Chen J, Astle C M, Harrison D E
Jackson Laboratory, Bar Harbor, Maine, USA.
J Gerontol A Biol Sci Med Sci. 1998 Sep;53(5):B330-7; discussion B338-9. doi: 10.1093/gerona/53a.5.b330.
Age-related changes in peripheral blood, spleen, and thymus of ad libitum (AL)-fed and dietary restricted (DR) C57BL/6J x CBA/CaH-T6/J F1 (B6CBAT6 F1) mice at young (3 mo), middle (16 mo), and old (30 mo) ages were studied to define how dietary restriction retards immune aging. Dietary restriction at 25% AL intake level initiated at weaning significantly reduced the rates of age-related declines in peripheral blood T helper cells, naive T helper cells, and naive cytotoxic T lymphocytes (CTLs). As a result, concentrations of these cell types in old DR mice were equivalent to 161%, 176%, and 250% of those in old AL controls. Dietary restriction also abolished age-related splenomegaly and decreased total splenocyte numbers in old DR mice. Dietary restriction did not prevent age-related decline in thymus size, but preserved thymus cellularity in old mice. Old DR mice had twice as many total thymocytes and 2.6 times as many CD4+CD8+ immature thymocytes as old AL controls. The correlations between total immature thymocytes and concentrations of circulating naive T helper cells and naive CTLs increase with age and become significant in old mice. Thus, dietary restriction preserves immature T-cell precursors in the thymus during aging to maintain higher concentrations of circulating T helper and naive T cells in peripheral blood.
研究了自由采食（AL）和饮食限制（DR）的C57BL/6J×CBA/CaH-T6/J F1（B6CBAT6 F1）小鼠在年轻（3个月）、中年（16个月）和老年（30个月）时外周血、脾脏和胸腺的年龄相关变化，以确定饮食限制如何延缓免疫衰老。断奶时开始的25%AL摄入量水平的饮食限制显著降低了外周血T辅助细胞、初始T辅助细胞和初始细胞毒性T淋巴细胞（CTL）与年龄相关的下降速率。结果，老年DR小鼠中这些细胞类型的浓度分别相当于老年AL对照小鼠的161%、176%和250%。饮食限制还消除了老年DR小鼠与年龄相关的脾肿大，并减少了脾细胞总数。饮食限制并未阻止胸腺大小与年龄相关的下降，但保留了老年小鼠胸腺的细胞数量。老年DR小鼠的总胸腺细胞数量是老年AL对照小鼠的两倍，CD4+CD8+未成熟胸腺细胞数量是老年AL对照小鼠的2.6倍。总未成熟胸腺细胞与循环初始T辅助细胞和初始CTL浓度之间的相关性随年龄增加，在老年小鼠中变得显著。因此，饮食限制在衰老过程中保留了胸腺中的未成熟T细胞前体，以维持外周血中循环T辅助细胞和初始T细胞的较高浓度。
