Alveolar socket preservation with human umbilical cord mesenchymal stem cell-seeded hydroxyapatite-chitosan scaffolds: An in vivo assessment of osteoprotegerin and receptor activator of nuclear factor-κB expression.

Tooth extraction is a common procedure often followed by alveolar bone resorption, which may compromise future implant placement, prosthetic rehabilitation, esthetics, and periodontal support. Hydroxyapatite-chitosan (HA-Chi) scaffolds combined with human umbilical cord mesenchymal stem cells (hUCMSCs) may enhance bone healing by modulating bone remodeling pathways. This study evaluated the effects of hUCMSC-seeded HA-Chi scaffolds on osteoprotegerin (OPG) and receptor activator of nuclear factor-κB (RANK) expression during alveolar socket healing. In this randomized controlled in vivo experiment, 45 male Wistar rats underwent mandibular incisor extraction and were allocated to three groups: untreated control (C), HA-Chi scaffold only (T1), and hUCMSC-seeded HA-Chi scaffold (T2). Each group included 15 animals, with five evaluated at 7, 14, and 28 days. OPG and RANK expression were assessed immunohistochemically and data were analyzed using one-way ANOVA followed by Tukey's post hoc test. OPG expression increased progressively over time in all groups, whereas RANK expression decreased. The hUCMSC-seeded HA-Chi scaffold group consistently showed the highest OPG and lowest RANK expression at all observation periods. Overall intergroup differences were significant for both markers (p < 0.001). For OPG, no significant difference was observed between T1 and T2 at day 7, whereas significant differences emerged at days 14 and 28. For RANK, the hUCMSC-seeded group showed significantly lower expression than the control group at all-time points and than the scaffold-only group at day 28. hUCMSC-seeded HA-Chi scaffolds promoted a favorable bone remodeling profile by upregulated OPG and downregulated RANK, indicating strong potential for alveolar socket preservation after tooth extraction.