微管相关蛋白tau在不同年龄大鼠海马内的定位分布特点

Distributional characteristics of microtubule associated protein tau in the hippocampus of different aged rats

目的检测微管相关蛋白tau和Ser396/404位点磷酸化tau在胚胎期大鼠和出生后直至成熟期大鼠海马内的表达及变化规律,浅析与神经细胞分裂和分化的关系。方法用免疫组织化学SABC法显示孕18d、出生后1d、1w、2w、2m的大鼠脑冠状切面总tau(R134d)、Ser396/404位点磷酸化tau(PHF-1)的表达。结果①胚胎期大鼠海马CA区的锥体细胞数量明显多于出生后,随着脑的发育,锥体细胞层的神经细胞数量逐渐下降;②孕18d大鼠海马内有丰富的总tau和PHF-1tau的表达,并且海马内各区的阳性物质表达均匀,生后1d和1w两种物质表达仍然很强,阳性产物主要分布在海马CA1和CA2区以锥体细胞轴突为主要成分的始层,在锥体细胞树突集中的分子层和胞核内也有少量分布,而在生后2w和2m大鼠海马内各区均未见密集的阳性产物表达。结论不同年龄大鼠海马内总tau和PHF-1tau的表达和分布变化可能与神经系统发育过程中细胞的分裂和分化有关。

Objective To detect the expression and distribution of microtubule associated protein tau and phosphorylated tau at Ser396/404 （PHF-1） sites in different aged rats＇hippocampus, and elementary analyze the relationship between the levels of total tau and phosphorylated tau at Ser396/404, andneuronal cell division and differentiation during the brain development. Methods To present the distribution of total tau andPHF-1 phosphorylated tau distribution in embryonic 18 day, postnatal 1 day, 1 week, 2 weeks, and 2 months rats＇ hippocampus with immunohistochemistry SABC methods. Results （~ CA area of em- bryonic hippocampus contains much more pyramidal cells than those of postnatal rats. The amopnt of hip- pocampal neurons in CA area decreased gradually with the development of brain; O total tau and PHF-1 phosphorylated tau are high expressed in the hippocampus of embryo 18 day rats with well-distribution in each area. They are also high expressed in the postnatal 1 day and 1 week rats＇ hippocampus. The positive substance is mainly located in the original layer constituted with axons of pyramidal cells, and low ex pressed in the molecular layer with dendrites and nuclei of pyramidal cells. But in the postnatal 2 weeks and 2 months rat＇s hippocampus, almost no obvious positive substance is expressed. Conclusion The char acteristic and change rule of tau and PHF-1 phosphorylated tau expression and distribution in hippocampus maybe have special relationship with the cell division and differentiation with neural system development.