Picroside II-mediated mitophagy activation inhibits ischemia-reperfusion-induced pyroptosis and apoptosis to promote ischemic flap survival.

BACKGROUND: Picroside II (P II), a glycoside derivative, exhibits anti-apoptotic and anti-inflammatory activities. However, its role in ischemic flap necrosis has not been fully clarified. PURPOSE: This study investigated the therapeutic potential of P II on ischemic flap necrosis and elucidated the underlying mechanisms, focusing on mitophagy regulation. STUDY DESIGN: An OGD/R model in HUVECs and a McFarlane flap model in rats were established. METHODS: The pharmacological effects of P II were assessed both in vitro and in vivo. Network pharmacology combined with molecular docking was applied to screen candidate targets and signaling pathways of P II. Subsequently, the modulatory effects of P II on mitophagy, pyroptosis, and apoptosis were experimentally validated. RESULTS: Bioinformatics linked P II to the modulation of mitophagy, pyroptosis, and apoptosis. Molecular docking, molecular dynamics simulations, and CETSA supported a potential association of P II with AMPK and PINK1. In vitro, P II treatment was associated with increased mitophagy-related activity and reduced NLRP3-inflammasome and Bax/Bak/caspase-3 signaling, while reducing IL-1β, IL-18, and cytochrome c release. These protective effects were attenuated by AMPK inhibition or PINK1 silencing, supporting the involvement of AMPK/PINK1 mediated mitophagy in P II's mechanism of action. In vivo, P II improved flap survival partly through AMPK/PINK1-mediated mitophagy activation and concurrently inhibited pyroptosis and apoptosis, while alleviating inflammation and oxidative stress. CONCLUSION: P II promotes ischemic skin flap survival partly through AMPK/PINK1-mediated mitophagy activation and inhibition of ischemia-reperfusion-induced pyroptosis and apoptosis. Other P II-related targets and pathways, including NLRP3 and TNF-α, may also contribute synergistically to its protective effects.