Enhanced osteogenic potential of chitosan scaffolds loaded with Lawsonia inermis, hydroxyapatite particles, and dental pulp stem cells in rats

INTRODUCTION: Maxillary/alveolar bone reconstruction is vital for cleft and pre-prosthetic patients. Autogenous bone (iliac crest) is the gold standard for clefts due to its bone-forming ability. For large defects (trauma/tumor), the vascularized fibula flap is preferred for its strength and blood supply. METHODS: This study investigates the physicochemical and biological properties of chitosan (Cs)-based scaffolds. Three scaffold formulations were prepared for in vitro characterization: pure Cs, Cs enriched with 8% Lawsonia inermis extract (Cs-LI), and Cs combined with LI and nanohydroxyapatite (Cs-LI-HAPs). For the in vivo study, five experimental groups were evaluated in a rat mandibular defect model: sham (empty defect), control (Cs scaffold alone), Cs-LI, Cs-LI-HAPs, and Cs-LI-HAPs seeded with 1 × 10⁶ dental pulp stem cells (DPSCs). RESULTS: The synthesized HAPs showed a biomimetic apatite structure confirmed by FTIR and XRD, with a particle size of 730.2 ± 38.45 nm. Scaffold characterization demonstrated that Cs-LI-HAP had superior structural integrity, featuring interconnected porosity, improved mechanical strength (17.57 ± 1.49 MPa compressive strength), and a lower degradation rate (65.48 ± 10.35% at 4 weeks) compared to Cs and Cs-LI scaffolds. In vitro tests showed that Cs-LI-HAPs had good hemocompatibility and supported DPSC growth. In vivo, CBCT and histopathological analyses revealed that the Cs-LI-HAPs-DPSCs group exhibited significantly less fibrous tissue formation and greater bone regeneration compared to other groups. CONCLUSIONS: The Cs-LI-HAPs scaffold showed strong bone regeneration potential, with HAPs improving strength and stability, LI enhancing cell support, and DPSCs promoting new bone formation, making it a promising platform for maxillofacial defect repair.