Phillyrin attenuates high glucose-induced ferroptosis in gingival cells through the activation of 5' adenosine monophosphate-activated protein kinase signaling.

BACKGROUND/PURPOSE: Delayed wound healing in diabetes involves multiple factors, with ferroptosis being one of the key mechanisms. Ferroptosis, marked by iron accumulation and lipid peroxidation, has been implicated in the pathogenesis of various diseases; however, its role in oral wound healing remains unclear. Here, we evaluated its involvement in impaired wound healing, as well as the therapeutic effects of phillyrin, a natural lignan with the potential to ameliorate oxidative stress and diabetic complications. MATERIALS AND METHODS: Smulow-Glickman (S-G) gingival epithelial cells were exposed to high-glucose conditions, followed by treatment with phillyrin. PrestBlue assay and 2 well culture-insert were utilized to assess cell viability and wound healing capacity, respectively. Lipid peroxidation and oxidative stress were determined using commercial assay kits to measure malondialdehyde (MDA) and 8-hydroxy-2-deoxyguanosine (8-OHdG), respectively. Intracellular Fe2+ was measured using FerroOrange fluorescent probe. RESULTS: High glucose, like the ferroptosis inducer erastin, reduced cell viability and wound-healing capacity, whereas ferroptosis inhibitor Ferrostatin-1 or phillyrin treatment conferred comparable protection. Also, we showed that the characteristics of ferroptosis were elevated in high glucose-treated cells, while phillyrin administration reduced these features in a dose-dependent manner. More importantly, we found that this effect may result from phillyrin restoring high-glucose-suppressed 5' adenosine monophosphate-activated protein kinase (AMPK) phosphorylation, thereby regulating anti-ferroptotic factors and enhancing cellular resilience against ferroptosis. CONCLUSION: These findings suggest that phillyrin may improve impaired oral wound healing in diabetes through the activation of AMPK and upregulation of anti-ferroptotic mechanisms, underscoring its promise in the treatment of complications associated with diabetes.