| Inflammatory bowel disease (IBD) is a kind of chronic, nonspecific, inflammatory intestinal diseases, including ulcerative colitis and Crohn’s disease. The treatments of IBD have limitations with efficiency and side effects. CD103+CX3CR1-DC and CD103-CX3CR1+ DC are two main types in intestinal lamina propria dendritic cells. Astilbin is one of the main monomer component of Smilax. Our previous work demonstrated that astilbin suppressed the onset and severity of colitis in mice treated with DSS, promoted the expression of CD103a+ DC and raised regulatory T cells on DSS-induced colitis in mice. This study was planned to further explore influence of astilbin on activity of intestinal CD103+ DC and its molecular mechanisms.[Aims]Observing the distribution of CD103a+DC in spleen and intestinal of DSS-induced colitis mice, after treated with tastilbin. Detecting whether astilbin can modulate function of CD103a+ DC, enhance number of Tregs. To explore the molecular mechanisms of astilbin regulating activity of CD 103a+DC to induce regulatory T cells preliminary.[Methods]The mouse model of DSS-induced colitis was established to analysis the the frequency and correlation of CD103a+ DCs, Tregs in spleen and intestines by flow cytometry depending on astilbin treated or not. The expression of (B7H1, CD86, IL-15R) and the secretion of (IL-10, TGF-β, IL-12, IL-6, IL-1β, TNF-α) of CD103a+ DC were analyzed by flow cytometry. Different concentrations of astilbin were added on splenocyte in vitro. The cytokines of CD103a+ DC were analyzed by flow cytometry. Isolate CD103a+ DC by Flow cytometry stimulated with different concentrations of astilbin in vitro, the levels of cytokines were detected by flow cytometry, Supernatant of cell cytokine levels were detected by ELISA. After astilbin treatment, CD103+ DC, CD103a- DC were cocultured with splenic CD4+T cells, and levels of CD4+ CD25+ Foxp3+ T cells were then detected. The expression of phosphorylated STAT3 antibody pY705, pS727 of SGC-7901 and CD103a+ DC, CD103a- DC stimulated with astilbin were analyzed by flow cytometry and Western Blot. According to stimulated with STAT3 inhibitor and astilbin. The levels of CD 103a+DC, CD 103 a- DC cytokine secretion were detected by flow cytometry.[Results]The frequency of CD103a+ DCs in spleen and intestine of DSS-induced mice were significantly enhanced. Astilbin treatment enhanced frequencies of CD11c+CD103a+ DC and Treg cells (CD4+CD25+CD127-) in inflamed intestine of DSS-induced colitis. Astilbin modulates function of CD103+ DC in DSS-induced colitis. Astilbin treatment resulted in an up-regulation of B7H1, IL-10, TGF-p, down-regulation of IL-12, IL-6, IL-1β, and no variations on CD86, IL-15Ra, TNF-a. Different concentrations of astilbin were added into splenic cells.The cytokines of CD 103a+ dendritic cells were significantly increased in a dose-dependent manner. Astilbin increased B7H1 expression of purified CD103a+ DC and enhanced the production of splenic cell culture supernatant IL-10, TGF-β with a dose dependent manner and no variations of CD86. While no significant change in expression of CD 103a- DC happened. Astilbin treated CD103a+ DC cocultured with CD4+CD25+Foxp3+ T cells for 48h, but levels of CD4+CD25+Foxp3+T cells were significantly enhanced, while CD 103a- DC is not so obviously. Astilbin strongly activates STAT3 phosphorylation in SGC7901 cells and purified CD103a+DC on pY705 and pS727. However, CD 103a- DC had no significant difference. Astilbin induces regulatory function of CD 103 a+DC dependent on the STAT3 signaling. Compared with STAT3 inhibitor group, the difference between levels of CD103a+ DC, CD103a- DC stimulated with astilbin cytokine secretion can be ignored.[Conclusions]Preliminary results shows that astilbin possess protective effect of DSS-induced colitis through modulates function of CD103a+DC to induce regulatory T cells via the STAT3 signaling. |
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