突触结合蛋白Ⅰ和Ⅳ在小鼠背海马表达的区域差异及年龄相关性变化

Different distributions and age-related changes of synaptotagmin Ⅰ and Ⅳ in dorsal hippocampus of mice

目的：探讨昆明小鼠背海马突触前囊泡蛋白（Syt）Ⅰ和Ⅳ的分布差异及其年龄相关性变化.方法：选取3个年龄段昆明小鼠22月龄17只、11月龄22只和6月龄28只作为研究对象,采用免疫组织化学技术检测其背海马Syt Ⅰ和Syt Ⅳ含量.结果：SytⅠ与Syt Ⅳ在不同年龄组小鼠背海马锥体细胞和颗粒细胞中均有表达,其中SytⅠ在CA3区透明层和齿状回（DG）门区呈高表达,而Syt Ⅳ在锥体细胞和颗粒细胞胞膜呈高表达.22月龄鼠在海马CA1、 CA3和DG中Syt Ⅰ的相对含量高于11月龄和6月龄鼠,而Syt Ⅳ的相对含量低于6月龄鼠.结论：相对于中、青年鼠而言,老年昆明小鼠背海马Syt Ⅰ水平升高而Syt Ⅳ水平降低;Syt Ⅰ的优势表达可能在苔藓纤维及其与CA3区锥体细胞顶树突形成的轴-树或树-树型突触,Syt Ⅳ的优势表达可能在锥体细胞和颗粒细胞的轴-体或树-体型突触.

Objective： To explore different distributions and age-related changes of synaptotagmin （Syt） Ⅰ and Syt Ⅳ in dorsal hippocampus of mice. Methods： Three groups at different ages of Kunming mice （aged at 22, 11 and 6 months, respectively） were used to made into tissue microarrays and the expressions of Syt Ⅰ and Syt Ⅳ were detected by the immunohistochemistry method （S-P method）. Results： The expressions of Syt I and Syt Ⅳ were observed in the both pyramidal and granular cells in the hippocampus of the Kunming mice at different ages. However, the Syt expression was higher in the apical dendrite in CA3 and the mossy fiber in dentate gyrus （DG） and the Syt Ⅳexpression was higher in the membranes of pyramidal and granular cells compared with other subareas. The relative Syt Ⅰ amount in CA1, CA3 and DG of the dorsal hippocampus in the 22-month-old mice was significantly higher than that in the middle-aged and young mice, and the relative Syt Ⅳ amount in the 22-month-old mice was significantly lower than that in the young mice. Conclusion： The hippocampal Syt Ⅰ level was increased and Syt Ⅳ was decreased with aging. It is possible that the Syt Ⅰ mainly expressed in the the mossy fiber and the axo-dendritic synapse and the Syt Ⅳ mainly expressed in the axo and dendrcrsomatic synapses in pyramidal and granular cells in the hippocampus.