Jinglei Tan, Caiqiang Chen
Berberine (BBR) is a natural isoquinoline alkaloid with antibacterial, anti-inflammatory and pro-angiogenic properties. This study aimed to investigate the therapeutic efficacy and underlying mechanism of a conditioned medium (CM) derived from berberine-preconditioned bone marrow-derived mesenchymal stem cells (BMSCs-BBR). BMSCs were isolated and phenotypically characterised by flow cytometry. A burn wound model was established in Wistar rats, and the model rats were randomly allocated to four groups treated with placebo gel, standard BMSCs-CM gel, BMSCs-BBR CM gel, or silver sulfadiazine cream. Wound healing rates were monitored macroscopically. On Day 21, skin tissues were harvested for histological analysis (H&E and Masson's trichrome staining), followed by immunofluorescence staining (CD31) and Western blot analysis (Collagen I, Collagen III and key proteins in the PI3K/AKT/eNOS signalling pathway). Among all treatments, BMSCs-BBR CM accelerated wound closure the most significantly, accompanied by improved epidermal regeneration, enhanced collagen deposition and organisation and a marked increase in capillary density. Furthermore, wounds treated with BMSCs-BBR CM exhibited notably upregulated Collagen I and Collagen III, and activation of the PI3K/AKT/eNOS pathway, as evidenced by increased phosphorylation of PI3K and AKT and elevated eNOS protein levels. Our findings demonstrate that the topical application of BMSCs-BBR CM gel potently promotes burn wound healing by improving the quality of tissue regeneration and stimulating angiogenesis via the activation of the PI3K/AKT/eNOS signalling pathway. This preconditioning strategy represents a promising acellular therapeutic approach for burn wound management.