C57/BL6小鼠海马结构发生、发育和衰老过程中的细胞凋亡

目的探讨C57/BL6小鼠海马结构发生发育及衰老过程中细胞凋亡的变化规律。方法采用Hoechst 33258染色检测不同阶段C57/BL6小鼠海马结构中的细胞凋亡;免疫荧光和Western blotting技术检测不同阶段C57/BL6小鼠海马结构中Caspase-3的表达。结果 Hoechst 33258染色结果显示:胚龄(embryonic day,E)12d～18d凋亡细胞渐增多;生后(postnatal day,P)1～7d渐减少;P14d～2月主要于齿状回、海马沟和海马槽的白质区可见少量凋亡细胞;3月～18月仅在齿状回亚颗粒细胞层见零星分布。阿蒙角(Ammons horn,CA)及齿状回(dentate gyrus,DG)多形层及分子层细胞凋亡率P1～P14d渐下降。CA及DG主细胞层细胞凋亡率P1d最高,以后逐渐降低。Caspase-3免疫荧光结果示:E12～E16d阳性表达细胞渐增多;E18～P3d继续增多,主要分布于CA锥体层及DG颗粒层;P5～P14d分布渐减少;P21d～18月各区仅见少量阳性细胞表达。Western Blotting结果示E18～P3dCaspase-3表达增加;P5～P21d表达降低;P21d后趋于稳定。结论生后1d为小鼠海马结构凋亡高峰;Caspase-3为重要凋亡因子。

Cell apoptosis during the development and aging of hippocampus in C57/BL6 mice

Objective To investigate cell apoptosis during the development and aging of C57/BL6 mouse hippocampal formation.Methods Hoechst33258 staining was used to detect cell apoptosis of C57/BL6 mouse hippocampal formation at different stages.Immunofluorescence technique and Western blotting were used to detect the expression of Caspase-3 of C57/BL6 mouse hippocampal formation at different stages.Results Hoechst33258 staining showed that apoptotic cells increased gradually from embryonic(E) 12 day(d) to E18d while postnatal(P) P1-P7 d apoptotic cells gradually decreased.At P14 d-2 month a few apoptotic cells were mainly distributed in dentate gyrus(DG)and hippocampal fissure and hippocampal alveus.At 3-18 month apoptotic cells were sparsely scattered only in sub-granule cell layers of DG.At P1-P14 d the apoptosis rate of polymorphic layer and molecular layer in Ammon’s horn(CA)and DG decreased.Principal cell layers of CA and DG had the highest apoptosis rate at P1d,and then gradually decreased.Caspase-3 immunofluorescence showed at E12-E16 d positive cells increased and at E18-P3 d there were more positive cells and they were distributed mainly in the CA pyramidal layer and DG granular layer.At P5-P14 d the number of positive cells gradually decreased.At P21 d-18 month only a few positive cells could be seen in various regions.The results of Western blotting showed that the expression of Caspase-3 increased at E18-P3 d,decreased at P5-P21 d and stabilized after P21 d.Conclusion Postnatal day one is the peak of cell apoptosis in mouse hippocampal formation and Caspase-3 is an important apoptosis factor.