The effects of freeze-dried Ganoderma lucidum mycelia on a recurrent oral ulceration rat model

BACKGROUND: Conventional scientific studies had supported the use of polysaccharides and β-glucans from a number of fungi, including Ganoderma lucidum for the treatment of recurrent oral ulceration (ROU). Our aim of the present study was to evaluate whether freeze-dried powder from G. lucidum mycelia (FDPGLM) prevents ROU in rats. METHODS: A Sprague-Dawley (SD) rat model with ROU was established by autoantigen injection. The ROU rats were treated with three different dosages of FDPGLM and prednisone acetate (PA), and their effects were evaluated according to the clinical therapeutic evaluation indices of ROU. RESULTS: High-dose FDPGLM induced significantly prolonged total intervals and a reduction in the number of ulcers and ulcer areas, thereby indicating that the treatment was effective in preventing ROU. Enzyme-linked immunosorbent assay (ELISA) showed that high-dose FDPGLM significantly enhanced the serum transforming growth factor-β1 (TGF-β1) levels, whereas reduced those of interleukin-6 (IL-6) and interleukin-17 (IL-17). Flow cytometry (FCM) showed that the proportion of CD4(+) CD25(+) Foxp3(+) (forkhead box P3) regulatory T cells (Tregs) significantly increased by 1.5-fold in the high-dose FDPGLM group compared to that in the rat model group (P < 0.01). The application of middle- and high-dose FDPGLM also resulted in the upregulation of Foxp3 and downregulation of retinoid-related orphan receptor gamma t(RORγt) mRNA. CONCLUSION: High-dose FDPGLM possibly plays a role in ROU by promoting CD4(+) CD25(+) Foxp3(+) Treg and inhibiting T helper cell 17 differentiation. This study also shows that FDPGLM may be potentially used as a complementary and alternative medicine treatment scheme for ROU. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12906-017-2021-8) contains supplementary material, which is available to authorized users.