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

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.

Bone repair of critical-sized defects in Wistar rats treated with autogenic, allogenic or xenogenic bone grafts alone or in combination with natural latex fraction F1.

Bone grafts are used in the medical-surgical field for anatomical and functional reconstruction of lost bone areas, aiding the bone repair process by osteogenesis, osteinduction and osteoconduction. New materials such as F1 (fraction 1) protein extracted from the rubber tree Hevea brasiliensis have been investigated and currently present important properties for tissue repair, and are associated with neoangiogenesis, promoting cell adhesion and extracellular matrix formation. The main objective of this study was to investigate the association of F1 protein to different bone grafts in the repair of critical bone defects in the calvaria of Wistar rats. A total of 112 Wistar rats were divided as follows: autograft (AuG), allograft (AlG), xenograft (XeG), autograft/F1 (AuG-F1), allograft/F1 (AlG-F1), xenograft/F1 (XeG-F1), F1 (F1), control (CTL), with a waiting period of 4 and 6 weeks (w). The stereological AuG, AlG, AuG-F1 and AlG-F1 results had greater bone neoformation (p < 0.05). For immunohistochemistry, the angiogenic and osteogenic factors were higher for AuG-F1 and AlG-F1. TRAP-positive cells were higher in XeG-F1 and AlG (37 ± 9.53, 13.3 ± 4.16) (4 w) and XeG, AlG-F1 and XeG-F1 (20.33 ± 7.37; 15.25 ± 6.02, 19.33 ± 3.21) (6 w). For zymography, F1 showed increased gelatinolytic activity of MMP-2 and -9. It was concluded that the bone graft associated or not with F1 increases the angiogenic and osteogenic, biochemical and stereological factors.

The effect of simvastatin treatment on bone repair of femoral fracture in animal model.

The aim of this research was to evaluate the fracture healing area in osteoporotic femur of female rats restrained by stainless steel wire by statin administration in two different doses (5 mg and 20 mg). Ninety female rats were divided into six groups (n = 15): SH, SH-5 mg, SH-20 mg, OVX, OVX-5 mg, and OVX-20 mg. The surgery consisted of the fracture of the left femur bone and stabilization by K-wire and the administration was restricted and weekly controlled in the drinking water. The euthanasia was conducted at three different moments, five animals per period: 7 d, 14 d, and 28 d. Densitometry, zymography, and histological analyses showed a significant difference between some groups. According to these findings, simvastatin promoted a positive action for bone repair, especially in the osteometabolic group treated with 20 mg of the drug.