Effectiveness of rhBMP‐2 association to autogenous, allogeneic, and heterologous bone grafts

Abstract

Proteins with osteoinductive potential, especially recombinant human bone morphogenetic protein (rhBMP)‐2, have large effects on cell growth and their differentiation. The aim of this study was to assess repair of bone defects in rat calvaria with different types of grafts associated with rhBMP‐2, through immunohistochemistry and micro computed tomography (CT) analyses. A total of 35 male Wistar rats were selected, each weighing ~250 g, with a waiting period of 6 weeks from the creation of the defect to the sacrifice, and divided into five groups (n = 7): autograft plus 5 μg rhBMP‐2 (AuG/BMP‐2); allograft plus 5 μg rhBMP‐2 (AlG/BMP‐2); xenograft (heterologous) plus 5 μg rhBMP‐2 (XeG/BMP‐2); 5 μg rhBMP‐2 (BMP‐2) and the control group (n = 7). The micro CT reveal that all groups associating different bone grafts with BMP‐2 showed increased bone formation compared to the control. The immunostaining show that osteocalcin and bone sialoprotein were higher in groups with BMP‐2 than control group; BMP was high expressed in AuG/BMP‐2, AlG/BMP‐2, and BMP‐2; vascular endothelial growth factor (VEGF) was more expressed in groups with BMP‐2; VEGF‐R2 was low to moderate in AuG/BMP‐2, XeG/BMP‐2, and BMP‐2, predominantly moderate in AlG/BMP‐2 and low in the control; CD‐31 was predominantly moderate in AuG/BMP‐2, AlG/BMP‐2, and XeG/BMP‐2, low to moderate in BMP‐2 and low in the control. The results revealed that rhBMP‐2 improved bone repair when administered alone, or when associated with different bone grafts.

Evaluation of the effects of bone morphogenetic protein-2 on the healing of bone calvarial defects in ovariectomized rats

“…In the present study, as in previous studies, the size of the critical-size defect was selected as 4 mm [7,29]. Although it is difficult to compare human biology and animal biology, rats are frequently used to ensure the reproducibility of experiments and for studies that seek to attain a 'proof of principle' [18,42]. The rat calvarial site defect model is an excellent model for bone regeneration in the craniofacial region.…”

“…The rat calvarial site defect model is an excellent model for bone regeneration in the craniofacial region. As the calvarial site is stable, defects in this site are useful for the examination of histological and immunohistochemical parameters [18]. In the present study, the experiment period was determined as 8 weeks.…”

“…The results of studies by Tera et al [52] and Ishigaki et al [54] were similar to those of our study. In the literature, many immunohistochemical and histological studies have shown that rhBMP-2 is effective in increasing new bone formation [18,31,40,[55][56][57]. Cheng et al showed that BMP-2 did not produce a statistically significant difference in bone volume in an experimental study in rats.…”

“…In immunohistochemical studies, the type of biomarkers used is important for analyzing, imaging, and examining regeneration in the bone defect area [16]. For instance, osteocalcin (OC) is a strong marker of newly formed bone [17,18]. Osteonectin (ON) is a biological modulator and a known proliferative agent [19].…”

Soluble Expression and Purification of Bioactive Recombinant Human Bone Morphogenetic Protein-2 from Escherichia coli

“…The stabilization of disulfide bonds involves the protein interaction with transmembrane serine/threonine kinase receptors on osteogenic cells, leading to activate cell proliferation and differentiation of osteoblasts (Reddi, 2000). Owing to its osteoinductive capacity, BMP-2 renders a therapeutic protein for de novo bone formation in clinical use, which is utilized as an alternative to bone autografting during the healing of critical fractures, for spinal fusions or the treatment of bone and periodontal defects including dental implants (Gautschi et al, 2007;McKay et al, 2007;Bessa et al, 2008;Tang et al, 2009;Kimura et al, 2010;Shimono et al, 2010;Luo et al, 2012;Marques et al, 2015;Gomes-Ferreira et al, 2016;Poon et al, 2016;Herford, 2017;Gonzaga et al, 2019).…”