大鼠生后早期脑内小胶质细胞形态学研究

目的:观察大鼠生后早期脑内小胶质细胞的形态特点、进入中枢神经系统的途径、迁移的方式以及与时间的关联性。方法:选用生后1(postnatalday1,P1)、3、10、14、21d的SD大鼠各3只,雌雄不限。常规灌流固定,完整取出脑组织,使用恒冷冰冻切片机切脑片,片厚10μm。脑组织切片行免疫组织化学染色检测OX-42阳性小胶质细胞。结果:(1)SD大鼠生后1～2周,白质区可见圆形、阿米巴样、初级分支状小胶质细胞,数量由少到多,至P10达高峰;灰质区细胞呈多形性改变,以初级分支状细胞为主,数量逐渐增多;(2)小胶质细胞迁移入脑的路径主要有脑室、脑膜和血管路径。迁移方式为"切线式"迁移和"放射状"迁移。结论:(1)SD大鼠生后早期小胶质细胞一直处于连续的、动态的发育过程,至P21接近成熟;(2)在此阶段,阿米巴样小胶质细胞或初级分支小胶质细胞沿白质通路迁移,P10达迁移和增殖的高峰。

Microglia morphological development at early stage of life in rat brain

Objective:To observe the microglia morphological development,the approach into the central nervous system and the migrating way and the relevance with time at the early stage of life in rat brain.Methods:Three SD rats in every time,either male or female,of postnatal day 1(P1),3,10,14,and 21 were used.The rats brain tissues were fixed with conventional perfusion and taken out completely.Then rats were cut into sections(10 μm for each) with freezing microtome.The immunohistochemical method was used to detect OX-42 immunoreactivity in microglia.Results:(1) For the SD rats of postnatal week 1-2,the round,ameboid and primary branched microglia could be seen in the white matter.The number of OX-42-immunoreactive cells increased gradually,and reached peak at P10.In the gray matter,the cells had pleomorphic changes,and they were mainly primary branched.The number of cells increased gradually;(2) The approaches through which microglia migrated into the brain included ventricle,meninges and vessels.The migrational modes was "tangential" and "radial".Conclusion:(1) At the early stage of life of SD rats,microglia develops in the continuous and dynamic mode,and matured at P21;(2) At the same time,ameboid or primary branched microglia migrates through the white matter,and the number of them reach peak at P10.