Osthole promotes skin flap survival by inhibiting ferroptosis and alleviating pyroptosis

Ethnopharmacological relevance: 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.

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

Materials and methods: 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.

Results: 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.

Conclusion: OST mitigated IRI by inhibiting Ferroptosis and alleviating Pyroptosis, providing a new therapeutic direction for enhancing skin FLAP survival.

Ferroptosis; Nrf2; Osthole; Pyroptosis; Skin flap.