大鼠胸腺增龄变化的形态学研究

目的:探讨胸腺组织结构的增龄性形态学改变,了解引起胸腺萎缩的可能机制。方法:大鼠胸腺切片制作、染色,在光镜、电镜下观察胸腺主要结构的增龄性变化,对胸腺皮、髓质的细胞密度之比的变化进行测试。结果:光镜观察显示,随着年龄增长,胸腺皮质变薄,胸腺细胞稀疏,皮、髓质分界不清;胸腺皮、髓质的细胞密度比例随增龄降低。而电镜下观察到胸腺细胞退化萎缩,出现了大量的脂肪、纤维、凋亡的胸腺细胞,线粒体肿胀,嵴减少,出现大小不等的空泡,核固缩。结论:随着鼠龄增大,胸腺细胞及上皮性网状细胞等线粒体结构的退化数目减少,胸腺萎缩退化。

A Study on the Morphologic Changes of Rat Thymus with Increasing Age

Objective: To explore the morphologic changes of the structurally atrophied thymus in rat with age change and its possible mechanism of thymus involution.Methods: The thymus was embedded with paraffin and stained with hematoxylin and eosin.The ultrastructure changes of the thymus were observed under high power microscope and electron microscope.The thymocytes density ratio of cortex to medulla was studied quantitatively with analyzed statistics.Results:It was shown under the microscope,that in aged rat the thymic cortex became thiner and thymocytes was fewer and there was no distinguished line between cortex and medulla,the thymocytes density ratio of cortex to medulla got lower,and the thymocyte degeneratied and involuted,a great numer of fat,fibrils and apoptotic thymocytes were found,its mitochondria became swollen and vacuolized,with the crista reduced and a large number of vacuoles seemed to take place.The nuclear became condensed and marginated.Conclusion: With increasing age,cells in the thymic cortex progressively reduce and thymus involutes.The structual mitochondria in thymocytes and reticular-epithelial cells degenerate.