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目的探讨雌性Long-Evans大鼠海马结构及其内有髓神经纤维的老年性改变。方法运用透射电子显微镜和体视学方法分别对5只青年(6月龄)、5只中老年(18月龄)和6只老年(28月龄)雌性Long-Evans大鼠海马结构及其内有髓神经纤维进行定量研究。结果青年组、中老年组和老年组大鼠的海马结构总体积,海马结构内有髓神经纤维的体积分数和总体积,有髓神经纤维的长度密度和有髓神经纤维平均直径均未见显著性改变。中老年组大鼠海马结构内有髓神经纤维总长度与青年组相比增加了63.6%,老年组有髓神经纤维总长度与中老年组相比下降了47.5%,老年组有髓神经纤维总长度与青年组比较下降了13.8%。结论本研究结果进一步支持正常老年大脑的有髓神经纤维存在广泛性老年改变。
Objective To investigate the changes of hippocampal structure and the changes of the myelinated nerve fibers in female Long-Evans rats. Methods The structures of hippocampus of 5 young (6 months old), 5 middle aged (18 months old) and 6 old (28 months old) female Long-Evans rats were observed by transmission electron microscopy and stereological methods. Myelinated nerve fibers for quantitative research. Results The total volume of hippocampal formation, the volume fraction of myelinated nerve fibers in hippocampal formation and the total volume, the length density of myelinated nerve fibers and the average diameter of myelinated nerve fibers were not significantly different in young, middle-aged and aged rats Sexual change. The total length of myelinated nerve fibers in hippocampal formation in middle-aged and elderly rats increased by 63.6% compared with that in youth group. The total length of myelinated nerve fibers in elderly group decreased by 47.5% compared with that in middle-aged and elderly groups. The total length of myelinated nerve fibers Compared with the youth group, the length decreased by 13.8%. CONCLUSIONS Our findings further support the widespread geriatric changes in myelinated nerve fibers in normal elderly brains.