Dietary supplementation with American ginseng dietary fiber ameliorates intestinal mucosal barrier injury in immunosuppressed mice

Abstract

Dietary fiber is an important component of healthy eating patterns. Although American ginseng (Panax quiquefolium L.) is often used to improve body immunity, less attention has been paid to American ginseng dietary fiber (AGDF) in this regard. The aim of this study was to investigate the protective effect of AGDF on intestinal mucosal barrier injury induced by cyclophosphamide (CTX) in immunosuppressed mice and the underlying mechanism. The results showed that AGDF could increase immune organ index and enhance immunity of immunosuppressed mice, such as DTH response, lymphocyte transformation and proliferation and NK effector cell activity. At the same time, AGDF could restore the proportion of CD4+/CD8+ T lymphocytes induced by CTX to different extents, and promote the secretion of immunoglobulin IgG. More importantly, AGDF could up-regulate the contents of TNF-α, IFN-γ, IL-6 and IL-1β in serum and intestine of immunosuppressed mice, promote the secretion of cytokines and regulate the homeostasis balance between Th1/Th2 cytokines. It also upregulated the expression of tight junction proteins occludin, claudin-1 and ZO-1, and alleviated the degree of CTX-induced damage to the intestinal mucosal barrier. Meanwhile, AGDF could reduce intestinal epithelial cell apoptosis by activating TLR4/NF-κB signaling pathway, improving the phosphorylation of JNK and p38 signaling molecules, which may be the potential mechanism by which AGDF ameliorates intestinal mucosal injury in immunosuppressed mice. Therefore, AGDF may be used as a dietary supplement to prevent and treat intestinal mucosal barrier injury caused by CTX.