增龄对大鼠胸腺形态结构及细胞免疫功能的影响

目的:系统地探讨不同年龄大鼠淋巴细胞转化规律与胸腺质量、胸腺指数增龄变化引起胸腺萎缩的机制。方法:大鼠按年龄分组,测定其胸腺质量及体质量大小,应用植物血凝素(PHA)丝裂原诱导的脾细胞增殖反应,利用噻唑蓝(MTT)颜色反应法观察淋巴细胞转化;在光镜、电镜下观察胸腺主要结构的年龄变化。结果:测定显示,随着年龄的增加,胸腺指数明显下降。脾脏淋巴细胞的增殖活性明显下降。同时胸腺组织的光、电镜观察胸腺皮质变薄,胸腺细胞稀疏,皮、髓质分界不清;大量的脂肪、纤维代替了部分胸腺细胞,线粒体肿胀,嵴减少,部分细胞凋亡。结论:增龄过程中,大鼠胸腺萎缩退化,胸腺指数下降;免疫结构退化与功能下降。

Effects of Ageing on Thymic Structure and the Immunologic Function in Rat

Objective:To investigate systemly the rule of lymphocyte transformation,and based on the changes of thymus weight and thymus index in rat with ageing change,its possible mechanism of thymus involution.Methods:Accordring to their ages,the rat were randomized into three groups respectively,to determin the thymus weight and thymus index.Lymphocyte cell proliferation was stimulated by PHA.MTT colorimitric method was used to determine lymphocyte transformation.The ultrastructure changes of the thymus in rats were observed under high power microscope and electron microscope.Results:It was showed that,the thymus index was decreasing with age increased.Lymphocyte cell proliferation activity markedly fell.The Thymic cortex became thin.The thymocytes density ratio of cortex to medulla decreased with aging,no distinguished line between cortex and medulla with age increased in the high power microscope.A great numer of fat and fiber were instead of thymocyte and other structure.In the apoptotic thymocytes,its mitochondria became swollen and vacuolized,with the crista reduced.Some thymocytes apoptosis.Conclusion:With aging thymus involution and thymus index decrease.Immunologic function decrease.