Abstract

Alveolar bone injury represents a prevalent clinical challenge in dentistry, for which stem cell-based therapy has emerged as a promising strategy to promote bone regeneration. N-acetylcysteine (NAC), a potent antioxidant, has been shown to modulate the PI3K-AKT signalling pathway and potentially enhance osteogenesis; however, the specific downstream effectors mediating this process remain unidentified. In this study, post-extraction serum metabolomic profiling revealed that alveolar bone injury is accompanied by systemic oxidative stress and metabolic remodelling. Transcriptomic analysis of antioxidant-treated dental stem cells further identified type VI collagen A1 (COL6A1) as a key functional mediator. We subsequently investigated the role of COL6A1 in antioxidant-mediated osteogenesis through immunofluorescence and protein assays, and performed knockdown and in vivo experiments to evaluate its function in oxidative stress regulation and osteogenic differentiation. Our results demonstrated that alveolar bone injury is associated with systemic oxidative stress and global metabolic alterations. In vitro, NAC markedly promoted the osteogenic differentiation of dental follicle stem cells (DFSCs) by activating the PI3K-AKT pathway and upregulating COL6A1. COL6A1 knockdown resulted in elevated reactive oxygen species (ROS) levels, impaired mitochondrial function, and attenuated NAC-mediated osteogenesis. In vivo, NAC-treated DFSCs exhibited enhanced bone healing and extracellular matrix (ECM) deposition in a rat model of alveolar bone injury, effects that were mediated through COL6A1 upregulation. Collectively, these findings demonstrate that NAC enhances osteogenesis in DFSCs via the PI3K-AKT-COL6A1 axis, offering a promising antioxidant-based strategy for stem cell therapies in bone regeneration. Moreover, COL6A1 is essential for maintaining redox homeostasis and represents a potential therapeutic target for improving regenerative outcomes.