大鼠海马CA1区星形胶质细胞对突触的影响

Effect of Astrocytes on Synapses in the CA1 Region of Hippocampus

目的:研究发育期大鼠海马CA1区星形胶质细胞与突触数量和成熟度的关系.方法:取健康初生(＜24 h)、幼年(28～30 d)和成年大鼠(90～100 d)各20只,分别用免疫组织化学方法和电子显微镜观察海马CA1区星形胶质细胞数量和突触超微形态结构特点,用高压液相色谱法检测其胆固醇含量.结果:在各组大鼠海马CA1区,初生组存在大量神经元,但星形胶质细胞少,末见突触结构;幼鼠组可见星形胶质细胞和不成熟的突触结构;成鼠组可见大量星形胶质细胞和远比幼鼠丰富的成熟突触结构(P<0.01);胆固醇含量为初生组(2.92±0.03) g·kg-1, 幼鼠组(11.20±3.41) g·kg-1,成鼠组(12.91±1.25)g·kg-1, 相互间差别均有显著性意义(P<0.01).结论:大鼠发育过程中海马CA1区星形胶质细胞数量可能影响突触数量和成熟度, 此影响可能与胆固醇有关.

Objective： To investigate the relation between the astrocyte and the synaptic number or maturity in the hippocampal CA1 region of growth rats. Methods： Experiments were performed on the group of the new born （〈24 h）, the juvenile （28～30 d） and the adult rats （90～100 d）, with 20 rats in each group. The comparison of the growth of astrocytes had been carried out in the CA1 region of rat hippocampus immunohistochemically by means of specific antiserum of glial fibrillary acidic protein （GFAP）. And the synaptic uhrastructures were observed under electron microscope. The cholesterol in them was individually determined by high performance liquid chromatography. Results： A lot of neurons were observed in the hippocampal CA1 region of brain slices of the new-born rats, while the expression of GFAP were much rare and the synaptic uhra- structures could not be found. In the juveniles, a few astrocytes and some unmature synapses were found, less than those in adult rats （P〈0.01）. The cholesterol concentration in eachofthe three samples was （2.92±0.03）, （11.20±3.41） and （12.91±1.25） mg·g^-1 respectively and the difference was significant （P〈0.01）. Conclusion： The astrocyte may be closely related to the synaptic number and structural maturity, which may be associated with the cholesterol, in the hippocampi of growth rats.