Effect of poly (lactide‐co‐glycolide) (PLGA)‐coated beta‐tricalcium phosphate on the healing of rat calvarial bone defects: a comparative study with pure‐phase beta‐tricalcium phosphate

OBJECTIVES: To investigate the effect of poly (lactide-co-glycolide) (PLGA)-coated β-tricalcium phosphate (TCP) as a scaffold on bone regeneration in rat calvaria. MATERIAL AND METHODS: Bilateral critical-sized defects were created in the calvaria of 20 Sprague Dawley rats. Defects of each rat were filled with pure-phase β-TCP or PLGA/β-TCP, or left as unfilled control. The healing was evaluated by micro-computed tomography, histological, and immunohistochemical analyses. Tartrate-resistant acid phosphatase (TRAP) staining was also performed to assess the resorption activity. RESULTS: At 4 weeks, ingrowth of cells from the surrounding tissue into the β-TCP and PLGA/β-TCP biomaterials were observed in the defect area, and new bone formation had started. At 6 weeks, the value for defect closure in the β-TCP group was significantly greater than that in the unfilled control (P < 0.01). A significantly greater level of new bone formation was found in the β-TCP group (P < 0.01) and PLGA/β-TCP group (P < 0.05) than that in the control group, while no significant difference was found between the β-TCP and PLGA/β-TCP groups. At both time points, the height of new tissue/biomaterial in the central third of the defect was significantly increased when the β-TCP or PLGA/β-TCP was used. Proliferating cell nuclear antigen -positive cells were observed around and inside the β-TCP or PLGA/β-TCP, and TRAP-positive cells were found at the surface of the biomaterials, suggesting that remodeling was occurring. CONCLUSION: The application of PLGA-coated β-TCP could promote bone regeneration to similar extent as the β-TCP biomaterial in this in vivo model.