Objective <p>This study aims to investigate the therapeutic effect of exogenous mitochondrial transplantation (MT) on lung ischemia-reperfusion injury (LI/RI), and analyze the impact of MT on alveolar epithelial cell function and the ultrastructure of the alveolar epithelial barrier.</p> Methods <p>To simulate the pathological process of LI/RI, we established a hypoxia-reoxygenation model using mouse alveolar epithelial cells (MLE-12 cells) and a LI/RI model in male C57BL/6 mice. Based on these models, we further evaluated the therapeutic effect of mouse liver-derived mitochondrial transplantation on LI/RI.</p> Results <p>The results of this study showed that MT exhibits significant therapeutic potential in LI/RI. Both in vitro and in vivo experiments confirmed that MT can significantly ameliorate lung tissue injury by reducing oxidative stress levels, alleviating inflammatory responses, and decreasing cell apoptosis and necrosis. Meanwhile, MT is capable of alleviating alveolar epithelial cell dysfunction, reducing the disruption of tight junction proteins, and preserving the integrity of the alveolar epithelial barrier, thereby mitigating LI/RI.</p> Conclusion <p>Our study confirmed in the LI/RI model that MT therapy can repair the alveolar barrier structural damage caused by ischemia-reperfusion by targeting the regulation of the expression levels of tight junction proteins in alveolar epithelial cells. This finding provides a new perspective for clarifying the target of action through which MT therapy protects alveolar barrier function.</p>