从肠道免疫角度探讨补肾强督治偻方调节强直性脊柱炎骨代谢机制

Abnormal bone metabolism is the main factor of disability in Ankylosing Spondilitis (AS). However, to date, there is no effective method to relieve or block it. Bushen-Qiangdu-Zhilv Decoction (BQZ) , which was established by Prof. Shu-De Jiao who is a well-known traditional Chinese medicine master in Rheumatology, has been demonstrated to be effective in relieving clinical symptoms, signs and inflammatory activity indicators of AS patients. Moreover, effects of BQZ on bone metabolism regulation and imaging improvement have also been reported. But the mechanism is unclear. Intestinal flora and IL-23 / Th17 axis interact and influence each other, which constitute a core part of intestinal immune mechanism and regulate the bone metabolism in AS. Based on the “intestinal flora- IL-23 / Th17 axis-bone metabolism” linear mechanism, we will firstly clarify the relationship between intestinal flora and IL-23 / Th17 axis in AS with cross-sectional study. Secondly, we will construct a modified AS animal model based on HLA-B27/β2 microglobulin transgenic rat. The effects of BQZ on bone metabolism through IL-23 / Th17 axis mediated-intestinal immune will be further examined. As IL-23/Th17 axis mediated-intestinal immune has a bridging role in intestinal flora and bone metabolism, we will explore the cellular signal transduction mechanism underlying BQZ regulation of the abnormal bone metabolism mediated by IL-23 / Th17 axis with further vitro study. These three researches are going to, to some extent, demonstrate the scientific connotation of anti-AS effects of the effective Chinese Medical formula by in-depth logic chains.

骨代谢异常是导致强直性脊柱炎（AS）患者残疾的重要因素，而西医治疗手段有限。名老中医焦树德教授的补肾强督治偻方治疗AS具有抗炎、调节骨代谢作用，可改善AS影像学进展，但具体机制不清。肠道菌群与IL-23/Th17炎症轴的相互作用构成了肠道免疫的核心机制，对AS骨代谢有调控作用。本研究沿着“肠道菌群—IL-23/Th17炎症轴—骨代谢”线性机制图，首先采用临床横断面研究筛选AS特异性肠道菌群，并验证其与IL-23/Th17炎症轴的关系；其次构建基于HLA-B27/β2-m双转基因的改良AS动物模型，体内实验探讨补肾强督治偻方通过肠道免疫调控AS骨代谢的作用机制；最后，鉴于IL-23/Th17炎症轴介导的肠道免疫对肠道菌群参与AS骨代谢调控的桥接作用，我们通过体外实验深入探讨补肾强督治偻方通过该轴调控骨代谢的信号转导机制。本研究通过递进深入的三个层次实验方案初步揭示中药复方治疗AS的科学内涵。

强直性脊柱炎(ankylosing spondylitis,AS)的西医治疗手段有限，而以全国名老中医焦树德教授的补肾强督治偻方为代表的中医药方案优势明显，但是中医治疗的科学内涵未阐明。鉴于IL-23/Th17炎症轴介导的肠道免疫对AS骨代谢的影响，新兴的肠道微生态研究为中药复方机制研究工作提供了新的契机。本研究沿着“肠道菌群—IL-23/Th17炎症轴—骨代谢”的线性机制图，开展补肾强督治偻方对AS骨代谢调节机制的研究，科学阐释该方治疗AS、改善AS影像学进展的科学内涵。本课题首先开展了AS肠道菌群的横断面研究，筛选出AS的特异性肠道菌群，结果显示Flavonifractor plautii可能是与AS密切相关的致病菌，且中药复方补肾强督治偻汤在一定程度上，可能有利于维持AS肠道菌群稳态，因为它没有增加机会致病菌C.bolteae的丰度。接着对该复方在既往的基础上进一步开展了质控研究，证实了该方质量的稳定性，为接下来的研究打下基础。我们在经典的AS动物模型—HLA-B27/β2-m双转基因大鼠模型的基础上通过腹腔注射人蛋白多糖（PG）、灌胃定植强直性脊柱炎特异性肠道菌群并在骶髂关节部位注射TNF-α的改良方法，构建AS动物模型。结果显示该模型能表现出AS的部分病理特点，包括尾部的僵直，双足关节的肿胀，X线亦可见关节的肿胀，其TNF-α水平高于空白组及非改良组。虽未见骨赘形成及关节的融合，但其临床症状的发生率较稳定，为AS的基础研究提供了一种新的造模方法。除了炎症表现外，异位骨形成和病理性骨破环是AS重要的病理环节。本课题通过实验证实了补肾强督治偻汤除了对IL-17/IL-23炎症轴的相关因子表达有抑制作用外，还对AS的骨代谢具有双向调节作用——既可以对骨质起到保护作用：a、对地塞米松破坏的成骨细胞有一定的保护作用，b、能抑制破骨细胞的分化；又能抑制体外培养的成骨细胞的分化，说明其对AS的异位骨形成有一定的抑制作用。为该复方治疗AS提供了新的科学依据。