2008-08-012024-05-18https://scholars.lib.ntu.edu.tw/handle/123456789/713535呼吸器設定不當會引起肺損傷、發炎以及機械訊息傳遞，亦即「呼吸器引發肺損傷」 (VILI)，其真正機轉仍不甚明確。細胞內促進發炎反應的訊息傳遞途徑已逐漸成為目前 研究主軸。吾人過去在動物VILI實驗模式中發現ACE 抑制劑的使用對VILI具有預防和 減輕之作用(Jerng JS et al. Thorax 2007; 62: 527- 35)。然而先前的研究均以動物個體主要 材料，難以得知肺臟中何種細胞組織受影響。故本計畫將以RAS為研究標的，探討在特 定肺臟的細胞種類受到不同程度的機械拉力作用受到的影響。本實驗計畫使用人類肺臟 組織中所含的細胞種類為研究材料，使用所建立的Flexcell細胞拉力系統作為引起傷害的 來源，經過一定時間的機械拉力後，分析細胞的各種基因表現和蛋白質活性的變化，以 瞭解RAS在VILI所扮演的角色。本研究計畫分三年進行：第一年計畫確立培養細胞的拉 力實驗系統，並以分子生物學的方法檢定細胞是否有發炎反應以及RAS系統的活化，以 及RAS各個基因表現的程度和angiotensin受體的表現；第二年將分析肺臟細胞受到 angiotensin處理後所引發的發炎反應，是否牽涉到主要的發炎路徑如NF-κB等並探討 RAS抑制劑是否可以抑制這些發炎反應；第三年將探討機械張力是否可能引發除了 NF-κB以外其他的發炎途徑，以及這些途徑是否和RAS有關。本計畫將針對RAS在機械 拉力所引起發炎的角色，進行深入的探討，以期釐清RAS在VILI的重要性。Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are one of the causes of acute respiratory failure. The pathogenesis of ALI/ARDS has been considered complex, but recently it has been shown that ventilation with inadequate setting may result in significant lung injury, so-called ventilator-induced lung injury (VILI). Although the exact mechanism for VILI remains to be elucidated, investigators have shown that induced lung inflammation is main etiology, especially for the nuclear factor-κB pathway. Recently, the involvement of the renin-angiotensin system (RAS) in acute lung injury has gained some interests. One of out recently published studies showed that polymorphism of the ACE gene affects the outcome of ARDS (Jerng JS et al. Critical Care Medicine 2006; 34: 1001- 6), suggesting that the RAS may be activated and play an important role in the pathogenesis as well as evolution of ALI/ARDS. Another one of our recent studies also showed that the RAS may be activated in the model of ventilator-induced lung injury, and the use of angiotensin-converting enzyme inhibitor may attenuate the development of lung injury. (Jerng JS et al, Thorax 2007; 62: 527- 35). Our findings suggest that the signaling pathway of angiotensin II may be important in the development of ALI/ARDS. However, the exact mechanism for the involvement of RAS in the development of VILI remains to be elucidated, especially about the question for the possible cell types responsible for the reaction to mechanical stretch. Therefore we propose for investigation with an in vitro cell stretch system. By using the commercialized Flexcell system, we will apply stretching force on cultured human cells of respiratory origin, and target at the RAS in these cell lines. In the first year, we will establish this in vitro cell stretch system, and confirm that the stretching induces a proinflammatory response of the cells; we will also assess the activity of the RAS in the cells. In the second year we will study the cellular reaction to the treatment with angiotensin, and compare it with the reaction to cyclic stretching. The study will focus on NF-κB, and whether blocking of RAS will attenuate the activation of NF-κB. In the third year we will focus on the signaling pathways other than NF-κB in response to cyclic stretching. We will also study the interaction of RAS with these pathways during cyclic stretching. By using molecular methods, we wish to elucidate the role of the rennin-angiotensin system in the development of ventilator-induced lung injury, and provide further evidence of the complex interaction between RAS and the intracellular signaling pathways.