中文摘要：

目的：探讨突触后密度蛋白-95（PSD-95）在大鼠脊髓发育过程中的表达变化以及细胞定位。方法：采用实时定量PCR（Real-Time PCR）和Western blot测定发育不同时期PSD-95 mRNA及蛋白水平的表达变化。采用免疫荧光染色显示PSD-95在发育脊髓中的细胞定位。结果：大鼠脊髓发育过程中PSD-95 mRNA及其蛋白水平从生后1d开始逐渐升高,在生后1周达高锋,成年后维持在一定的生理水平。免疫荧光双标证实PSD-95在生后发育早期主要定位于脊髓灰质,与神经元的标记物NeuN和突触的标记物synapsin存在共定位;成年后广泛分布于脊髓前角、后角以及白质,分别与NeuN和synapsin以及小胶质细胞的标记物OX-42共定位。结论：大鼠脊髓发育过程中PSD-95在基因和蛋白水平呈现明显的时相变化,在生后发育早期主要表达在前角运动神经元和后角感觉神经元,提示PSD-95参与了神经元的发育和成熟。

英文摘要：

Objective： To study the expression and localization of postsynaptic density protein-95 （PSD-95） in the developing spinal cord. Methods： Real-Time PCR and Western blot were used to detect the different expression of mRNA and protein levels of PSD-95 respectively. Immunofluorescence staining was used to observe the distribution of PSD-95 in the developing spinal cord. Results： During the development of spinal cord, the expression of mRNA and protein of PSD-95 began to increase at postnatal day 1, peaked at postnatal week 1, maintained at some physiological levels in the adult. Immunofluorescence staining showed that PSD-95 mainly distributed in the spinal gray matter during the early postnatal period, where it co-localized with the marker of neuron （NeuN） and synapse （synapsin）. In the adult rat, PSD-95 extensively distributed in the ventral horn, dorsal horn and white matter, where it respectively co-localized with NeuN, synapsin and the marker ofmicroglia （OX-42）. Conclusions： The protein and mRNA expression of PSD-95 appear a changeable character during spinal cord development. At the critical postnatal period, PSD-95 mainly distributes in the motor neurons of ventral horn and sensory neurons of dorsal horn. These results indicate that PSD-95 participates in the development and maturation of neuron.