Investigating the repair of alveolar bone defects by gelatin methacrylate hydrogels-encapsulated human periodontal ligament stem cells

Although various efforts have been made to develop effective treatments for alveolar bone defect, alveolar regeneration has been emerging as the one with the most potential Herein, we investigated the potential of gelatin methacrylate (GelMA) hydrogels-encapsulated human periodontal ligament stem cells (hPDLSCs) to regenerate alveolar bone. The easy, rapid, and cost-effective nature of GelMA hydrogels makes them a promising mode of stem cell-delivery for clinically relevant alveolar bone regeneration. More importantly, GelMA hydrogels provide an optimal niche for hPDLSCs proliferation, migration and osteogenic differentiation, which are critical for alveolar bone regeneration. In this study, we examined the microstructure of GelMA hydrogels, and identified a highly porous and interconnected network. Compressive test of GelMA hydrogels showed that the stress reached a maximum value of 13.67 ± 0.03 kPa when the strain reached 55%. The maximum values of swelling ratio were 700 ± 47% at the fifth hour. The proliferation rate of hPDLSCs in the GelMA hydrogels resembled that in 2D culture and gradually increased. We established a critical-sized rat model of alveolar bone defects, and applied Micro-CT to assess new bone formation. Compared to the control group, there was substantial bone regeneration in the GelMA + hPDLSCs group at both 4 and 8 weeks after the operation. Histological analysis results were consistent with Micro-CT results. Our study demonstrates that the GelMA hydrogels-encapsulated hPDLSCs have a significant alveolar regenerative potential, and may represent a new strategy for the therapy of alveolar bone defects.