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.

Abstract

To investigate the effect of poly (lactide-co-glycolide) (PLGA)-coated β-tricalcium phosphate (TCP) as a scaffold on bone regeneration in rat calvaria. 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. At 4weeks, 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 6weeks, 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. The application of PLGA-coated β-TCP could promote bone regeneration to similar extent as the β-TCP biomaterial in this invivo model.