Department of General Surgery, Shaanxi Provincial People's Hospital, Xi'an, Shaanxi, 710068, People's Republic of China.
Inflammation. 2024 Feb;47(1):376-389. doi: 10.1007/s10753-023-01916-0. Epub 2023 Oct 29.
Intestinal ischemia‒reperfusion (I/R) injury is a common pathological process in patients undergoing gastrointestinal surgery, leading to local intestinal damage and increased microvascular permeability, eventually causing extraintestinal multiple organ dysfunction or sepsis. The NLRP3-mediated inflammatory response is associated with I/R injury. Methane saline (MS) has anti-pyroptosis properties. This study aims to explore the protective effect of MS on intestinal I/R injury and its potential mechanisms. After MS pretreatment, the in vivo model was established by temporarily clipping the mouse superior mesentery artery with a noninvasive vascular clamp, and the in vitro model was established by OGD/R on Caco-2 cells. The results of HE and TUNEL staining showed intestinal barrier damage after I/R injury, which was consistent with the IHC staining results of tight junction proteins. Moreover, the expression of the NLRP3 signaling pathway was increased after I/R injury, and inhibition of NLRP3 activation reduced Caco-2 cell injury, indicating that NLRP3-mediated pyroptosis was one of the main forms of cell death after I/R injury. Subsequently, we found that MS treatment ameliorated intestinal barrier function after I/R injury by suppressing NLRP3-mediated pyroptosis. MS treatment also reduced mitochondria-associated membrane (MAM) formation, which was considered to be a platform for activation of the NLRP3 inflammasome. Importantly, MS reduced ER stress, which was related to the PERK signaling pathway. Knocking down PERK, a key protein involved in ER stress and MAM formation, reversed the protective effect of MS, indicating that MS suppressed NLRP3 by reducing ER stress and MAM formation. In conclusion, we believe that MS suppresses MAMs and activation of the NLRP3 inflammasome by regulating the PERK signaling pathway to ameliorate intestinal I/R injury.
肠缺血再灌注（I/R）损伤是胃肠道手术患者常见的病理过程，导致局部肠道损伤和微血管通透性增加，最终导致肠道外多器官功能障碍或脓毒症。NLRP3 介导的炎症反应与 I/R 损伤有关。甲烷生理盐水（MS）具有抗焦亡作用。本研究旨在探讨 MS 对肠 I/R 损伤的保护作用及其潜在机制。在 MS 预处理后，通过使用非侵入性血管夹暂时夹闭小鼠肠系膜上动脉建立体内模型，并在 Caco-2 细胞上进行 OGD/R 建立体外模型。HE 和 TUNEL 染色结果显示 I/R 损伤后肠屏障损伤，与紧密连接蛋白的 IHC 染色结果一致。此外，NLRP3 信号通路的表达在 I/R 损伤后增加，抑制 NLRP3 激活可减少 Caco-2 细胞损伤，表明 NLRP3 介导的焦亡是 I/R 损伤后细胞死亡的主要形式之一。随后，我们发现 MS 通过抑制 NLRP3 介导的焦亡来改善 I/R 损伤后的肠屏障功能。MS 处理还减少了线粒体相关膜（MAM）的形成，这被认为是 NLRP3 炎症小体激活的平台。重要的是，MS 减轻了内质网应激，这与 PERK 信号通路有关。敲低 PERK，一种参与内质网应激和 MAM 形成的关键蛋白，逆转了 MS 的保护作用，表明 MS 通过减少内质网应激和 MAM 形成来抑制 NLRP3。总之，我们认为 MS 通过调节 PERK 信号通路来抑制 MAMs 和 NLRP3 炎症小体的激活，从而改善肠 I/R 损伤。
