不同年龄双峰驼海马的形态学变化及其神经生长因子的表达

目的 探讨胎驼、青年双峰驼及成年双峰驼海马不同区域内主要神经元形态特征变化及神经生长因子（NGF）的表达情况。 方法 应用常规石蜡切片Nissl染色及免疫组织化学方法，对胎驼、青年双峰驼和成年双峰驼海马CA1～CA3区锥体细胞、齿状回（DG)颗粒细胞的形态学变化进行研究，并观察了NGF的表达变化情况。 结果 Nissl染色结果显示，从胎驼到青年双峰驼再到成年双峰驼，海马各区锥体细胞和颗粒细胞的体积增大、密度降低、细胞的核体比减小。NGF免疫组织化学结果表明，成年双峰驼海马锥体细胞中NGF的表达量显著高于胎驼和青年双峰驼（P<0.01），颗粒细胞中NGF的表达量逐渐增加。 结论 从胎驼到成年双峰驼，海马中的主要神经元不断成熟，从体积小且少有突起和分支的神经元发育成为体积较大、具有明显形态和功能的神经元。NGF在成年双峰驼海马神经元中表达量最高，表明NGF可调节已分化的神经元，使其形态和功能发生改变以促进成年双峰驼与海马相关的学习记忆功能的逐步完善。

Morphological changes and expression of nerve growth factor of hippocampus in different ages of Bactrian camels

Objective To investigate morphological changes of neurons and the expression of nerve growth factor (NGF) in different areas of hippocampus in fetal, young and adult Bactrian camels. Methods Nissl staining was used to observe morphological changes of pyramidal cells in CA1-CA3 areas and granule cells of dentate gyrus. Immunohistochemical method was used to detect the expression of NGF of hippocampus in fetal, young and adult Bactrian camels. Results The results of Nissl staining showed that from fetal Bactrian camel to young Bactrian camel and to adult Bactrian camel, pyramidal cells in CA1-CA3 areas and granular cells in teh dentate gyrus enlarged in volume but decreased gradually in density with the growth of Bactrian camel. The proportion of nuclei in neurons also decreased. Immunohistochemical analysis revealed that the expression level of NGF in pyramidal cells of adult camel was significantly higher than the other two periods of Bactrian camel (P<0.01). Conversely, the expression level of NGF in granule cells increased consistently from fetal camel to adult camel. Conclusion From fetal Bactrian camel to adult Bactrian camel, the main neurons of hippocampus continuously become mature: neurons change from small and global cells which have little cytoplasm, to neurons which are large and have specific morphology and function. The high expression level of NGF in hippocampus of adult camel indicates that NGF could regulate differentiated neurons, propel morphological and functional changes in neurons, which will consequently contribute to the improvement of learning and memory functions of hippocampus in Bactrian camel.