饮食核酸对不同龄小鼠免疫功能的影响

THE EFFECT OF DIETARY NUCLEIC ACID ON IMMUNE FUNCTION IN MICE AT DIFFERENT AGES

目的 探讨饮食核酸对小鼠增龄性免疫功能变化的影响。方法 选取青龄 ( 1 2周龄 C57BL/6)、老龄 ( 1 5月龄 BALB/c)小鼠各随机分为 3组 ,在普通饮食饲喂的基础上 ,各组分别每日灌胃 2 0 mg/kg bw的低剂量、1 0 0 mg/kg bw的高剂量饮食核酸提取物 (低、高剂量实验组 )和0 .1 mol/L的柠檬酸钠缓冲液 (对照组 ) ,另选 6周龄 BALB/c小鼠作为幼龄对照组 ,每日灌胃柠檬酸钠缓冲液。观察中枢免疫器官胸腺与外周免疫器官脾脏的脏器指数、脾淋巴细胞 DNA合成能力、细胞因子白介素 - 2 ( IL- 2 )及肿瘤坏死因子 ( TNF)活性的变化。结果 青龄鼠高、低剂量饮食核酸补充组与其对照组比 ,胸腺指数、脾脏指数、脾淋巴细胞增殖能力、IL- 2及 TNF活性均显著增加( P<0 .0 5) ,但不同剂量核酸补充组间无显著差异。老龄鼠高剂量核酸补充组的胸腺指数、脾淋巴细胞增殖能力、IL- 2及 TNF活性均显著高于低剂量核酸补充组和其对照组 ( P<0 .0 5) ;但胸腺指数高剂量核酸补充组仍低于幼龄对照组 ,低剂量核酸补充组脾淋巴细胞增殖能力和 IL- 2活性也明显高于其对照组 (差异均为 P<0 .0 5) ;低剂量核酸补充组 IL - 2和 TNF活性与幼龄组间无差异。结论 饮食核酸既是生命早期和维持正常免疫的必需营养物质 ,还可显著改善小鼠增龄性?

Objective: To study the effects of dietary nucleic acid on age related changes of immune functions in natural aging mice. Methods: The young C57BL/6 mice aged 12 weeks and the old BALB/c mice aged 15 months were divided into three groups respectively, i.e., control group, low and high dosage (20mg·kg bw -1 ·d -1 and 100mg·kg bw -1 ·d -1 respectively) nucleic acid supplemented groups, and fed for 5 weeks. We also set up an infant control group by using 6 weeks old BALB/c mice. Results: In young mice groups, the splenic and thymic indices, splenic stimulation index and production of IL 2 and TNF of spleen cells were increased significantly in dietary nucleic acid supplemented groups (P<0.05), but there was no difference between nucleic acid supplemented groups; in old mice groups, the thymic index, splenic stimulation index and production of IL 2 and TNF of spleen cells were increased significantly in the high dosage nucleic acid supplemented group compared with old control group and low dosage nucleic acid supplemented group (P<0.05). Conclusion: Dietary nucleic acid can improve not only the development of immune system but also the age related changes of immune functions in mice. The old mice need higher supplemented dosage of dietary nucleic acid than young mice. [WT5”FZ]