Objective: To learn the mechanisms between gut microbiome and the autoimmunity benefits on Traditional Chinese Medicine (TCM) in central nervous system (CNS), we investigated the neuro-protection effects and gut mircobiota changes of Heshouwu () on experimental autoimmune encepha-lomyelitis (EAE), an animal model of multiple sclerosis (MS).
Methods: Mice were randomly divided into four groups: EAE mice (control phosphate-buffered saline group), 50 mg·kg·d Heshouwu ()-treated EAE mice, 100 mg·kg·d Heshouwu ()-treated EAE mice, and 200 mg·kg·d Heshouwu ()-treated EAE mice. The spinal cords were stained with hematoxylin and eosin (HE) and luxol fast blue for evaluating inflammatory infiltration and demyelination. The percentages of granulocyte macrophage-colony stimulating factor (GM-CSF)+CD4+, interleukin 17 (IL-17)+CD4+, Foxp3 CD4+, and interferon-γ (IFN-γ)+CD4+ T cells in the inguinal lymph nodes (LNs) and brain were determined by flow cytometry analysis. 16S rRNA gene sequencing was employed to analyze the changes in gut microbiota.
Results: We found that Heshouwu () alleviated the disease severity and neuropathology of EAE as evaluated by clinical and histopathologyical scores. Heshouwu () increased the diversity and abundance of the gut microbiota, and decreased / ratio (F/B ratio). Heshouwu () also decreased the concentrations of IL-10, and IL-21 and increase the levels of GM-CSF, IL-17A, IL-17F and IL-22 in serum of EAE mice. Moreover, Heshouwu () modulated the T cell responses by inhibiting Th17 cells and restoring Treg cells in the small intestine lymphoid tissues and inguinal lymph nodes. Microbiota-depleted mice receiving Heshouwu ()-treated fecal microbiota trans-plantation had lower disease severity, neuropathology scores and alleviation of Th17/Treg imbalance compared to ad libitum group.
Conclusions: Our findings suggested that the vital neuro-protection role of Heshouwu () (TCM) in immunomodulation effects partly by regulations of gut microbiome.
Keywords: Heshouwu (Radix Polygoni Multiflori); T cell response; encephalomyelitis, autoimmune, experimental; gastrointestinal microbiome.