Exosomes Released by Periodontal Ligament Stem Cells in Low-Inflammatory Microenvironment Promote Bone Tissue Regeneration

Background:This study investigates the effects of periodontal ligament stem cells preconditioned with low-inflammatory stimuli and their derived exosomes on jaw bone regeneration.Methods:Periodontal ligament stem cells (PDLSCs) were treated with varying concentrations of inflammatory induction medium to establish low-inflammatory PDLSCs, from which exosomes were subsequently extracted. The osteogenic effects of the exosomes derived from i-PDLSCs (i-PDLSCs-exo) on osteoblasts were evaluated in vitro.Results:The findings demonstrated that PDLSCs subjected to low-inflammatory conditions (i-PDLSCs) exhibited a significantly increased expression of osteogenesis-related genes, such as alkaline phosphatase (ALP) and Osteocalcin (OCN), and showed enhanced mineralized nodule formation. Additionally, there was an increase in the secretion of i-PDLSCs-exo, and at an optimal concentration of 20 μg/mL, they were taken up by hFOB1.19 cells, enhancing mineralized nodule formation and osteogenic gene expression. In vivo, a chondroitin sulfate hydrogel loaded with i-PDLSCs-exo was implanted into periodontal bone defects in Sprague–Dawley rats. This treatment group demonstrated superior bone regeneration compared to both the chondroitin sulfate hydrogel alone and the blank control groups.Conclusion:Collectively, these findings suggest that short-term pretreatment with low concentrations of inflammatory factors enhances the osteogenic potential of PDLSCs and their exosomes, promoting the regeneration of jaw bone defects in rats. This approach offers a promising therapeutic strategy for repairing bone tissue defects.