大鼠星形胶质细胞在突触形成中的作用及机制  

THE EFFECT AND MECHANISM OF ASTROCYTE ON SYNAPTIC FORMATION IN RATS

作　　者：胡荣[1] 吴喜贵[1] 杨忠[1] 魏璐[1] 蔡文琴[1] 

机构地区：[1]第三军医大学神经生物学教研室重庆市神经科学研究所,重庆400038

出　　处：《解剖学报》2005年第3期225-230,共6页Acta Anatomica Sinica

基　　金：国家自然科学基金资助(30270452)

摘　　要：目的观察星形胶质细胞(AST)分泌雌激素的规律,研究AST对大脑皮层神经元突触形成的影响及可能的分子机制。方法取新生大鼠大脑皮层进行AST原代及传代培养,分别于传代培养的第0d、7d、14d、21d进行细胞计数,同时用ELISA方法测定AST条件培养液(ACM)中雌二醇(E2)的浓度。以新生大鼠皮层神经元纯培养为模型,实验分成6组:神经元纯培养组;ACM培养组;AST和神经元混合培养组;雌激素培养组;ACM+Tamoxifen(雌激素受体阻断剂)培养组;Tamoxifen培养组。应用免疫荧光技术和突触计数方法观察各组突触形成数量的差别。结果AST数量分别为1×104/ml、1.1×106/ml、1.4×106/ml、1.5×106/m1;ACM中雌二醇浓度分别为(ng L):0、117±22、266±22、252±27。第0d培养液中未检测出雌二醇,随着培养时间的延长雌激素浓度迅速增加,14d左右达高峰,以后逐渐降低,但21d时培养液中雌二醇仍保持较高浓度。各实验组突触荧光颗粒数分别为(个/细胞,培养第9d):14±3;79±5;83±8;80±6;32±3;29±3。显示ACM能增加培养神经元突触形成的数目近6倍,外源性雌激素可基本模拟ACM的效应。Tamoxifen能阻断ACM促突触形成效应的75%左右。结论体外培养新生大鼠大脑皮层AST能合成并分泌雌激素,分泌的雌激素可能参与了胶质细胞调节神经元突触形成的过程,Objective To study the effect of astrocyte on synapse formation and the molecular mechanism. Methods Cortical astrocytes were isolated and purified from neonatal rats.On the 2h,7th day,14th day and 21th day after passage,we counted the number of astrocytes and the culture medium(astrocyte-conditioned medium,ACM)was harvested to measure the concentration of estrogen(E 2)by using ELISA techniques.Based on the model of pure culures of neonatal cortical neurons,the experimental groups were designed as follows:1.pure neuron cultures(group N);2.ACM cultures(group A);3.mixed cultures(group M);4.E 2 cultures(group E 2);5.ACM+Tamoxifen(estrogen receptor antagonist)cultures(group A+T);6.Tamoxifen cultures(group T).Then synaptic puncta in every group was stained and counted through immunofluorescence,and we also compared the differences in puncta number among those six groups(at 9th day in culture,number/per neuron). Results The numbers of astrocytes were:1×10 4/ml, 1.1×10 6/ml, 1.4×10 6/ml, 1.5×10 6/ml; The concentrations of E 2 were:(ng/L):0, 117±22, 266±22,252±27 respectively.No estrogen was detected in the primary culture medium.The concenteration of estrogen increased in correspondence with the culturing days and reached the peak around at the 14th day, then decreased gradually but kept at a certain high level,and the numbers of synaptic puncta of per neuron in group N,A,M,E 2,A+T,T were:14±3;79±5;83±8;80±6;32±3;29±3 respectively.The treatment of pure neuron culture with ACM increased the number of synapses on per neuron by up to 6 fold by comparison with pure neuronal culture.Exogenic estradiol added into pure neurons can mimick the effect of the ACM.Tamoxifen which is antagonist of estrogen receptor could decrease the effect of ACM by 75%.Conclusion The astrocytes of neonatal rat cortex do secrete E 2.Astrocyte-derived estrogen may be the molecule regulating the synaptic formation through estrogen receptors.

关 键 词：星形胶质细胞 神经元 突触形成 雌激素 雌激素受体 免疫荧光 细胞培养 大鼠 

分 类 号：R322.81[医药卫生—人体解剖和组织胚胎学] R329.2[医药卫生—基础医学]