大鼠生后早期脑内小胶质细胞形态学研究

The Research of Microglia Cytomorphology at Early Postnatal Period in Rat Brain

目的观察大鼠生后早期脑内小胶质细胞形态特点、进入CNS的途径、迁移的方式以及与时间的关联性。方法选用Sprague—Dawley（SD）大鼠生后1d（postnatalday 1，P1），3d、10d、14d，21d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方法检测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。

Objective To observe the characteristic changes, the approaches to CNS, the migratory ways and the relevance with time of microglia morphology at early postnatal period of the rat brain. Methods 15 Sprague - Dawley rats of postnatal lday, 3days, 10days, 14days and 21days were used in the experiment. Constant frozen slices with 10μm thick were tested with immunohistochemical staining for OX- 42 microglia. Results （1） Brain microglia of Sprague - Dawley rats underwent dynamic changes in morphology at early stage of life from postnatal day 1 to 21. They were round, amoeba - like and primitively ramified at white matter with the numbers increased and reached the peak at postnatal 10 days while pleomorphic cells were seen at gray matter, mainly the primitively ramified cells. The number was increased gradually. （2） Microglia migration into the brain from ventricle, meninges and blood vessels were all seen in present study and the migration style showed was the ＂tangent - type＂ and ＂radial like＂ . Conclusions （ 1 ） Cerebrum microglia of Sprague - Dawley rats have undergone continuous and dynamic changes in morphology at early stage of life. The mieroglia are almost mature at postnatal 21 days. （2 ） In this developing stage, the amoeboid or primitively ramified microglia migrate along the white matter and reach the peak of migration and proliferation at postnatal 10 days.