Abstract. Gloeostereum incarnatum, a precious edible mushroom, displays anti-bacterial and anti-inflammatory activities; however, its immunomodulatory effect has not been studied yet. The present study aimed to investigate whether polysaccharide compositions of G. incarnatum polysaccharides (GIPS) possess immunomodulatory and immuno-enhancing effects in a Cyclophosphamide monohydrate (CTX)-induced BALB/c mice model. The 28-day GIPS administration at doses of 0.1, 0.3 and 0.9 g/kg remarkably reversed the bodyweight loss, increased the thymic index and promoted T lymphocyte proliferation in CTX-induced immunosuppressed mice. GIPS significantly raised the serum levels of immunoglobulin (Ig) A and IgG, promoted the production of interleukins (ILs), including IL-2, IL-3 and IL-6, interferons, including interferon (IFN)-α and IFN-γ, and monocyte chemotactic protein 1 in the spleen, which resulted in accelerating recovery of immunosuppression. Finally, GIPS showed anti-oxidative effects indicated by the increased superoxide dismutase levels in the serum and spleen, and the reduced level of reactive oxygen species in the spleen. The results of the current study demonstrated that GIPS positively adjusts the immune system, which may serve as a potential immunostimulatory agent.
IntroductionThe immune system, a complex self-regulation system, is responsible for the defense function of organism to prevent outside pathogens, remove the waste material and maintain the monitoring function for malignant cells (1). The immune system is highly sensitive (2), and shows impaired immune responsiveness to pathogen invasion, during which, immune cells are activated and secret pro-inflammatory mediators including interleukins (ILs) and interferons (INFs) are increased (3,4). And immunity closely related to oxidative stress, which could lead to aberrant expression of inflammatory cytokines and chemokines (5). Cyclophosphamide monohydrate (CTX), a cancer chemotherapeutic agent, facilitates cell apoptosis and decreases the homeostatic proliferation of regulatory T cells (6), which has been widely used in the establishment of immunosuppressive animal models (7-9).Previous researchers focus their studies on searching immunomodulatory agents for years (10). However, the drugs performed in clinic, especially single-component chemicals, display severe adverse effects including general malaise and/or neurotoxicity (11,12), which is hard to meet the requirements of immunosuppressive patients. Dietary polysaccharides from natural products are getting more attention due to their health benefits and low toxicity (13,14), which have been confirmed to exhibit multiple immunomodulatory effects (15,16). Gloeostereum incarnatum, a precious edible mushroom, parasitizes broad-leaved wood in northern Japan and northern China (17). Traditionally, G. incarnatum preparation is widely used for the treatment for enteritis, dysentery and gastric ulcer (18). Polysaccharides obtained from G. incarnatum fruiting body have been reported to possess anti-tumor and ant...