电针对大鼠脑缺血灶周围区少突胶质细胞超微结构及蛋白表达的影响

目的:观察电针对脑缺血大鼠缺血灶周围区皮层不同时间段少突胶质细胞反应性变化的影响,进一步揭示针刺治疗脑缺血疾病的可能作用机制。方法:雄性SD大鼠90只,随机分为假手术组、模型组和电针组,各组又分为术后1h、1d、3d、7d及21d组5个时间段亚组,6只/亚组。采用改良线栓法阻塞大脑中动脉复制局灶性脑缺血模型。电针组电针"百会""大椎"穴,留针30min,1次/d。用透射电镜观察缺血灶周围区皮层的少突胶质细胞超微结构。用蛋白标记物A2B5、O4、CNPase分别标记前体少突胶质细胞、未成熟少突胶质细胞、成熟少突胶质细胞,免疫组化法观测各组大鼠蛋白表达变化。结果:模型组少突胶质细胞在缺血性脑损伤后肿胀、增多,电针组的少突胶质细胞肿胀程度较模型组减轻并促进少突胶质细胞的增生。模型组A2B5的表达在术后3d、7d时明显高于假手术组(P0.05),在7d时表达最强,而电针组A2B5的表达在术后1h、3d、7d、21d时均明显高于模型组(P0.01,P0.05);模型组O4的表达在术后1h、1d、3d、7d时均明显低于假手术组(P0.01),在3d时表达最少,而电针组O4的表达在1d、3d、7d、21d时均高于模型组(P0.05,P0.01);模型组CNPase的表达在术后3d、7d时明显高于假手术组(P0.05),而电针组CNPase的表达在术后1d、3d、7d、21d时均明显高于模型组(P0.01,P0.05)。结论:电针可能通过减轻脑缺血引起的少突胶质细胞结构性损伤及促进A2B5、O4、CNPase表达,发挥胶质细胞对神经元的保护效应。

Effect of Electroacupuncture on Ultrastructure of Oligodendrocytes and Expression of the Related Marker Proteins in the Marginal Zone of Cerebral Ischemia Locus in Rats

Objective To observe the effect of electroacupuncture(EA)on changes of ultrastructure of oligodendrocytes in the marginal zone of the cerebral ischemia(CI)locus in rats with cerebral infarction so as to reveal its mechanism underlying improving ischemic cerebral diseases.Methods Ninety male SD rats were randomized into sham operation,model and electroacupuncture(EA)groups which were further divided into five subgroups:1h,1d,3d,7d,and 21 dafter CI(n=6in each subgroup).The CI model was established by occlusion of the middle cerebral artery.EA(1-3mA)was applied to"Baihui"(GV20)and"Dazhui"(GV 14)for 30 min,once a day for 1h,1d,3d,7dand 21 d,respectively.The ultrastructural changes of oligodendrocytes in the marginal zone of the ischemic cerebral tissue were observed by transmission electron microscope.The immunoactivity levels of A2B5,O4 and 2',3'-cyclic-nucleotide 3'-phosphodiesterase(CNPase)for labeling the oligodendrocyte precursor cells,immature oligodendrocytes,and mature oligodendrocytes respectively were detected by immunohistochemistry.Results The oligodendrocytes were swelling in structure and increased in number after cerebral ischemia.Compared with the model group,the degree of swelling of oligodendrocytes was obviously decreased and new oligodendrocyte proliferation was found in the EA group.In comparison with the sham group,the immunoactivity levels of cerebral A2B5 and CNPase proteins on day 3and7 were significantly higher in the model group(P<0.05),while those of O4 on day 1,3,7and 21 were obviously lower in the model group(P<0.01).Following EA intervention,the immunoactivity levels of cerebral A2B5,O4 and CNPase proteins were significantly up-regulated in the EA group in comparison with the model group(P<0.01,P<0.05).Conclusion EA intervention may reduce the structural damage of oligodendrocytes in CI rats,which may be associated with its effects in promoting the expression of cerebral A2B5,O4 and CNPase proteins,suggesting an involvement of glial cells in the protective effect of EA.