血清甲状腺素水平及细胞免疫功能的增龄性变化

Aging-associated changes in serum thyroid hormone levels and cellular immune function

摘要:

目的 探讨血清甲状腺素水平与细胞免疫功能的增龄性变化。方法 在完善SENIEUR协议的基础上筛选出78例高龄健康老年组（≥80岁）、128例非高龄健康老年组（60～79岁）、60例非老年健康体检组（20～59岁）。采用化学发光法检测血清甲状腺素水平; 流式细胞仪检测外周血单个核细胞（PBMC）表面人白细胞抗原DR位点（HLA-DR）的表达, T淋巴细胞、B淋巴细胞、自然杀伤细胞（NK细胞）的绝对值以及T细胞亚群CD4＋/CD8＋的比值; 各组随机选择10例体检者, 分离PBMC获得T细胞, 用四甲基偶氮唑蓝（MTT）法检测T细胞经体外植物血凝素（PHA）刺激后的增殖能力。结果 3组健康体检者的血清三碘甲状腺原氨酸（T3）、四碘甲状腺原氨酸（T4）、游离三碘甲状腺原氨酸（FT3）、游离四碘甲状腺原氨酸（FT4）以及血清促甲状腺素（TSH）水平均无显著性差异（P＞0.05）; 3组健康体检者的PBMC表面HLA-DR的表达以及外周血T细胞、NK细胞、B细胞数目的绝对值均无显著性差异（P＞0.05）, CD4＋, CD8＋的T细胞亚群绝对值以及CD4＋/CD8＋比值无显著性差异（P＞0.05）; 3组T细胞在体外经PHA刺激后其增殖能力有显著性差异, 非老年健康体检组最强、高龄健康老年组最弱（P＜0.05）。结论 在完善SENIEUR协议基础上选择研究对象, 结果发现, 健康体检者的血清甲状腺素水平随增龄无明显变化, 外周血免疫细胞数量随增龄也无明显改变, 但免疫细胞的功能随增龄明显减低。

Abstract:

Objective To investigate aging-associated changes in serum thyroid hormone levels and cellular immune function. Methods Three groups of healthy subjects were recruited based on SENIEUR protocol criteria: group A, aged over 80 years (n = 78); group B, aged 60-79 years (n = 128); and group C, aged 20-59 years (n = 60). Serum thyroid hormone level was determined by chemiluminescence method. Peripheral blood T cells, B cells, and NK cells numbers were evaluated by flow cytometry and T cell subsets CD4＋/CD8＋ ratios were also calculated. In addition, 10 subjects were randomly selected from each group and their T cells were isolated from peripheral blood mononuclear cells (PBMC); T cell proliferation after phytohemagglutinin (PHA) stimulation was determined by MTT assays. Results There was no significant difference in T3 thyroid hormone (T3), T4 thyroid hormone (T4), free T3 (FT3), free T4 (FT4) and thyroid stimulating hormone (TSH) among the three groups (P＞0.05). There was no marked difference in PBMC surface HLA-DR expression, as well as the absolute numbers of peripheral blood T cells, NK cells, or B cells among the three groups (P＞0.05). Moreover, no significant difference was observed in the numbers of CD4＋ cells, CD8＋ cells, or the CD4＋/CD8＋ ratios (P＞0.05). However, T cell proliferation was markedly increased after PHA stimulation, with the highest level in group C and the lowest level in group A (P＜0.05). Conclusion The study recruits subjects based on the SENIEUR protocol criteria, and our findings suggest that the levels of serum thyroid hormone and the numbers of immune cells remain unchanged with increasing age. However, there is a trend for decreased cellular immune function with increasing age.