Schisandrin B enhances autophagy and random flaps survival through the PPARG-mediated PI3K/AKT/mTOR signaling pathway

Necrosis of random flaps significantly hinders their clinical implementation and remains a major challenge for surgeons. Schisandrin B (Sch B), a lignan compound extracted from the traditional Chinese herb Schisandra chinensis, has potential application prospects in the treatment and prevention of various diseases. This study aimed to examine the effects of Sch B in a rat model of random flaps and investigate the underlying mechanisms that may explain these effects. By performing network pharmacology analysis, we identified critical targets and signaling pathways involved in the effects of Sch B on flap viability. In vitro, treatment with Sch B significantly promoted the proliferation, migration, and capillary formation of human umbilical vein endothelial cells (HUVECs) induced by hydrogen peroxide (H₂O₂). In vivo, Sch B-treated flaps exhibited markedly larger viable areas, as validated using hematoxylin and eosin (H&E) staining as well as laser Doppler blood flow (LDBF) imaging. Immunohistochemical (IHC) and Western blot analyses provided evidence that Sch B significantly reduced oxidative stress and inflammation while enhancing angiogenesis. The autophagy inhibitor 3-methyladenine (3 MA) modulated Sch B's effects, underscoring the essential role of autophagy in its efficacy. Additionally, molecular docking studies and further validation using the selective small-molecule inhibitor T0070907 targeting Peroxisome Proliferator-Activated Receptor Gamma (PPARG) indicated that Sch B activates PPARG, which inhibits the PI3K-AKT-mTOR pathway. In conclusion, our results suggest that Sch B promotes autophagy via the PPARG-mediated PI3K-AKT-mTOR pathway to enhance flap survival, providing a theoretical reference point for novel strategies in skin wound repair.