Uso isolado da fibrina rica em plaquetas (PRF) na forma de membrana e da PRF injetável associada ao osso bovino particulado em defeitos não críticos na tíbia de ratos: formação óssea e expressão de biomarcadores

Abstract

Platelet-rich fibrin (PRF) has been widely proposed in regenerative procedures. In particular, low centrifugation force protocols have been highlighted by confer a higher concentration of osteoprogenitor cells and growth factors to the leukoplatelet concentrate. Injectable PRF (i- PRF) as well as PRF in form of membrane obtained through the Fibrin Protocol are part of this group. Furthermore, recent studies have investigated the regenerative potential of a material formed by the association between deproteinized bovine bone mineral (DBBM) and i-PRF, known as “sticky bone”. However, the effectiveness of this material has not yet been evaluated, through preclinical and clinical studies, in alveolar ridge preservation (ARP) models. The aim of this study was to investigate the efficacy of platelet-rich fibrin membrane (PRF) alone and i-PRF mixed with deproteinized bovine bone mineral (DBBM) in the treatment of non-critical tibial defects in rats. Non-critical bone defects in tibias (3.5mm x 1.5mm) of sixty-four rats were made and filled with different materials according to each experimental group: CO: bone defects filled with blood clot; PRF: PRF membranes obtained by fibrin protocol; BO: DBBM alone and SB: i-PRF mixed with DBBM. Computed microtomography (CT), histological/histomorphometric analysis and expression of molecular markers were performed after 15 and 45 days. In the defect cortical area PRF showed similar results to the other investigated groups for the thickness and bone formation analysis by CT in all analyzed periods. The same analysis demonstrated the superiority of the BO and SB groups for bone formation in relation to the control group after 45 days (p<0.05). The addition of OBD (BO and SB groups) promoted greater bone formation, a greater number of trabeculae, in addition to a smaller space between the trabeculae compared to the PRF and CO groups in both analyzed periods (p<0.05), considering the cortical and medullary area in the microtomographic analysis. Histomorphometry analysis showed a similar percentage of newly formed bone between all experimental groups at 15 and 45 days (p>0.05). i-PRF associated with OBD did not increase bone formation compared to OBD alone in both histomorphometry and CT analyses for all analyzed periods. The SB group showed a lower percentage of residual biomaterial particles compared to the BO group in the histomorphometry analysis for the 45-day period (p<0.05). The expression of bone molecular markers showed higher expression of Alpl, Bglap and Runx2 genes for the BO group compared to the other investigated groups (p<0.05). In conclusion, the isolated use of OBD resulted in greater bone formation and expression of molecular markers compared to the PRF and CO groups in non-critical bone defects. Furthermore, the addition of i-PRF to OBD did not increase its bone formation potential in the performed analyses.