摘要
目的探讨大鼠胼胝体额区有髓神经纤维髓鞘超微结构的老年性改变。方法运用电子显微镜和三维体视学方法分别对年轻组(6月龄)、中老年组(18月龄)和老年组(27月龄)雌性Long-Evans大鼠大脑胼胝体额区有髓神经纤维超微结构进行定量研究。结果年轻组、中老年组和老年组的有髓神经纤维轴突平均直径(内径)、有髓神经纤维平均直径(外径)、平均内周长、平均外周长、髓鞘平均厚度均未见显著性改变。将有髓神经纤维髓鞘厚度按<0.2μm、0.2～0.4μm(不含0.4,以下类推)、0.4～0.6μm、0.6～0.8μm、0.8～1.0μm、≥1.0μm 6个段分别进行统计分析,结果显示,在0.2～0.4μm直径段内,中老年组和老年组髓鞘厚度较年轻组均存在显著降低(P<0.05);在0.4～0.6μm直径段内,老年组髓鞘厚度较年轻组存在显著性降低(P<0.05);在0.6～0.8μm直径段内,老年组髓鞘厚度较中老年组显著性降低(P<0.05)。结论胼胝体额区有髓神经纤维尤其是小直径的有髓神经纤维髓鞘厚度存在显著老年性降低。
Objective To explore the age-related changes of myelin sheath microstructure in the frontal region of corpus callosum.Methods Myelin sheath microstructure in the frontal region of corpus callosum of young（6 months old）,middle-aged（18 months old） and old-aged female（27 months old） Long-Evans rats were studied by electron microscope and unbiased stereological techniques.Results There was no significant change in mean diameter of axons（inner diameter）,mean diameter of myelinated fibers（external diameter）,mean inner perimeter,mean outer perimeter and mean thickness of myelin sheathes of myelinated nerve fibers in the frontal region of corpus callosum among the young,middle-aged and old-aged rats.The thicknesses of myelin sheaths of myelinated nerve fibers were divided into six intervals according to diameter of myelinated fibers（0.2 μm,0.2-0.4 μm,0.4-0.6 μm,0.6-0.8 μm,0.8-1.0 μm and ≥1.0 μm）,and the mean thickness of myelinated fibers in each interval was calculated.Within diameter from 0.2 μm to 0.4 μm,the mean thickness of myelin sheaths of the middle-aged and old-aged rats significantly decreased compared with that of the young rats.Within the diameter from 0.4 μm to 0.6 μm,the mean thickness of myelin sheaths of the old-aged rats significantly decreased compared with that of the young rats.Within the diameter from 0.6 μm to 0.8 μm,the mean thickness of myelin sheaths of the old-aged rats significantly decreased compared with that of the middle-aged rats.Conclusion There is a significant age-related decrease in myelin sheath thickness of myelinated fibers in the frontal region of corpus callosum,especially myelinated fibers with small diameters.
出处
《第三军医大学学报》
CAS
CSCD
北大核心
2011年第23期2476-2479,共4页
Journal of Third Military Medical University
基金
国家自然科学基金(30973155)
教育部博士点基金(200806310007)
重庆医科大学重点项目(XB2D200801)
重庆市自然科学基金重点项目(CSTC2009BA5035)~~
关键词
有髓神经纤维
髓鞘
胼胝体额区
体视学
myelinated nerve fibers
myelin sheaths
frontal region of corpus callosum
stereology
