溃疡性结肠炎（UC）是一种发病机制尚未明确的直结肠慢性非特异性炎症性疾病。研究发现淋巴细胞肠道归巢在UC发病中有重要作用，而维生素D（VD）能抑制其归巢，因此VD及其受体信号途径可能是治疗的关键环节。UC患者常伴有低VD血症，但补充常规剂量VD疗效不明显，而动物实验表明大剂量VD具有免疫抑制作用，但也存在高血钙等副作用。前期研究发现和肠饮治疗UC可以减轻症状、减少复发；并能减少局部淋巴细胞浸润、降低整合素β7、增加VD受体表达。有研究发现在结肠、淋巴结、脾等部位存在1α羟化酶，可将25(OH)D3转化为具有生物活性的1,25(OH)2D3。我们推测和肠饮可能通过调控局部VD的合成及其受体信号通路影响淋巴细胞肠道归巢，减轻肠道损伤。因此，项目组通过UC模型研究VD调控的淋巴细胞肠道归巢在疾病中的作用及和肠饮的干预作用，并通过细胞实验明确其分子机制，为进一步研究UC发病机制、中医治疗提供基础。

Ulcerative colitis (UC) is a not yet clear to the pathogenesis of the rectum and colon, chronic non-specific inflammatory diseases. The study found that lymphocyte intestinal homing plays an important role in the pathogenesis of UC, and vitamin D (VD) can inhibit it. Thus VD and its receptor signaling pathway may be the key to the treatment. Clinical study found that UC patients often accompanied by low VD, but regular doses of VD supplements do not have a significant effect on the disease. However, animal experiments show that large doses of VD has immunosuppressive effects, but there are side effects such as hypercalcemia. Our clinical studies have found Hechang Yin in the treatment of UC can reduce symptoms and reduce recurrence, and animal experiments also show that it can reduce local lymphocytic infiltration, reduce β7 integrin and increase expression of VD receptors. Studies have found that in the colon, lymph nodes, it presence 1α-hydroxylase, which can convert 25(OH)D3 to 1,25(OH)2D3 a biologically active. We speculate that Hechang Yin relieves intestinal injury by regulating the local synthesis of VD and VD receptor signaling pathway thereby affecting the intestinal lymphocyte homing. Therefore, VD mediated intestinal lymphocyte homing and Intervention of Hechang Yin in UC will be researched, and its molecular mechanism will be clarified by cell experiments. It will provide research bases for further study of the pathogenesis of UC and TCM therapy.