Antimicrobial photodynamic therapy with Ligularia fischeri extract and red light improves the restoration of Staphylococcus aureus-infected wounds in BALB/c mice

Antimicrobial photodynamic therapy is a promising approach for mitigating antimicrobial infections due to its effective skin homeostasis recovery and lower risk of inducing bacterial resistance. This study aims to investigate the ameliorative effects of combined treatment of red light and Ligularia fischeri extract on Staphylococcus aureus -infected wounds in BALB/c mice. The effects of L. fischeri extract (LF), red light (RL), and their combined treatment, referred to as LF-mediated antimicrobial photodynamic therapy (LF+RL), against S. aureus and S. aureus -infected wounds in BALB/c mice were determined. LF+RL demonstrated antimicrobial efficacy by reducing the number of S. aureus Korean Collection for Type Cultures (KCTC) 3,881 from 8.47 to 3.68 Log CFU/mL. It inhibited S. aureus growth in wounds, expedited wound size reduction, facilitated reepithelialization of the epidermis, and enhanced fibroplasia and collagen deposition in the dermis, mitigating S. aureus -induced impairment. LF+RL also up-regulated the expression of transforming growth factor-β, fibroblast growth factor-2 (FGF-2), FGF-7, and FGF-10 mRNA. These findings suggest that LF+RL improves wound healing following S. aureus infection. L. fischeri extract emerges as a potent photosensitizer responding to RL, exhibiting an anti-staphylococcal effect. LF+RL holds promise for the development of a novel therapeutic method to attenuate microbial infections.