Activating Parkin-dependent mitophagy alleviates oxidative stress, apoptosis, and promotes random-pattern skin flaps survival. Activating Parkin-dependent mitophagy alleviates oxidative stress, apoptosis, and promotes random-pattern skin flaps survival

The random-pattern skin flap is a crucial technique in reconstructive surgery and flap necrosis caused by ischemia/reperfusion injury is a major postoperative complication. Herein, we investigated the mechanism of mitophagy induced by Melatonin (ML) and its effect on the survival of skin flaps. Our results demonstrated that ML could activate mitophagy, ameliorate oxidative stress and alleviate apoptosis in TBHP-stimulated human umbilical vein endothelial cells in vitro. Inhibiting ML-induced mitophagy considerably abolished its protective effects. Moreover, knockdown of Parkin by siRNA inhibited ML-induced mitophagy, and subsequently exacerbated oxidative stress and apoptosis. Further study demonstrated that inhibition of AMPK reversed these protective effects of ML and downregulated the expression of TFEB. In the vivo study, ML effectively promoted flap survival by activating mitophagy and subsequently ameliorating oxidative stress and mitigating apoptosis. These results established that ML is a potent agent capable for increasing random-pattern skin flap survival by activating Parkin-dependent mitophagy through the AMPK-TFEB signaling pathway. Overall design: Comparative gene expression profiling analysis of RNA-seq data for HUVEC cells.

随机皮瓣（random-pattern skin flap）是重建外科中的关键技术，而缺血/再灌注损伤引发的皮瓣坏死是术后主要并发症。本研究探讨了褪黑素（Melatonin，ML）诱导的线粒体自噬（mitophagy）机制及其对皮瓣存活的影响。体外实验结果显示，褪黑素可激活线粒体自噬，缓解叔丁基过氧化氢（TBHP）刺激下人脐静脉内皮细胞（human umbilical vein endothelial cells, HUVEC）中的氧化应激并减轻细胞凋亡。抑制褪黑素诱导的线粒体自噬可显著抵消其保护作用。此外，通过小干扰RNA（siRNA）敲低帕金蛋白（Parkin）的表达，可抑制褪黑素诱导的线粒体自噬，进而加剧氧化应激与细胞凋亡。进一步研究显示，抑制腺苷酸活化蛋白激酶（AMPK）可逆转褪黑素的上述保护作用，并下调转录因子EB（TFEB）的表达。体内实验中，褪黑素通过激活线粒体自噬有效促进皮瓣存活，同时缓解氧化应激并减轻细胞凋亡。本研究结果证实，褪黑素是一种有效的调节剂，可通过AMPK-TFEB信号通路激活帕金蛋白依赖的线粒体自噬，从而提升随机皮瓣的存活率。实验整体设计：针对人脐静脉内皮细胞的RNA测序（RNA-seq）数据开展比较基因表达谱分析。