水通道蛋白在脂肪栓塞综合征发病过程中的作用及机制

Fat embolism syndrome (FES) is usually characterized by hypoxia due to actue lung injury, with rapid progress and high mortality. Pulmonary edema is predominantly pathological demonstration in this disease, which suggests the dysfunction of water transfer in the lung. Some studies have showed that aquaporins play an important role in balancing pulmonary water. Our pilot experiment also demonstrated that the expression of aquaporins decreased in the lung after fat was intravenously injected and they came back when the rats recovered. Therefore we hypothesize that aquaporins might play a key role in the pathological process of FES. The contents of this study are listed as follow:(1)To observe the changes of pulmonary aquaporin-1,3,4,5 in FES model in rats;(2) To measure the level of aquaporin-1,3,4,5 in cultured pumonary microvascular endothelial cells, bronchial epithelial cells and type II alveolar epithelial cells after they are incubated with free fatty acids and to observe the effect of up-regulating and down-regulating of each aquaporin on damage degree of cells cultured with fatty acids;(3) By inhibitting the main routines of MAPK signaling pathway, we intend to illustrate the intracellular signaling pathways of the aquaporin-1 in pulmonary microvascular endothelial cells which are co-cultured with fatty acids; (4) To observe the effect of suppressing or enhancing of quaporin on the lung injury and on the mortality in FES model in rats. The objective of this study is to illustrate the role of aquaporin in the pathological process of FES, and so to provide a new thought for the future treatment of FES.

脂肪栓塞综合征（FES）发病凶险，死亡率高。肺是FES最易受累的器官，其主要病理变化是严重水肿，提示肺水转运发生了障碍。已有研究表明水通道蛋白(AQPs)是维持肺水平衡的重要机制。我们预实验研究显示大鼠FES时肺组织AQPs表达减少，随病情改善，表达恢复。因此我们假设在FES的病理机制中AQPs起重要作用。本研究:(1)测定大鼠FES时AQP1、3、4、5在肺组织中的表达变化；(2) 观察体外培养的大鼠肺微血管内皮细胞、支气管上皮细胞和肺泡II型上皮细胞经脂肪酸处理后AQPs的表达变化及改变AQP各亚型表达能否影响脂肪酸的致伤程度；（3）分别阻断MAPK通路的主要途径，探讨脂肪酸引起肺微血管内皮细胞AQP1变化的细胞内信号转导通路；(4) 在FES大鼠模型中观察抑制和增强AQPs功能对大鼠死亡率和肺损伤的影响。本课题旨在明确AQPs在FES发病机理中的作用，从而为FES的治疗提供新的思路。

脂肪栓塞综合征（FES) 是脂肪未经过机体或体外乳化处理而直接进入循环造成的危象，其致病机制尚不明确，尚无特异性疗法。动物实验显示，脂肪栓塞综合征在肺部引起的主要病理变化是严重肺水肿，提示肺部的液体转运出现了障碍。水通道蛋白（AQP）是一种顺渗透梯度、双向性跨膜运输水分子的通道蛋白。水通道蛋白1 (AQP1)主要表达于肺微血管内皮细胞, 它在微血管内皮与肺泡上皮之间的水转运过程中起着重要作用。我们假设AQP1参与了脂肪栓塞综合征中肺部的液体转运和肺水肿的形成。本研究中（1）在尾静脉注射同种异体脂肪建立小鼠脂肪栓塞模型，观察脂肪栓塞模型中肺水肿的发展过程并检测肺组织内AQP1的表达变化；（2）探究脂肪栓塞综合征中AQP1的表达改变是否与FES中释放的游离脂肪酸(FFA)有关，我们在体外实验中研究游离脂肪酸对大鼠肺微血管内皮细胞中水通道蛋白1的表达影响。