β-Tricalcium phosphate promotes cell proliferation, osteogenesis and bone regeneration in intrabony defects in dogs

Objective: This study investigates the effect of the new synthetic bone grafting material, high pure-phase beta-tricalcium phosphate (Cerasorb (R) M, granule size 500-1000 mu m), on the osteogenesis process and proliferation marker in bone mar-row stromal cells (BMSCs) and its regenerative effect in the periodontal intrabony defects in dogs. Design: The effect of Cerasorb (R) M (20 and 40 mg ml(-1) for 1 and 2 weeks) on the proliferation rate of BMSCs was assessed by 3-(4,S-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay on the proliferating cell nuclear antigen (PCNA) by immunoblotting and on alkaline phosphatase level by colourimetric assay. The regenerative effect of Cerasorb (R) M in the periodontal intrabony defects in dogs was investigated by histological and immunohistochemical analysis after 3 and 6 months of grafting. Results: Incubation of BMSCs with Cerasorb (R) M for 2 weeks led to significant increase in cell proliferation rate, which was associated with increased PCNA. Cerasorb (R) M significantly increased the production of alkaline phosphatase as a marker for the osteogenic stromal lineage and for differentiation and bone formation in BMSCs after 2 weeks. In the histological features and immunohistochemical analysis of PCNA of the intrabony defects in dogs augmented with Cerasorb (R) M, osteoid tissue with a plate-like structure and cellular mesenchymal proliferation besides osteoid islands joined by bridges were observed after 3 months. Six months after the implantation, the Cerasorb (R) M granules were replaced by abundant new plate-like bone besides PCNA-enriched, small, oval-shaped mononuclear cells and multinucleated-giant cells that were attached to newly formed bones. No remains of the Cerasorb (R) M granules could be seen after 3 and 6 months with the newly formed plate-like bones and no histological sign of inflammatory reaction or formation of foreign-body granulomas. Conclusion: Cerasorb (R) M may induce cell proliferation vi a induction of PCNA that may induce early osteogenesis and bone formation. Cerasorb (R) M regenerated the bone completely in intrabony defects and that this regeneration was highly associated with PCNA expression in different cell lineage. (C) 2009 Elsevier Ltd. All rights reserved.