Osthole promotes skin flap survival by inhibiting ferroptosis and alleviating pyroptosis

Cnidium monnieri (L.) Cusson, a member of the Apiaceae family, is documented in the Compendium of Materia Medica as a treatment for traumatic injury with blood stasis ('pusun yuxue'), rheumatic arthralgia ('fengshi bitong'), and tinea and sores ('xuan chuang'). Osthole (OST), a coumarin derivative extracted from its fruit, possesses antioxidant and anti-inflammatory properties. Although OST is widely used for treating skin damage, its effect on skin flap survival remains unclear.

This study aimed to investigate the effect of OST on promoting the survival of ischemic flaps and to elucidate its underlying mechanisms.

Network pharmacology was utilized to identify potential pathways and targets of OST in preventing ischemia/reperfusion injury (IRI). To simulate skin flap IRI, the McFarlane skin flap model in rats and the oxygen-glucose deprivation/reperfusion (OGD/R) model in HUVECs were established. Blood perfusion was assessed using laser Doppler imaging, and histopathological changes in Area II flap tissues were evaluated by H&E staining. Oxidative stress was measured via MDA content, SOD activity, and ROS levels. Additionally, immunofluorescence was performed to examine the expression of TNF-α, IL-6, IL-1β, and CD31. Western blotting was used to assess the expression of proteins associated with angiogenesis, pyroptosis, and ferroptosis.

Network pharmacology analysis suggested that OST enhances skin flap survival through pathways associated with oxidative stress and NLRP3-mediated pyroptosis. OST administration promotes angiogenesis, increased blood perfusion, and improved skin flap viability. During the ischemia-reperfusion phase, OST attenuated oxidative stress and inflammatory responses. Mechanistically, OST inhibited ferroptosis by activating the Nrf2/SLC7A11/GPX4 signaling pathway and alleviated pyroptosis by downregulating the TLR4/NF-κB/NLRP3 pathway. Notably, these protective effects were partially reversed by the Nrf2 inhibitor ML385. Furthermore, the use of the ferroptosis inhibitor ferrostatin-1 and the caspase-1 inhibitor VX-765 suggests a potential crosstalk between ferroptosis and pyroptosis.

OST mitigated IRI by inhibiting ferroptosis and alleviating pyroptosis, providing a new therapeutic direction for enhancing skin flap survival.