磁共振TLR4成像探讨IBD发病机制及疾病活动度的研究

IBD is a chronic and non-specific inflammatory bowel disease. Toll-like recptores(TLRs)played a key role in pathogenesis of IBD.Current study planned to establish a new MRI-based TLR4 imaging approach to track the innate immune receptorTLR4 which was based on previous established methods in macrophage imaging.We will in vitro synthesize a TLR4 nano probe(Anti-TLR4-SPIO),detect its specificity,efficiency and TLR4-Ab activity in the probe.After that, we will apply the probe in the macrophage model to observe cell appopotosis.ICP-MS,Prussian-blue staining and TEM will be used to evaluate intra-celluar distribution of the nano probe.MRI was used to detect the probe conjugation efficiency.TLR4 probe was then injected into the acute and chronic IBD model,MRI was performed at various time points,then SI-time curve and R2 map was conducted, MR signal intensity and IBD clinical and pathology avtivity score was compared and correlation between TLR4expression and MR signal intensity was determined . Our study is hopeful to contribute to IBD clinical non-invasive diagnosis and IBD disease activity evaluation.

炎症性肠病（IBD）是一种常见的慢性非特异性肠道炎症性疾病，Toll样受体4(TLR4)在IBD的致病机制中起重要作用。本项目拟在前期建立MRI巨噬细胞成像的基础上，示踪细胞膜天然免疫受体TLR4, 建立靶向TLR4纳米探针示踪肠壁炎症的新技术，为临床IBD的诊断和治疗提供影像学依据。首先体外合成TLR4纳米探针（anti-TLR4-SPIO），检测其特异性、效价以及TLR4抗体活性后建立巨噬细胞模型，观察探针对细胞凋亡影响。通过电感耦合等离子质谱仪（ICP-MS）、普鲁士蓝染色和透视电镜等观察探针细胞内分布；MR检测探针细胞结合效价。最后将TLR4探针注入IBD 急慢性小鼠模型及正常小鼠，在不同时间点行MR成像，模拟信号强度-时间曲线及R2map，分析MR信号强度与临床／病理活评分与肠壁组织TLR4相关性。本研究有望为临床无创诊断及IBD疾病活动度评价提供新方法。

炎症性肠病（IBD）是一种常见的非特异性肠道炎症性疾病，Toll样受体4(TLR4)在IBD的致病机制中起重要作用。本课题组前期成功建立MRI巨噬细胞成像方法，本研究拟在此基础上，建立靶向TLR4纳米探针示踪肠壁炎症的新技术。首先合成TLR4纳米探针（anti-TLR4-SPIO），检测其特异性、3T MR成像弛豫性以及TLR4-Ab活性。随后建立巨噬细胞培养模型，以LPS刺激巨噬细胞后，分别加入100 ug Fe/ml的 anti-TLR4-SPIO（探针组）或未连接抗体的SPIO（对照组），观察探针对细胞凋亡影响；通过ICP-MS、普鲁士蓝染色和透视电镜等方法观察探针对细胞内铁含量及细胞内探针分布的影响；通过MR检测探针的效价。最后将TLR4探针通过尾静脉分别注入IBD 小鼠（DSS诱导）、TLR4敲除IBD小鼠以及正常小鼠，在不同时间点（0,4,24小时）行MR成像，模拟信号强度-时间曲线及R2map，分析MR信号强度与临床／病理活动度评分、肠组织TLR4表达量的相关性。本研究有望为临床无创性诊断及评价IBD疾病活动度提供新方法。