Adipose-Derived Mesenchymal Stem Cell Osteodifferentiation after Exposure to Beta-Tricalcium Phosphate Bioceramic Granules with 300 to 600 and 600 to 1,000 µm Sizes

Beta-tricalcium phosphate (β-TCP) is a synthetic graft material with excellent biocompatibility, osteoconductivity, and osteoinductivity. β-TCP may induce adipose-derived mesenchymal stem cells (ADMSCs) osteodifferentiation. This study aims to investigate the osteoinductivity of 300 to 600 and 600 to 1,000μm β-TCP in ADMSCs.ADMSCs were obtained from the visceral adipose tissue of young male rabbits. To determine the osteoinductive ability, bone morphogenic protein 2 (BMP-2), Osterix, runt-related transcription factor 2 (Runx2), alkaline phosphatase (ALP), osteopontin, and osteonectin expression was examined using an immunochemical assay on ADMSCs conditioned with an osteogenic medium and a β-TCP bioceramic with granule sizes of 300 to 600 and 600 to 1,000 µm (100 ng diluted to 100 nmol as the final concentration). A 3,3'-diaminobenzidine staining kit was used for immunocytochemical staining. Anti-BMP-2, anti-Osterix, anti-Runx2, anti-ALP, anti-osteopontin, and anti-osteonectin monoclonal antibodies were employed at a 1:500 dilution. A light microscope with magnifications of 400× and 1,000× was used to manually observe and examine cultures in five different fields of view.BMP 2, Runx2, Osterix, and ALP expression was higher in ADMSCs + β-TCP 300 to 600 µm compared with the control group (<i>p</i> < 0.05). Osteonectin and osteopontin expression was higher in ADMSCs + 300 to 600 µm β-TCP compared with the control group (<i>p</i> < 0.05) and ADMSCs + 600 to 1,000 µm β-TCP (<i>p</i> < 0.05).ADMSC osteodifferentiation was influenced by β-TCP bioceramic granule size. The considerable difference in osteonectin and osteopontin expression supports the idea that 300 to 600 µm β-TCP induce ADMSCs osteodifferentiation than 600 to 1,000 µm β-TCP.