大黄素对急性肺损伤的保护机制

Acute lung injury is one of the critical illnesses in internal medicine. Although comprehensive treatment measures have been taken, the mortality is up to 40%. The clinical use of rhubarb in the treatment of sepsis has made impressive achievements,but the research of rhubarb on acute lung injury was seldom. Our preliminary experiments confirmed that emodin can alleviate pulmonary edema and reduce rats mortality of septic acute lung injury,however the mechanism of emodin on acute lung injury still need to be clarified. Our research is divided into in vitro and in vivo study. In vivo part,the direct ALI model was copied by injecting LPS into tratracheal ,the indirect ALI model was copied by classic CLP(cecum ligation and puncture) method,the difference in the pathogenesis of two modeling ways was observed. Acute lung injury rats are intervented by emodin. We investigate the effects of emodin on inflammatory mediators,lung water metabolism(aquaporins, sodium channel、Na+-K+-ATP enzyme), AT-Ⅱ epithelial cells apoptosis,pulmonary surfactant-D and barrier function of intestine. And whether these effects changed with time are also been studied. In vitro part,we investigate the effects of emodin on inflammatory mediators、MAPKS signal transduction pathway of aquaporins and apoptosis of AT-II epithelial cells. We observe whether the mechanism of emodin on acute lung injury was different with different model. Our studies rich the protective mechanism of emodin on acute lung injury, provide experimental modern molecular biological basis for the basic TCM theory,for example: "disease of lung affecting large intestine""disease of large intestine affecting lung" , and also provide new ideas for TCM multiple targets for septic acute lung injury.

急性肺损伤是内科危重症，尽管采取综合治疗措施，病死率仍高达40％。临床用大黄治疗脓毒症取得了可喜的成果，但对其治疗急性肺损伤研究寥寥。我们的前期实验证实大黄素能减轻急性肺损伤大鼠的肺水肿程度，降低死亡率，但是对其作用机制缺乏进一步的研究。体内实验：分别用气管内注入LPS法和盲肠结扎穿孔法造成直接和间接肺损伤模型，观察两者在病机方面的差异；深入探讨大黄素对ALI大鼠炎性介质、肺水代谢（AQPs、ENaC和Na+-K+-ATP酶）、AT-Ⅱ凋亡和SP-D的作用、对肠道屏障功能的影响，且这些作用是否随时间而变化。体外实验探讨大黄素对大鼠肺泡Ⅱ型上皮细胞炎性介质、水通道蛋白MAPKS信号转导通路、细胞凋亡的影响。比较大黄素对不同模型作用机制是否有差异。从而完善大黄素治疗ALI的作用机制，为“肺病及肠”“肠病及肺”等中医基础理论提供现代分子生物学实验依据，也为中医药多靶点多途径治ALI提供新的思路。

急性肺损伤是内科危重症，尽管采取综合治疗措施，病死率仍高达40％。本研究比较两种经典造模方式：气管内注入LPS法和盲肠结扎穿孔法（CLP）造成直接和间接肺损伤模型，观察两者在病机方面的差异。研究发现：①两种造模方法出现严重症状时间不同：直接造模法是在造模后24h，而间接造模法是在造模后12h；②两种造模方法的致病机制不全相同：直接造模法：通过降低水通道蛋白AQP1、AQP5分泌及α/γ- ENaC功能，抑制肺水代谢，从而导致急性肺损伤发生；而间接造模法：则通过促使炎症反应细胞在肺组织中募集和活化，进一步产生趋化因子、氧自由基及蛋白酶等，抑制抑炎因子，导致炎症反应扩大，形成“瀑布”样连锁反应；同时抑制水通道蛋白AQP1和AQP5分泌及α/β/γ-ENaC功能、Na-K-ATP酶，抑制肺水代谢，导致急性肺损伤的出现。③大黄素针对两种造模方法治疗机制不同：直接造模法：大黄素主要针对造模后24h肺水代谢指标（AQP1和AQP5，α/γ- ENaC功能），改善急性肺损伤；而间接造模法：大黄素主要针对造模后12h炎症因子及抑炎因子，提高肺水代谢能力（AQP1、AQP5和α/γ- ENaC功能），改善急性肺损伤。④通过体外实验阐述其分子作用机制：在原代AT-II细胞实验中发现，在不同造模时间点，大黄素通过MAPK/ERK和MAPK/JNK通路抑制Caspase-3凋亡蛋白的表达；同时证实在不同的造模时间点，大黄素通过不同MAPK/ERK、MAPK/JNK和MAPK/P38通路抑制炎症因子，影响水通道蛋白（AQP1和AQP5）的生成。探索了大黄素治疗ALI的作用机制，为“肺病及肠”“肠病及肺”等中医基础理论提供现代分子生物学实验依据，也为中医药多靶点多途径治ALI提供新的思路。