基于“肠-肾”轴探讨益肾汤经结肠透析调控SIRT6/NF-κB信号通路改善CRF肠粘膜屏障损伤的机制研究

Chronic renal failure (CRF) is the leading cause of death in its patients. It is of important significance on prevention and treatment of CRF. Colonic dialysis can reduce toxin levels, which shows protective effect on intestinal mucosal barrier and improvement on the quality of life in the patients. Since 1996, we have carried out a series of studies to explore therapeutic effect of Yishen Decoction on CRF by the method of colonic dialysis, and been funded by grant from the national natural science foundation of China. Our previous studies showed that the treatment could inhibit inflammation to improve intestinal mucosal barrier injury induced by uremia toxin. Recent studies have confirmed that the "gut - kidney" axis is the key mechanism in the pathogenesis of CRF, and intestinal mucosal barrier injury is a potential target for the treatment. It had been reported SIRT6 could improve impaired autophagy and inflammation by regulating the expression of NF-κB, which is expected to be therapeutic targets of intestinal mucosal barrier injury in CRF. We hypothesize that the treatment can regulate SIRT6/NF-κB signaling pathway to ameliorate inflammation and impaired autophagy in intestinal mucosal barrier injury of CRF, which is based on the "gut - kidney" axis theory and "inflammation and impaired autophagy" as a new target. We will investigate the effect of the treatment on expression of genes and proteins of autophagy pathway in enterocyte and definite the molecular mechanisms of the treatment on alleviating intestinal mucosal barrier injury in CRF, which involves regulating SIRT6/NF-κB signaling pathway to inhibit inflammation and improve impaired autophagy.

慢性肾衰竭（CRF）是导致患者死亡的主要原因，积极防治意义重大。结肠透析可降低毒素水平，保护肠粘膜屏障，提高生存质量。课题组从96年即展开益肾汤经结肠透析治疗的系列研究，获包括国自然在内的多项基金资助。前期研究发现该治疗可通过抑制炎症改善尿毒症毒素诱导的肠粘膜屏障损伤。近期研究证明“肠-肾”轴是CRF发病机制过程中的核心环节；肠粘膜屏障损伤是其治疗的潜在靶点；SIRT6可通过调节NF-κB的表达，发挥抗炎改善自噬的作用，有望成为CRF肠粘膜屏障损伤防治的切入点。基于此，本研究拟提出“该治疗通过调控SIRT6/NF-κB信号通路，抑制炎症，改善自噬障碍，减轻CRF肠粘膜屏障损伤”的假说，以“肠-肾”轴为理论，“炎症与自噬障碍”为新靶点。观察其对肠上皮细胞自噬信号通路相关基因和蛋白表达的影响，明确其干预SIRT6/NF-κB信号通路、抑制炎症、改善自噬障碍，减轻CRF肠粘膜屏障损伤的分子机制。

慢性肾衰竭（CRF）是各种慢性肾脏病持续进展的共同结局，已经成为全球性的公共健康问题，积极防治意义重大。近来的研究表明，结肠是产生尿毒症毒素的重要器官，所产生的多种尿毒症毒素，不仅加剧CRF进展，而且是患者死亡的重要病因，其主要病理改变--肠粘膜屏障损伤，业已成为CRF治疗的关键靶点，发病机制涉及炎症与自噬障碍。中药经结肠透析是通过肠道途径增加尿毒症毒素排出，对于延缓CRF进展虽具有显著的疗效，但其具体机制尚未明确。近年研究显示，SIRT6为沉默信息调节因子基因家族Sirtuins成员，可通过调节NF-κB的表达，发挥抗炎改善自噬的作用，有望成为CRF肠粘膜屏障损伤防治的切入点。.课题组从1996年已经着手益肾汤经结肠透析治疗的系列研究，前期研究显示，益肾汤经结肠透析治疗除发挥清除毒素的作用外，也可以维持机体免疫平衡，调节机体的微炎症状态。本课题通过建立CRF大鼠动物模型，采用益肾汤经结肠透析干预CRF大鼠，结果显示，益肾汤经结肠透析可改善CRF大鼠肾功能及肾脏病理损害，机制与调控SIRT6/NF-κB信号通路，抑制炎症因子表达，改善自噬障碍，减轻CRF肠粘膜屏障损伤有关。体外培养人结肠上皮细胞（T84），采用尿素刺激，诱导肠上皮细胞损伤，给予自噬激活剂及抑制剂、SIRT6激活剂及抑制剂干预，结果显示，尿素刺激可诱导结肠上皮细胞紧密连接蛋白表达下降、细胞发生炎症反应和自噬障碍，上调SIRT6/NF-κB信号通路，可抑制炎症反应，改善自噬障碍，减轻尿素诱导的肠粘膜屏障损伤。进一步给予益肾汤经结肠透析含药血清干预，结果显示，益肾汤经结肠透析含药血清可上调SIRT6/NF-κB信号通路，抑制炎症反应，改善自噬障碍，减轻尿素诱导的肠粘膜屏障损伤。.综上，本项目明确了益肾汤经结肠透析可调控SIRT6/NF-κB信号通路，抑制炎症反应，改善自噬障碍，减轻CRF肠粘膜屏障损伤，有效延缓CRF疾病进展，为中西医结合防治CRF提供依据。