性脑缺血模型大鼠缺血灶周围区星形胶质细胞谷氨酸转运体兴奋性氨基转运体1(excitatory amino acid transporters 1,EAAT1)、兴奋性氨基酸转运体2(excitatory amino acid transporters 2,EAAT2)的影响。方法:90只Wistar大鼠随机分为假手术组、模型组和电针组,每组又分为l hl、d3、d、7 d和21 d 5个时间段小组。采用热凝闭大脑中动脉复制局灶性脑缺血模型,电针组给予电针"百会"、"大椎"穴治疗。每个时间段后分别取材,采用免疫组织化学法检测各组大鼠脑缺血灶周围区谷氨酸转运体EAAT1、EAAT2的表达。结果:模型组EAAT1的表达在1,3 d时较假手术组显著升高(P<0.05,P<0.01),随后持续下降;7,21 d时仍显著高于同时段假手术组(P<0.05,P<0.01)。电针组EAAT1的表达于1 h即开始增加,与假手术组比较,差异有显著性(P<0.05);在1,3,7 d及21 d时,电针组EAAT1的变化趋势与模型组基本相仿,但均显著高于同时段模型组的表达(P<0.01)。模型组EAAT2的表达在1 h、1d3、d及7 d时均高于同时段的假手术组(P<0.01),电针组EAAT2的变化趋势与模型组基本一致,但在21 d时仍显著高于假手术组(P<0.01),且在各时段均高于模型组的表达(P<0.05,P<0.01)。结论:电针可以提高大鼠脑缺血灶周围区星形胶质细胞谷氨酸转运体EAAT1、EAAT2的表达,从而增强星形胶质细胞灭活谷氨酸的能力。

Objective.. To observe the effect of electroacupuncture （EA） on excitatory amino acid transporters 1 （EAAT1） and excitatory amino acid transporters 2 （EAAT2） of astrocyte in rat model of focal cerebral ischemia at different times. Methods. Ninety Wistar rats were randomized into sham group, model group and EA group. Each group was observed at 1 hour, 1 day, 3 days, 7 days and 21 days after cerebral ischemia. Heat-coagulation-induced occlusion of the middle cerebral artery was performed to establish the model of focal cerebral ischemia. EA was applied to Baihui （GV20） and Dazhui （GV14） in EA group. EAAT1 and EAAT2 expression of the marginal zone of cerebral ischemia was assayed with immunohisto- chemical method in different groups. Results. In comparison with that in sham group, Optical Density （OD） values of EAAT1 in model group increased obviously at day 1, day 3, day 7 and day 21（P（0.05, P〈0.01） ,while compared with that in sham group, the OD value of EAAT1 in EA group increased significantly at 1 hour（P（0.05）, and the change of EAAT1 expression in EA group was similar to that in model group at day 1, day 3, day 7 and day 21, but OD values of EAAT1 in EA group were significantly higher than those in model group （P〈0.01）. In comparison with those in sham group, OD values of EAAT2 in model group increased obviously at 1 hour ,day 1, day 3 and day 7 （P〈0. 01）, and the change of EAAT2 expression in EA group was similar to that in model group, however, in comparison with that in sham group, the OD values of EAAT2 in EA group still increased significantly at day 21 （P〈0.01）, and OD values of EAAT2 in EA group were significantly higher than those in model group （P〈0. 05, P〈0.01）. Conclusion： EA can improve the expression of EAAT1 and EAAT2 of amrocyte in the marginal zone of cerebral ischemia in rats, which strengthen the ability of transportation of glutamic acid by astrocyte.