基于imDC诱导T细胞免疫耐受研究芪葵颗粒干预1型糖尿病的作用机制

Enhancements on mature dendritic cells of antigen presenting cause T cell differentiation and imbalance, which destroyed the immunological tolerance, and result in autoimmune inflammation of islet β cells, that is the important pathogenesis of type 1 diabetes. Preliminary studies showed that Qikui granules significantly inhibited mature dendritic cells, reduced antigen presentation function, and increased inflammation suppression factor expression. However, the relationship between T cell immunological tolerance induced by immature dendritic cells in type 1 diabetes and Qikui granules remains to be further clarified. This study based on the process of nonobese diabetic mice with type 1 diabetes, uses Qikui granules intervention NOD mice with insulitis and type 1 diabetes, at the same time uses the immature dendritic cells induced by Qikui granules intervention naive T cells in vitro and NOD mice with insulitis and type 1 diabetes in vivo, observation of Qikui granules effects on T cell immunological tolerance. The research clarifies that the mechanism of Qikui granules inducing immature dendritic cells to restore balance of Th17/Treg and cause T cell clonal anergy, establishing immunological tolerance to prevention and treatment of type 1 diabetes. It has important scientific significance for using Chinese medicine on type 1 diabetes.

树突状细胞成熟后抗原提呈功能增强,致使T细胞分化失衡破坏了免疫耐受,引起胰岛β细胞自身免疫性炎症,是导致1型糖尿病发病的重要机制。前期研究表明芪葵颗粒能够抑制树突状细胞成熟,下调抗原提呈功能,增加抑炎因子表达,但芪葵颗粒与未成熟树突状细胞诱导的1型糖尿病T细胞免疫耐受之间的关系有待进一步阐明。本研究基于NOD小鼠1型糖尿病的发病过程,采用芪葵颗粒干预NOD小鼠胰岛炎及1型糖尿病模型;同时使用芪葵颗粒诱导的未成熟树突状细胞体外干预初始T细胞、体内干预NOD小鼠胰岛炎及1型糖尿病模型,观察芪葵颗粒对T细胞免疫耐受的影响。阐明芪葵颗粒通过形成未成熟树突状细胞,促进Th17/Treg恢复平衡及导致T细胞克隆无能,诱导免疫耐受,从而发挥预防和治疗1型糖尿病的作用机制。为中医益气治法应用于1型糖尿病的临床辅助治疗提供科学依据,为运用“治未病”理论预防1型糖尿病发病打下科学基础。

大量研究表明自身免疫调节异常是1型糖尿病（T1DM）的重要发病机制。树突状细胞(DC)破坏免疫耐受可导致胰岛炎症从而促使T1DM发病。免疫反应的类型取决于DC的成熟度。未成熟的DC具有通过促进Treg/Th17的平衡诱导免疫耐受的功能。初始T细胞增殖后分化成为效应T细胞和Treg，两种分化间的平衡对于维持免疫功能稳定至关重要。Th17分泌促炎细胞因子IL-17。IL-10是由Treg产生的抗炎细胞因子。课题组前期研究结果显示芪葵颗粒可影响显著减少小鼠骨髓来源DC，本项目中开展了芪葵颗粒干预NOD小鼠胰岛炎及1型糖尿病模型及芪葵颗粒诱导的未成熟树突状细胞体外干预初始T细胞、体内干预NOD小鼠胰岛炎及1型糖尿病模型的实验。研究结果显示芪葵颗粒给药可干扰NOD小鼠糖尿病发病，保护胰岛功能，并能抑制NOD小鼠及T1DM小鼠模型中DC细胞成熟，降低DC细胞抗原摄取的能力、DC刺激T细胞增殖能力，降低IL-2和IL-12的表达，增加NOD小鼠及T1DM小鼠模型中Treg/Th17比率，升高Foxp3、IL-10、降低IL-17。芪葵颗粒诱导的未成熟DCs能够在小鼠体内调节免疫系统，诱导T细胞向调节应T细胞分化，减少炎症攻击产生。研究证实芪葵颗粒能够抑制DC成熟，释放抑炎细胞因子IL-10，上调表达Foxp3，促进Treg细胞生成负性调控Th17细胞的生成和分化，调节Treg/Th17细胞平衡，并致T细胞克隆无能，从而诱导免疫耐受。研究为芪葵颗粒防治T1DM提供客观依据，具有重大科学意义。