Polysaccharide from natural Cordyceps sinensis ameliorated intestinal injury and enhanced antioxidant activity in immunosuppressed mice

Polysaccharide is one of the main bioactive substances in Cordyceps sinensis (C. sinensis). The aim of this study was to investigate the effect of polysaccharide from natural C. sinensis (CSP) on intestinal mucosal immunity and antioxidant activity in cyclophosphamide (Cy)-induced intestinal immunosuppressed mice, further to explore the potential mechanism. Results showed that in mice with Cy-induced intestinal injury, the supplement of CSP (25, 50, 100 mg/kg.bw) significantly increased the levels of goblet cells and mucus in intestine in a dose-dependent manner. The formation of immunoglobulin A (IgA)-secreting cells and the secretory IgA (sIgA) contents were promoted obviously in CSP groups. Furthermore, CSP significantly promoted the secretion or mRNA expression of T helper (Th) 1 style cytokines, including interleukin-2 (IL-2), IL-12 p40, interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha), in addition to Th1 style transcription factor T-bet. Besides, the levels of Th2 style cytokines, including IL-4, IL-10 and transcription factor GATA-3, were also improved. The value of T-bet/GATA-3, as well as IFN-gamma/IL-4 was increased obviously. These results indicated that CSP effectively enhanced intestinal mucosal immunity and regulated polarization of Th1/Th2 cells. The total antioxidant capacity (T-AOC), and the activities of superoxidase dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) in liver were increased significantly, and the content of malondialdehyde (MDA) was decreased dose-dependently. In conclusion, CSP effectively ameliorated Cy-induced intestinal injury in mice, which provided a good suggestion of the potential utilization of CSP as a natural immunopotentiator and antioxidant.