Effects of chronic stress of early tooth extraction on hippocampus in senescence-accelerated mice

该评价是长期牙齿缺失是否诱导衰老加速小鼠（SAMP 8）海马体的功能和形态变化。结果表明：1、老年或成年长期缺牙组小鼠血浆皮质酮浓度作为应激源显著高于同龄对照组; 2、成年或老年长期缺牙组小鼠在Morris水迷宫中的学习和空间记忆能力显著低于同龄对照组; 3、成年或老年长期缺牙组小鼠在Morris水迷宫中的学习和空间记忆能力显著低于同龄对照组。与年龄匹配的对照组相比，成年和老年长期失牙组海马CA 3区神经元数量显著减少，而成年和老年长期失牙组与年龄匹配的对照组相比，海马CA 1区和齿状回（DG）区神经元数量无显著差异。与年龄匹配的对照组相比，在成熟或老年长期牙齿缺失组的海马CA 3区GFAP阳性细胞的数量显着增加。而成年和老年小鼠海马CA 1区和DG区BrdU阳性细胞数无显著性差异。5、成年和老年长期缺牙组海马DG区BrdU阳性细胞数较同龄对照组明显增多。注意到，与年龄匹配的对照组相比，成熟或老年长期牙齿缺失组的突触溶素表达显著降低。长期牙齿缺失增强了衰老对小鼠海马体的影响。

This evaluations were whether long-term tooth loss induces functional and morphologic changes in the hippocampus in senescence-accelerated mice(SAMP8). The teeth were extracted at an early age.The results were as follow.1, Plasma corticosterone concentration as a stressor was significantly higher in old or mature mice with long-term tooth loss groups than in the age-matched controls.2, In the Morris water maze learning and spatial memory trials was significantly slower in the mature or old long-term tooth loss groups compared with the age-matched controls.3, The number of hippocampal neurons was significantly reduced in the CA3 region of the hippocampus in the mature and old long-term tooth loss groups compared with their age-matched controls, but there was no significant difference in the CA1 or dentate gyrus(DG) region between the mature or old long-term tooth loss groups and their age-matched controls.4, The number of GFAP-positive cells was significantly higher in the CA3 region of the hippocampus in the mature or old long-term tooth loss groups compared with age-matched controls. However, no significant difference was observed in the CA1 or DG of the hippocampus in the mature or old mice.5, The number of BrdU-positive cells was significantly increased in the DG of the hippocampus in the mature or old long-term tooth loss groups compared with age-matched controls.6, In the hippocampus, note the significant decrease in synaptopysin expression in the mature or old long-term tooth loss groups compared with age-matched controls.The findings indicated that long-term tooth loss enhances the effects of aging on the hippocampus in mice.