Platelet-rich fibrin/biphasic calcium phosphate impairs osteoclast differentiation and promotes apoptosis by the intrinsic mitochondrial pathway in chronic periodontitis.

Abstract

The study explored the effect of platelet-rich fibrin/biphasic calcium phosphate (PRF/BCP) on differentiation and survival of osteoclasts obtained from peripheral blood of CP patients. Peripheral blood mononuclear cells (PBMCs) from 25 patients with chronic periodontitis (CP) and 25 healthy individuals were assayed for cluster of differentiation14+ (CD14+ ) expression and monocytes were induced to differentiate into osteoclasts for 21 days in-vitro in the presence of macrophage colony stimulating factor (M-CSF) and receptor activator of nuclear factor-kappa B ligand (RANKL). We assessed the number of osteoclasts by tartrate-acid resistant acid phosphatase (TRAP)-positivity. The mechanism of apoptosis was studied with reference to expression of Bcl-2, Bax, Bcl-xL, nuclear factor kappa-light chain enhancer of activated B cells (NF-κB), caspase 3/9 and DNA fragmentation. We observed a relative increase in the proportion of circulating osteoclasts in test group than control group (healthy individuals). In addition, osteoclast precursors in untreated cells (CP) were more osteoclastogenic as compared to cells treated with PRF/BCP and hence, there was a significant increase in the number of osteoclasts in CP. In PRF/BCP treated cells, we found a direct inhibition of transcription factor NF-κB with an increased caspase 3/9 levels and caspase 3 activity. Additionally, the protein expression and transcriptional profile of Bax was upregulated and Bcl-2 and Bcl-xL levels were down-regulated on treatment with PRF/BCP. Our results revealed that the PRF/BCP displayed an inhibitory role in osteoclasts formation and its molecular mechanism of action was related to the apoptosis induction through intrinsic mitochondrial pathway.