Division of Nutritional Sciences, University of Illinois, Urbana, IL 61801, USA.
Brain Behav Immun. 2010 May;24(4):631-40. doi: 10.1016/j.bbi.2010.01.015. Epub 2010 Feb 6.
Peripheral activation of the immune system by infectious agents triggers the brain-cytokine system causing sickness behaviors which profoundly impact well-being. Dietary fiber is a beneficial foodstuff that, from a gastrointestinal tract perspective, exists in both insoluble and soluble forms. We show that a diet rich in soluble fiber protects mice from endotoxin-induced sickness behavior by polarizing mice Th2 when compared to a diet containing only insoluble fiber. Mice fed soluble fiber became less sick and recovered faster from endotoxin-induced sickness behaviors than mice fed insoluble fiber. In response to intraperitoneal endotoxin, mice fed soluble fiber had up-regulated IL-1RA and reduced IL-1beta and TNF-alpha in the brain as compared to mice fed insoluble fiber. Importantly, mice fed soluble fiber had a basal increase in IL-4 in the ileum and spleen which was absent in MyD88 knockout mice. Con-A stimulated splenocytes from mice fed soluble fiber showed increased IL-4 and IL-5 and decreased IL-2, IL-12 and IFN-gamma when compared to mice fed insoluble fiber. Likewise, endotoxin-stimulated macrophages from mice fed soluble fiber demonstrated decreased IL-1beta, TNF-alpha, IFN-gamma, IL-12 and nitrate and increased IL-1RA, arginase 1 and Ym1 when compared to mice fed insoluble fiber. Finally, the behavioral protection afforded by feeding mice soluble fiber was reduced in IL-4 knockout mice, as was the impact of soluble fiber on Con-A stimulated splenocytes and endotoxin activated macrophages. These data show that a diet rich in soluble fiber protects against endotoxin-induced sickness behavior by polarizing mice Th2 and promoting alternative activation of macrophages.
病原体对外周免疫系统的激活会触发脑-细胞因子系统，导致疾病行为，从而深刻影响幸福感。膳食纤维是一种有益的食物，从胃肠道的角度来看，它存在于不溶性和可溶性两种形式。我们表明，富含可溶性纤维的饮食通过使 Th2 极化来保护小鼠免受内毒素引起的疾病行为，而与仅含有不溶性纤维的饮食相比。与喂食不溶性纤维的小鼠相比，喂食可溶性纤维的小鼠的疾病症状减轻，并且从内毒素引起的疾病行为中恢复得更快。与喂食不溶性纤维的小鼠相比，喂食可溶性纤维的小鼠在腹腔内注射内毒素后，脑中的 IL-1RA 上调，IL-1beta 和 TNF-alpha 减少。重要的是，与 MyD88 敲除小鼠相比，喂食可溶性纤维的小鼠在回肠和脾脏中存在基础增加的 IL-4。与喂食不溶性纤维的小鼠相比，Con-A 刺激的喂食可溶性纤维的小鼠的脾细胞显示出增加的 IL-4 和 IL-5，以及减少的 IL-2、IL-12 和 IFN-gamma。同样，与喂食不溶性纤维的小鼠相比，喂食可溶性纤维的小鼠的内毒素刺激的巨噬细胞显示出减少的 IL-1beta、TNF-alpha、IFN-gamma、IL-12 和硝酸盐，以及增加的 IL-1RA、精氨酸酶 1 和 Ym1。最后，喂食可溶性纤维为小鼠提供的行为保护在 IL-4 敲除小鼠中减少，并且可溶性纤维对 Con-A 刺激的脾细胞和内毒素激活的巨噬细胞的影响也减少。这些数据表明，富含可溶性纤维的饮食通过使 Th2 极化并促进巨噬细胞的替代激活来保护小鼠免受内毒素引起的疾病行为。
