| Objective To investigate the effects of Dendrobium polysaccharide (DSP) on helper T (Th17)/regulatory T (Treg) cell balance and immune inflammation in collagen-induced arthritis (CIA) mice. Methods CIA mice were induced, and the model was identified by joint HE staining and morphological observation of the right hind paw. CIA mice were given 100, 200 and 300 mg/kg DSP intragastric treatment and divided into control group, model group, low DSP group, medium DSP group and high DSP group. HE staining was used to observe the pathological changes of the synovium of the right limb of mice in each group. Flow cytometry was used to detect the changes of Th17 cells, Treg cells and CD4+CD28-PD-1lowOX40+ T cells in spleen of mice in each group. The expression levels of IL-7 in the right knee joint of mice in each group were observed by immunohistochemistry, and the expression levels of IL-6 and IL-10 in serum and IL-6 and IL-10 in the right knee joint of mice in each group were detected by ELISA at different time points (0, 14, 28, 42 d). Results Compared with control group, the paw lesions of model group were aggravated; the synovial tissue pathological changes were obvious; the proportion of Th17 cells was increased; the positive expression of Foxp3 was decreased; the proportion of Treg cells and CD4+CD28-PD-1lowOX40+ T cells was decreased; the positive expression of IL-7 was increased, and the content of IL-6 was increased, IL-10 content decreased in serum and knee joint (all P<0.0.5). Compared with model group, the paw lesions of mice in low, medium and high concentration DSP groups were reduced; the synovial tissue pathological changes were improved; the proportion of Th17 cells decreased, the proportion of Treg cells and CD4+CD28-PD-1lowOX40+T cells increased, the positive expression of IL-7 decreased, the positive expression of Foxp3 increased.And the content of IL-6 decreased, IL-10 content increased in serum and knee joint (all P<0.0.5), and high concentration of DSP had the best effect. Conclusion DSP can regulate the balance of Th17/Treg cells in CIA mice, inhibit inflammation and alleviate pathological changes. |