Fatima Ali, Nadia Wajid, Muhammad Shahid Nadeem
Burn injuries are associated with excessive oxidative stress and inflammation that impair mesenchymal stem cell (MSC) survival and regenerative function. This study investigated whether N-acetylcysteine (NAC) preconditioning could enhance the therapeutic efficacy of bone marrow-derived MSCs (BMSCs) in oxidative stress conditions and burn wound healing. In vitro, BMSCs were preconditioned with NAC (5 or 10 mM) prior to H₂O₂ exposure, and cell viability, proliferation, oxidative stress markers, and regenerative gene and protein expression were evaluated. In vivo, BMSCs isolated from male Sprague Dawley rats were transplanted into second-degree thermal burn wounds induced in female rats, and wound healing was assessed over 21 days using macroscopic, histological, biochemical, and molecular analyses. NAC preconditioning significantly improved BMSC viability, proliferation, and morphology under oxidative stress while reducing LDH release. NAC-treated BMSCs exhibited increased antioxidant enzyme activities (SOD, CAT, and GSH), reduced malondialdehyde (MDA) levels, and enhanced expression of PCNA, SDF-1, CXCR4, VEGF-A, and IGF-1. In vivo, transplantation of NAC-preconditioned BMSCs accelerated wound contraction, improved re-epithelialization, increased hydroxyproline content, and promoted collagen deposition and tissue regeneration. Furthermore, NAC-preconditioned BMSCs enhanced antioxidant defenses and upregulated SDF-1, CXCR4, VEGF-A, and IGF-1 expression in wound tissues. Collectively, these findings demonstrate that NAC preconditioning enhances the survival, antioxidant capacity, paracrine activity, and regenerative potential of BMSCs, resulting in improved burn wound healing. NAC-preconditioned BMSCs may represent a promising strategy for stem cell-based treatment of burn injuries.