Ganoderma lucidum polysaccharides reduce methotrexate-induced small intestinal damage in mice via induction of epithelial cell proliferation and migration

Aim: To study the effects of Ganoderma lucidum polysaccharides (Gl-PS) on methotrexate (MTX)-induced small intestinal damage in mice and the underlying mechanisms. Methods: BALB/c mice were used for in vivo study. The mice were administered with Gl-PS (50, 100, or 200 mg/kg, ig) for 10 d, and injected with MTX (50 mg/kg, ip) on d 7 and 8 to induce intestinal damage, and then sacrificed on d 11 for morphological study and tissue malondialdehyde (MDA) and superoxide dismutase (SOD) measurements. Before sacrificing, blood samples were collected to analyze immunoglobulin A (IgA). Rat intestinal IEC-6 cells were used for in vitro study. Cell proliferation and migration were assessed using MTT method and an in vitro wounding model, respectively. Transforming growth factor beta (TGF beta) protein expression was determined using ELISA assay. Ornithine decarboxylase (ODC) and c-Myc mRNA expression profiles were determined using RT-PCR. Results: MTX treatment caused severe mucosal damage, significantly increased small intestine MDA levels, and decreased SOD and serum IgA levels in BALB/c mice. Gl-PS (100 and 200 mg/kg) markedly reversed the MTX effects. In IEC-6 cells, Gl-PS (0.1, 1, and 10 mu g/mL) significantly stimulated the cell proliferation. Furthermore, Gl-PS (10 mu g/mL) significantly stimulated the cell migration. In addition, Gl-PS (10 and 20 mu g/mL) significantly increased the expression of ODC and c-Myc mRNAs. However, Gl-PS (up to 20 mu g/mL) had no effect on the expression of TGF beta protein. Conclusion: The results suggest that Gl-PS protects small intestine against MTX-induced injury via induction of epithelial cell proliferation and migration.