Apelin has been reported to regulate mitochondrial function in myocardial ischemia-reperfusion injury and cerebral ischemia-reperfusion injury. However, the role of apelin-13 in lung ischemia-reperfusion injury (LIRI) remains unclear. This study established an experimental rat model to evaluate the underlying mechanisms of apelin-13 on LIRI. Twenty-four rats were randomly divided to sham operation group (group SM), ischemia/reperfusion group (group IR), and apelin-13 treatment group (group APL). The effects of apelin-13 on LIRI were determined histologically using H&E staining, while the wet/dry weight ratio was used to assess lung edema caused by LIRI. Inflammatory cytokines were also detected in Bronchoalveolar lavage (BAL) fluid by ELISA. The protein expression of UCP2 and the morphological changes of mitochondria were determined by western blotting and electromicroscopy, respectively. The results demonstrated the structural damage of lung tissues and lung edema in group IR. An increased level of inflammatory cytokines including IL-1β, IL-6 and TNF-α was observed in rats with LIRI using ELISA. After that, oxidative stress and morphological damage of mitochondria were also shown in group IR. Yet, the application of apelin-13 reversed all these deleterious effects in group APL. The protective effects of apelin-13 were indicated by decreased reactive oxygen species (ROS) and elevated UCP2 expression levels in rats. In conclusion, this study revealed that apelin-13 had protective effects against LIRI via attenuating lung edema, the production of inflammatory cytokines, oxidative stress and mitochondrial dysfunction.

据报道，Apelin 在心肌缺血再灌注损伤和脑缺血再灌注损伤中调节线粒体功能。然而，apelin-13 在肺缺血再灌注损伤 (LIRI) 中的作用仍不清楚。本研究建立了实验大鼠模型来评估apelin-13对LIRI的潜在机制。 24只大鼠随机分为假手术组（SM组）、缺血/再灌注组（IR组）和apelin-13治疗组（APL组）。使用 H&E 染色在组织学上确定 apelin-13 对 LIRI 的影响，同时使用湿/干重比来评估 LIRI 引起的肺水肿。通过 ELISA，还在支气管肺泡灌洗 (BAL) 液中检测到炎症细胞因子。分别通过蛋白质印迹和电镜检测UCP2蛋白表达和线粒体形态变化。结果显示IR组存在肺组织结构损伤和肺水肿。使用 ELISA 观察到 LIRI 大鼠的炎症细胞因子水平升高，包括 IL-1β、IL-6 和 TNF-α。此后，IR组也出现氧化应激和线粒体形态损伤。然而，apelin-13 的应用逆转了 APL 组的所有这些有害影响。 apelin-13 的保护作用通过大鼠体内活性氧 (ROS) 的降低和 UCP2 表达水平的升高来体现。总之，这项研究表明 apelin-13 通过减轻肺水肿、炎性细胞因子的产生、氧化应激和线粒体功能障碍，对 LIRI 具有保护作用。