不同Reelin基因型小鼠海马结构组织学差异

Histological differences of hippocampal formation in different Reelin genotype mice

目的通过对不同Reelin基因型小鼠海马区组织学结构的比较分析,为Reelin在海马结构形成中的作用提供依据。方法选择杂合子Reelin小鼠繁殖后代,在出生后10d进行基因型鉴定,设Reelin+/+、Reelin+/-和Reelin^-/-3组,每组3只小鼠。鉴定后的小鼠通过4%多聚甲醛心脏灌注后剥离全脑,通过多聚甲醛固定、蔗糖脱水后冷冻切片,采用4’6-二脒基-2-苯基吲哚(DAPI)为细胞核染色,用免疫荧光标记T-box brain gene 1(Tbr-1)、神经元核抗原(Neu N)和GFAP特异性表达的细胞,光学显微镜下观察、摄片后对结果进行分析。结果从DAPI染色的细胞核及Tbr-1、Neu N和GFAP标记的细胞结构可以看出,Reelin+/+型小鼠和Reelin+/-型小鼠海马区都具有相似的结构,但将Reelin+/+和Reelin^-/-型小鼠相比较,Reelin^-/-型小鼠海马结构模糊,齿状回细胞向门区扩散,海马本部的细胞层结构紊乱,出现密集双细胞带,GFAP标记细胞减少。结论 Reelin缺失表达对小鼠大脑正常结构的形成具有明显的影响。在Reelin表达缺失后海马区齿状回细胞分布弥散,海马本部细胞层的分布紊乱,胶质细胞及纤维分布减少。

Objective To reveal scientific basis for the function of Reelin in the hippocampal formation by comparing the histological structures of the hippocampus in different Reelin genotype mice. Methods Heterozygous Reelin mice offspring were used, and genotype identification was performed 10 days after birth. The mice were divided into three groups： Reelin^＋/＋ , Reelin ^＋/- and Reelin^-/- , 3 mice per group. After identification, the mice were perfused through the heart by 4% paraformaldehyde and the whole brain was collected. All samples were post-fixed by paraformaldehyde, sucrose dehydration and finally cut into frozen coronal slices. 4 ＇ 6-diamidino-2-phenylindole （DAPI） was used to stain nuclei, and immunofluorescence was performed to label T-box brain gene 1 （Tbr-1） , neuronal nuclei （NeuN） and GFAP specific expression cells. Fluorescence microscope was used for observation and analysis. Results According to the DAPI stained nuclei and Tbr-1, NeuN and GFAP labeled cell structures, Reelin ^＋/＋ and Reelin ^＋/- mice in hippocampal area had similar structures, but in comparison with the Reelin ^＋/＋and Reelin ^-/- mice, dentate gyrus cells of the Reelin^ -/- type mice spread to the gate area, the cell layer of hippocampal structure disordered, and GFAP labeled cells reduced. Conclusion Reelin has obvious effect on normal formation of mouse brain structure. Under the condition of Reelin knock out mouse, the dentate gyrus area cells are dispersed, the cell layer of the hippocampus is disordered, and glial cells and fiber distribution both are reduced.