Up-regulation of human immune system function by Donkey’s Milk

Donkey’s milk represents a good alternative to human milk because of its chemical characteristics similar to those of human’s. In present study, the pro- and anti-inflammatory effects of donkey’s milk were evaluated on peripheral blood mononuclear cells (PBMCs). PBMCs were isolated from 12 young and 12 aged normal subjects. PBMCs were cultured with or without the optimal and non-cytotoxic dose of pasteurized donkey’s milk, and polymyxin B was used to inhibit the possible endotoxin contamination. Following 18 hours incubation, culture supernatants were harvested to measure the secreted Tumor necrosis factor-α (TNF-α), Interleukin-6 (IL-6), Interleukin-8 (IL-8) and Interleukin-10 (IL-10) by ELISA. Donkey’s milk significantly increased TNF-α (p= 0.01), IL-8 (p< 0.0001), IL-6 (p< 0.0001) and IL-10 (p= 0.01) levels in PBMCs. In addition, the levels of IL-6 (p= 0.002), IL-8 (p= 0.002) and TNF-α (p= 0.002) from aged subjects were significantly higher compared with young subjects. In contrast with these data, the level of IL-10 was markedly reduced from aged subjects (p= 0.02). Considering the immune-potentiation effects of donkey’s milk, it is suggested investigating milk as a beneficial dietary component for up-regulating the immune response in aged people.

驴乳因化学组成与母乳高度相似，是母乳的优质替代选择。本研究针对驴乳对外周血单个核细胞（peripheral blood mononuclear cells, PBMCs）的促炎及抗炎效应展开评估。实验所用PBMCs分离自12名青年健康受试者与12名老年健康受试者。将PBMCs分别在添加/不添加经巴氏灭菌的驴乳最优无细胞毒性剂量的培养基中培养，同时加入多粘菌素B以抑制可能存在的内毒素污染。经18小时孵育后收集培养上清液，采用酶联免疫吸附测定（enzyme-linked immunosorbent assay, ELISA）检测上清中分泌的肿瘤坏死因子-α（Tumor necrosis factor-α, TNF-α）、白细胞介素-6（Interleukin-6, IL-6）、白细胞介素-8（Interleukin-8, IL-8）及白细胞介素-10（Interleukin-10, IL-10）的含量。实验结果显示，驴乳可显著上调PBMCs中TNF-α（p=0.01）、IL-8（p<0.0001）、IL-6（p<0.0001）及IL-10（p=0.01）的水平。此外，老年受试者PBMCs分泌的IL-6（p=0.002）、IL-8（p=0.002）及TNF-α（p=0.002）水平显著高于青年受试者。与之相反，老年受试者的IL-10水平显著降低（p=0.02）。鉴于驴乳具有免疫增强效应，本研究提示可进一步探究驴乳作为有益膳食成分，用于上调老年人群的免疫应答水平。