RESUMO
We have recently identified plasma-irradiated silk fibroin (P-AF) as a key regulator of bone matrix properties and composition. Bone matrix properties were tested in 48 femur critical size defects (3.25 mm in diameter) with the expression of osteoblast specific genes at 1 and 2 weeks after surgery. The scaffolds were characterized by various states of techniques; the scanning electronic microcopy revealed the large sized pores in the aqueous-based silk fibroin (A-F) scaffold and showed no alteration into the architecture by the addition of plasma irradiation. The contact angle measurements confirmed the introduction of plasma helped to change the hydrophobic nature into hydrophilic. The histological analyses confirmed the presence of silk fibroin in scaffolds and newly formed bone around the scaffolds. Immunohistochemical examination revealed the increased expression pattern in a set of osteoblast specific genes (TGF-ß, TGF-ß type III receptor, Runx2, type I collagen and osteocalcin). These data were the first to show that the properties of bone matrix are regulated, specifically through Runx2 pathway in P-AF group. Thus, an employment of P-AF increases several compositional properties of bone, including increased bone matrix, mineral concentration, cortical thickness, and trabecular bone volume.
Assuntos
Regeneração Óssea/fisiologia , Fibroínas/química , Osteoblastos/citologia , Alicerces Teciduais , Animais , Biomarcadores/metabolismo , Densidade Óssea , Colágeno Tipo I/genética , Colágeno Tipo I/metabolismo , Subunidade alfa 1 de Fator de Ligação ao Core/genética , Subunidade alfa 1 de Fator de Ligação ao Core/metabolismo , Fêmur/lesões , Fêmur/fisiopatologia , Expressão Gênica , Interações Hidrofóbicas e Hidrofílicas , Masculino , Osteoblastos/fisiologia , Osteocalcina/genética , Osteocalcina/metabolismo , Gases em Plasma , Proteoglicanas/genética , Proteoglicanas/metabolismo , Coelhos , Receptores de Fatores de Crescimento Transformadores beta/genética , Receptores de Fatores de Crescimento Transformadores beta/metabolismo , Transdução de Sinais , Fator de Crescimento Transformador beta/genética , Fator de Crescimento Transformador beta/metabolismoRESUMO
The influence of calcium phosphate (Ca-P) coating and surface roughness on the trabecular bone response of titanium implants was investigated. Four types of titanium implants, i.e. blasted with titanium powder, sintered with titanium beads, titanium powder blasted and provided with an additional Ca-P coating, and titanium beads with Ca-P coating, were prepared. The Ca-P coating was deposited by ion beam dynamic mixing method. The Ca-P coating was rapid heat-treated with infrared radiation at 700 degrees C. The implants were inserted into the trabecular bone of the left and right femoral condyles of 16 rabbits. After implantation periods of 2, 3, 4 and 12 weeks, the bone-implant interface was evaluated histologically and histomorphometrically. Histological evaluation revealed new bone formation around different implant materials after already 3 weeks of implantation. After 12 weeks, mature trabecular bone surrounded all implants. At 3 and 4 weeks of implantation, no difference existed in bone contact to the various implant materials. On the other hand, after 12 weeks of implantation the highest percentage of bone contact was found around the Ca-P coated beads implants. Supported by the results, we concluded that the combination of surface geometry and Ca-P coating benefits the implant-bone response during the healing phase.