Polysaccharides are important pharmacologically active substances found in the perennial orchid Dendrobium huoshanense. In the present study, we sought to determine whether antioxidant and anti-inflammatory mechanisms were involved in Dendrobium huoshanense polysaccharides (DHPs)-mediated protection from D-galactose-induced intestine injury in an aging rat model. The effects of DHPs on ileal antioxidant capacity, mucosal barrier integrity and the inflammatory response were investigated in D-galactose-treated rats. The results showed that DHP administration largely attenuated the D-galactose-induced malondialdehyde (MDA), interleukin (IL)-6, tumor necrosis factor (TNF)-a, IL-4, IL-10, Toll-like receptor four and NF-jBp65 content increases and also markedly renewed the total antioxidant capacity and the claudin and occludin contents of ileal tissues from the D-galactose-treated rats. We also found that DHP more markedly affected the IL-6 and TNF-a levels than it did the IL-4 and IL-10 levels in the ileal tissues from the D-galactose-treated rats. These results suggest that DHPs can protect the rat ileum from D-galactose-induced injury by attenuating lipid peroxidation, improving antioxidant capacity and mucosal barrier integrity, correcting imbalanced inflammatory cytokine networks and suppressing the inflammatory response. The novel insights into the mechanism involved in DHPs protection of ileal health in our D-galactose-induced aging model rat advances current understanding of the aging process.

To discuss the molecular mechanism of immunoenhancing activities of Hyriopsis cumingii polysaccharides (HCPS), influences of HCPS on mice immunosignaling molecules (IL-2, IL-10, IFN-γ, NO, cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP)) and T lymphocyte differentiation (to CD4 + and CD8+ T cells) were evaluated by cell model in vitro and/or cyclophosphamide-induced immunosuppression animal model in vivo. Results showed that gastric gavage of crude HCPS could promote the production of IL-2, IFN-γ, inducible nitric oxide synthase (iNOS), cGMP, CD4 and CD8 in a dose-dependent manner. While, crude HCPS by gastric gavage exhibited suppressive effects on the production of IL-10 and cAMP in a dose-dependent manner. Crude HCPS and its purified fractions (HCPS-1, HCPS-2 and HCPS-3) could strengthen peritoneal macrophage expressing iNOS in vitro in a dose-dependent manner. HCPS-stimulated immunostrengthening functions was mediated, at least in part, by immunosignaling molecules of IL-2, IL-10, IFN-γ, NO, cAMP and cGMP, and T lymphocyte differentiation (to CD4+ and CD8+ T cells). ARTICLE HISTORY

To discuss the molecular mechanism of immunoenhancing activities of Hyriopsis cumingii polysaccharides (HCPS), effects of HCPS on mice immunologic receptors (toll-like receptors-4 [TLR-4] and mannose receptor-1 [MR-1]), transcription factor (nuclear factor kappa-B [NF-κB]), and cytokines (interleukin-6 [IL-6] and tumor necrosis factor-α [TNF-α]) were evaluated by cell model in vitro and cyclophosphamide-induced immunosuppression animal model in vivo. Results showed that HCPS could promote the mRNA synthesis of TLR-4, MR-1, IL-6, and TNF-α in spleen, and the gene expression of TLR-4, MR-1, NF-κB, IL-6, and TNF-α in spleen and serum in a dose-dependent manner. Crude HCPS and its purified fractions (HCPS-1, HCPS-2, and HCPS-3) could strengthen peritoneal macrophage expressing MR-1 and NF-κB in a dose-dependent manner. In addition, HCPS-3 showed stronger promotions on MR-1 and NF-κB than crude HCPS, HCPS-1, and HCPS-2. It suggested that HCPS-stimulated immunostrengthening was mediated, at least in part, by TLR-4/NF-κB/IL-6 and TLR-4/NF-κB/ TNF-α signaling pathways. MR-1, IL-6, and TNF-α might be 3 of the immune regulators mediating immunity and homeostasis when HCPS performed immunoenhancing activities.

Anti-angiogenic activities of crude Hyriopsis cumingii polysaccharides (HCPS) and its purified fractions (HCPS-1, HCPS-2 and HCPS-3) were evaluated in vivo using the chicken embryo chorioallantoic membrane (CAM) assay. The promoting effects of crude HCPS and its purified fractions on the chemotaxis, proliferation and phagocytosis of peritoneal macrophage were tested by cell model in vitro and cyclophosphamide-induced immuno-suppression animal model in vivo. The results showed that HCPS could significantly suppress the neovascularization of chicken embryo CAM and promote peritoneal macrophage migrating to monocyte chemotactic protein-1 (MCP-1), propagating and devouring sheep red blood cell (SRBC) in a dose-dependent manner. In addition, HCPS-3 showed stronger immunostimulatory activities in vitro than crude HCPS, HCPS-1 and HCPS-2. The beneficial effects of HCPS on the immune system might be, at least in part, attributed to the improvement of chemotaxis, proliferation and phagocytosis of peritoneal macrophage. All these results suggest that HCPS is a potential immunoenhancing and anti-tumor agent.