Mocchegiani E, Santarelli L, Muzzioli M, Fabris N
Gerontology Research Department, Italian National Research Centres on Ageing (INRCA), Ancona, Italy.
Int J Immunopharmacol. 1995 Sep;17(9):703-18. doi: 10.1016/0192-0561(95)00059-b.
With advanced ageing the zinc pool undergoes progressive reduction as shown by the low zinc plasma levels and the negative crude zinc balance, both in humans and in rodents. It has been suggested that such zinc deficiency might be involved in many age-related immunological dysfunctions, including thymic failure. The relevance of zinc for good functioning of the entire immune system is, at present, well documented. In particular, zinc is required to confer biological activity to one of the best-known thymic peptides, thymulin, which is responsible for cell-mediated immunity. In deep zinc deficiencies, in humans and other animals, the low thymulin levels are due not to a primary failure of the thymus, but to a reduced peripheral saturation of thymic hormones by zinc ions. In aged mice both a reduced peripheral saturation of the hormone and a decreased production by the thymus were present. Oral zinc supplementation in old mice (22 months old) for 1 month induced a complete recovery of crude zinc balance from negative (-1.82) to positive values (+1.47), similar to those of young animals (+1.67). A full recovery of thymic functions with a regrowth of the organ and a partial restoration of the peripheral immune efficiency, as measured by mitogen responsiveness (PHA and ConA) and natural killer cell (NK) activity, were observed after zinc supplementation. These findings clearly pin-point for relevance of zinc for immune efficiency and suggest that the age-related thymic involution and peripheral immunological dysfunctions are not intrinsic and irreversible events but are largely dependent on the altered zinc pool.
随着年龄的增长，锌池会逐渐减少，这在人类和啮齿动物中都表现为血浆锌水平降低和锌的粗平衡为负。有人认为，这种锌缺乏可能与许多与年龄相关的免疫功能障碍有关，包括胸腺功能衰竭。目前，锌对整个免疫系统正常运作的相关性已有充分记录。特别是，锌是赋予最著名的胸腺肽之一胸腺素生物活性所必需的，胸腺素负责细胞介导的免疫。在人类和其他动物严重缺锌的情况下，胸腺素水平低并非由于胸腺的原发性衰竭，而是由于锌离子对胸腺激素的外周饱和度降低。在老年小鼠中，既存在激素外周饱和度降低，也存在胸腺分泌减少。给老年小鼠（22个月大）口服锌补充剂1个月，可使锌的粗平衡从负值（-1.82）完全恢复到正值（+1.47），与年轻动物（+1.67）相似。补充锌后，观察到胸腺功能完全恢复，器官再生，外周免疫效率部分恢复，这通过丝裂原反应性（PHA和ConA）和自然杀伤细胞（NK）活性来衡量。这些发现清楚地表明了锌对免疫效率的相关性，并表明与年龄相关的胸腺退化和外周免疫功能障碍不是内在的和不可逆转的事件，而是在很大程度上取决于锌池的改变。
