C57／BL6小鼠小脑发生发育及衰老的形态学变化

Morphological changes in the development and aging of cerebellum in C57/BL6 mice

目的：观察C57／BL6小鼠小脑发生发育及衰老的形态学变化规律。方法：应用石蜡连续切片、H-E染色结合体视学方法对胚龄（E）10、12、14、16、18、20d和生后（P）1、3、7、14、21、28d的仔鼠及生后2、3、6、15个月（M）的C57／BL6小鼠小脑的形态学变化进行系统观察和定量分析。结果：E12d小脑原基出现。E16d小脑半球、蚓部及皮质的外颗粒层出现。E18d分子层的原基出现，小脑表面出现沟回结构。P1d皮质分为外颗粒层、分子层、浦肯野细胞层和内颗粒层4层。P7d皮、髓质分界清楚。P21d外颗粒层消失，皮质分为分子层、浦肯野细胞层和颗粒层3层。体视学分析显示，3个月之前，小脑总体积、皮质和髓质的体积、皮质各层（分子层、浦肯野细胞层和内颗粒细胞层／颗粒细胞层）的体积均逐渐增加，以P3－14d增长最快；3个月之后趋稳定。E18d－P14d，外颗粒层体积先增大后减小，P21d完全消失。结论：E12d－P21d是小鼠小脑发生发育的关键时期，细胞经历了增殖、分化和迁移，外颗粒层可能参与分子层和内颗粒层的形成。

Objective： To investigate the morphological changes in the development and aging of cerebellum in C57/BL6 mice. Methods： Serial sections, H-E stainning and stereological methods were used to analyze the morphological changes of C57/ BL6 mice cerebellum on embryonic （E） 10, 12, 14, 16, 18, 20 d （day） and postnatal （P） 1, 3, 7, 14, 21, 28 d and 2 M （month）, 3 M, 6 M, 15 M. Results： Cerebellum primordium appeared on E12 d. Cerebellar hemisphere, cerebellar worm and external granular layer appeared on E16 d. On E18 d, molecular layer primordium appeared and some gyule appeared on the surface of cerebellum. Then, on P1 d, the cortex was divided into 4 layers： external granular layer, molecular layer, Purkinie layer and internal granular layer. The demarcation was distinct between the cortex and medulla on P7 d and the external granular layer disappeared on P21 d. The volume of the cerebellum, cortex and medulla, every layer of cortex, excepting the external granular layer which increased firstly and then decreased and disappeared on P21 d, increased gradually before 3 M, and unchanged after then. Conclusion： The important stages in the development of mice cerebellum were on E12 d-P21 d, when the cells generated, differentiated and migrated. The external granular layer may take part in the formation of molecular layer and internal granular layer.