中脑红核突触素的表达与突触发育的关系

摘要

Objective: To investigate the relationship between the expression of synaptophysin (SYN) and the development of synapse in the red nucleus of different periods of human fetus. Methods:Thirty-two fetuses were divided into 5 groups by different age. Immunohistochemical technique was used to observe the expression of SYN in the red nucleus of different periods of human fetus. Computer image analysis system was used to measure the average optical density of SYN in the red nucleus of different stages of human fetus, meanwhile, the ultrastructural change of synaptic development in the red nucleus was observed under an electron microscope. Results: (1) Under the light microscope, the SYN immunoreactive (SYN-IR) products were observed in the red nucleus of human fetus among 16-39 weeks group. With the age increasing, the SYN-IR products were increased significantly (P<0. 05). In 16-20 weeks group, the SYN-IR products increased rapidly; in 21-29 weeks group the SYN-IR products increased slowly; in 30-39 weeks group, the SYN-IR products increased quickly. In 16-24 weeks group, the SYN-IR products were found in both the cytoplasm and neurite. In 25-39 weeks group, the SYN-IR products were mainly located around the neurite of neurons in the red nucleus, and no SYN-IR products were found within the cytoplasm. The SYN-IR products appeared in the form of fine brown granules, the granules color and quantity increased significantly with the age increasing. (2) Under the transmission electro-microscope, the synaptic structure could be seen in the red nucleus of human fetus in 17-36 weeks. With the age increasing, the amount increased and the structure completed gradually for the synapse. Conclusion: The above results suggest that the expression of SYN can reflect the developing degree of the neurons in the midbrain, and the change of SYN expression in the red nucleus might be related to the developmental regulation of the synapse in the midbrain. The expression of SYN is synchronous with the development of synapse.%目的:为探讨突触素在不同周龄阶段胎儿中脑红核的表达及其与红核突触发育的关系.方法:收集因故终止妊娠的胎儿32例,胎龄为16～39周,按周龄大小分为5组.利用免疫组织化学方法观察突触素在不同周龄阶段胎儿红核的表达情况,应用计算机图像分析技术测量突触素在不同周龄阶段胎儿红核表达的平均光密度.同时中脑取材,常规透射电镜技术处理,电镜下观察红核突触发育的超微结构改变.结果:(1)光镜下16～39周,各组红核神经元均可见突触素免疫反应产物表达,其表达量随周龄的增加而增多,各组间差异性明显.突触素表达量16～20周增加迅速,21～29周增加较慢,30～39周快速增加.突触素免疫反应产物在16～24周的神经元胞质和突起均有表达,25～39周主要在红核神经元突起部表达,神经元胞体内免疫产物表达不明显.免疫反应产物呈棕黄色点状或颗粒状,随着周龄的增加阳性颗粒的量和颜色增加显著.(2)透射电镜下17～36周胎儿红核部可见不同发育程度的突触结构,随着周龄的增加突触数量增多,其结构逐渐清晰和完整.结论:突触素在红核表达的情况可以反映胎儿中脑神经元的发育程度,其表达的变化可能与中脑神经元突触发育的规律有关,突触素的表达变化与突触结构的发育程度是一致的.