大黄素调节内质网应激介导的NLRP3活化对重症急性胰腺炎所致肺损伤的干预机制研究

Acute pancreatitis (AP) is a potentially lethal inflammatory disease. Systemic inflammatory response syndrome (SIRS) and multiple organ dysfunction syndrome (MODS) are attributed to the severe acute pancreatitis (SAP). Acute lung injury (ALI) is the most common serious complication of SAP patients, and subsequent acute respiratory distress syndrome (ARDS) is the leading cause of death. In control of lung tissue inflammation is an important direction to improve the survival rate of ALI caused by SAP. According to the previous researches, the occurrence of acute pancreatitis associated lung injury (APALI) may be mediated by the activated NLRP3 inflammasome which is induced by endoplasmic reticulum stress. In addition, the down-regulation of aquaporin is correlated to the activation of NLRP3, and endoplasmic reticulum stress process and the NLRP3 inflammasome activation are inhibited by traditional Chinese medicine active ingredient emodin in diverse inflammatory diseases, including AP. However, the effect of emodin and NLRP3 in APALI remains to be elucidated. In our previous studies we have found that emodin has protective and anti-inflammatory effects on APALI. Our work also have demonstrated that the expression of AQP1 and AQP5, which are most important aquaporin factors in respect of regulating the transportation of water on both sides of the cell membrane, are up-regulated in the course of APALI. Finally, we hypothesize that emodin functions by regulating the endoplasmic reticulum stress and NLRP3 inflammatory body activation in the treatment of APALI. The model of rats with APALI is created for the study of endoplasmic reticulum stress, mitochondrial damage and NLRP3 activation which are the main mechanisms of APALI. Then we will analyze the effect of emodin on the activation of NLRP3 and the related underlying molecular mechanisms. We hope that our study provide a new idea and target for the prevention and treatment of APALI.

急性肺损伤（ALI）是重症急性胰腺炎（SAP）患者最常见的严重并发症，控制肺组织炎症反应是提高SAP所致ALI生存率的重要方向。研究指出NLRP3炎症小体活化可能介导了APALI的发生，内质网应激能够诱导NLRP3炎症小体活化，水通道蛋白（AQP）的封闭或下调也与NLRP3激活有关；而中药活性成分大黄素对内质网应激过程以及NLRP3炎症小体活化均具有抑制作用，申请人前期研究发现大黄素对APALI具有保护及抗炎作用，其过程伴随AQP1及AQP5的表达上调，推测大黄素可能通过内质网应激/NLRP3炎症小体活化途径在APALI治疗中发挥调节机制。本课题计划利用大鼠重症胰腺炎肺损伤模型阐述内质网过度应激、线粒体损伤、NLRP3炎症小体活化是APALI发生的主要机制，并分析大黄素对内质网应激/NLRP3炎症小体活化途径的影响以及相关分子机制，为APALI的防治提供新思路及作用靶点。

急性肺损伤（ALI)是重症急性胰腺炎（SAP）患者的严重并发症，探究急性胰腺炎肺损伤的发生机制会为治疗提供有效的靶点。中药在急性胰腺炎肺损伤临床治疗中有明确的疗效，但具体机制并不明确。因此，明确SAP致ALI的致病机制及中药的治疗靶点对降低胰腺炎肺损伤死亡率具有重要意义。我们通过建立大鼠急性胰腺炎肺损伤模型和肺泡上皮细胞培养两个层面，观察内质网应激、氧化应激、线粒体损伤、细胞凋亡以及NLRP3炎症小体活化等情况，同时设置内质网应激抑制剂及内质网应激激活剂干预组、大黄素干预组，证实了大黄素通过调控肺泡上皮细胞内质网应激、线粒体损伤及NLRP3炎症小体活化减轻急性胰腺炎大鼠肺损伤。同时我们通过体内实验证明大黄素通过激活Nrf2/HO-1通路并抑制NLRP3炎症小体活化，进而减轻大鼠急性胰腺炎肺损伤；体外实验证明大黄素通过激活Nrf2/HO-1通路，抑制NLRP3炎症小体活化，进而抑制LPS诱导的大鼠肺泡上皮L2细胞损伤。以上结果提示大黄素通过激活Nrf2抑制NLPR3炎症小体活化发挥对急性胰腺炎的治疗作用大，此结果不仅为大黄素合理应用提理论依据，还可为临床开发其他潜在有效药物提供新的分子靶点。最新研究表明，NLRP3炎症小体是铁死亡的关键分子，我们推测铁死亡在急性胰腺炎肺损伤过程发挥巨大作用。接下来我们继续建立大鼠AP模型，并且给予焦亡抑制剂以及铁死亡抑制剂腹腔注射，结果发现抑制细胞焦亡、铁死亡可缓解胰腺炎大鼠疾病进程；中药成分Wedelolactone进行治疗干预处理后，可抑制AP大鼠细胞焦亡、铁死亡。从细胞水平我们也证实了Wedelolactone对胰腺细胞铁死亡同样具有抑制作用。在作用机制方面，我们发现Wedelolactone在转录水平调控GPX4表达缓解Caerulein诱导的胰腺细胞损伤，提示GPX4可能为治疗急性胰腺炎肺损伤潜在调节分子，为后续研究提供新的视角。