Efficiency analysis of commercial polymeric membranes for bone regeneration in rat cranial defects

Purpose: To evaluate the in vivo efficiency of commercial polymeric membranes for guided bone regeneration. Methods: Rat calvarial critical size defects was treated with LuminaCoat (LC), Surgitime PTFE (SP), GenDerm (GD), Pratix (PR), Techgraft (TG) or control (C-) and histomorphometric analysis determined the percentage of new bone, connective tissue and biomaterial at 1 or 3 months. Statistical analysis used ANOVA with Tukey's post-test for means at same experimental time and the paired Student's t test between the two periods, considering p < 0.05. Results: New bone at 1 month was higher for SP, TG and C-, at 3 months there were no differences, and between 1 and 3 months PR had greater increase growthing. Connective tissue at 1 month was higher for C-, at 3 months for PR, TG and C-, and between 1 and 3 months C- had sharp decline. Biomaterial at 1 month was higher for LC, in 3 months for SP and TG, and between 1 and 3 months, LC, GD and TG had more decreasing mean. Conclusion: SP had greater osteopromotive capacity and limitation of connective ingrowth, but did not exhibit degradation. PR and TG had favorable osteopromotion, LC less connective tissue and GD more accelerated biodegradation.

A biocomplex to repair experimental critical size defects associated with photobiomodulation therapy

The association of scaffolds to repair extensive bone defects can contribute to their evolution and morphophysiological recomposition. The incorporation of particulate biomaterials into three-dimensional fibrin bioproducts together with photobiomodulation therapy (PBM) has potential and can improve regenerative medicine procedures. The objective of this experiment was to evaluate the effects of PBM therapy on critical size defects filled with xenogenic bone substitute associated with fibrin biopolymer. Methods: A critical defect of 8 mm was performed in 36 Wistar male adult rats that were divided into four groups. Groups BC and BC-PBM were defined as controls with defects filled by a clot (without or with PBM, respectively) and groups XS and XS-PBM that comprised those filled with biocomplex Bio-OssTM in association with fibrin biopolymer. PBM was applied immediately after the surgery and three times a week every other day, with the parameters: wavelength of 830 nm, energy density 6.2 J/cm2, output power 30 mW, beam area of 0.116 cm2, irradiance 0.258,62 W/cm2, energy/point 0.72 J, total energy 2.88 J. Fourteen and 42 days after the surgery, animals were euthanatized and subjected to microtomography, qualitative and quantitative histological analysis. Results: The BC-PBM and XS-PBM groups had a similar evolution in the tissue repair process, with a higher density of the volume of new formed bone in relation to the groups without PBM (p = 0.04086; p = 0.07093, respectively). Intense vascular proliferation and bone deposition around the biomaterial particles were observed in the animals of the groups in which biocomplex was applied (XS and XS-PBM). Conclusion: PBM therapy allowed an improvement in the formation of new bone, with a more organized deposition of collagen fibers in the defect area. Biocomplex favored the insertion and permanence of the particulate material in bone defects, creating a favorable microenvironment for accelerate repair process.(AU)

A biocomplex to repair experimental critical size defects associated with photobiomodulation therapy

Abstract Background: The association of scaffolds to repair extensive bone defects can contribute to their evolution and morphophysiological recomposition. The incorporation of particulate biomaterials into three-dimensional fibrin bioproducts together with photobiomodulation therapy (PBM) has potential and can improve regenerative medicine procedures. The objective of this experiment was to evaluate the effects of PBM therapy on critical size defects filled with xenogenic bone substitute associated with fibrin biopolymer. Methods: A critical defect of 8 mm was performed in 36 Wistar male adult rats that were divided into four groups. Groups BC and BC-PBM were defined as controls with defects filled by a clot (without or with PBM, respectively) and groups XS and XS-PBM that comprised those filled with biocomplex Bio-OssTM in association with fibrin biopolymer. PBM was applied immediately after the surgery and three times a week every other day, with the parameters: wavelength of 830 nm, energy density 6.2 J/cm2, output power 30 mW, beam area of 0.116 cm2, irradiance 0.258,62 W/cm2, energy/point 0.72 J, total energy 2.88 J. Fourteen and 42 days after the surgery, animals were euthanatized and subjected to microtomography, qualitative and quantitative histological analysis. Results: The BC-PBM and XS-PBM groups had a similar evolution in the tissue repair process, with a higher density of the volume of new formed bone in relation to the groups without PBM (p = 0.04086; p = 0.07093, respectively). Intense vascular proliferation and bone deposition around the biomaterial particles were observed in the animals of the groups in which biocomplex was applied (XS and XS-PBM). Conclusion: PBM therapy allowed an improvement in the formation of new bone, with a more organized deposition of collagen fibers in the defect area. Biocomplex favored the insertion and permanence of the particulate material in bone defects, creating a favorable microenvironment for accelerate repair process.

Locking compression plate fixation of critical-sized bone defects in sheep. Development of a model for veterinary bone tissue engineering

ABSTRACT Purpose To develop a segmental tibial bone defect model for tissue engineering studies in veterinary orthopedics using single locking compression plate (LCP) fixation and cast immobilization. Methods A 3-cm bone defect was created in the right tibia of 18 adult Suffolk sheep. A 10-hole, 4.5-mm LCP was applied to the dorsomedial aspect of the bone. Four locking screws were inserted into the proximal and three into the distal bone fragment. Operated limbs were immobilized with casts. Animals were submitted to stall rest, but were allowed to bear weight on the operated limb. During the recovery period, animals were checked daily for physiological parameters, behavior and lameness. Follow-up radiographs were taken monthly. Results Surgical procedures and postoperative recovery were uneventful. Animals adapted quickly to casts and were able to bear weight on the operated limb with no signs of discomfort or distress. No clinical or radiographic complications were detected over a 90-day follow-up period. Conclusions Surgical creation of tibial segmental bone defects followed by fixation with single LCP and cast immobilization was deemed a feasible and appropriate model for veterinary orthopedic research in tissue engineering.

Effect of S53P4 bioactive glass and low-level laser therapy on calvarial bone repair in rats submitted to zoledronic acid therapy

ABSTRACT Purpose To evaluate the influence of bioactive glass and photobiomodulation therapy (PBMT) in calvarial bone repair process in rats submitted to zoledronic acid therapy. Methods Twenty-four rats were selected and treated with the dose of 0.035 mg/kg of zoledronic acid every two weeks, totalizing eight weeks, to induce osteonecrosis. After the drug therapy, surgical procedure was performed to create 5-mm diameter parietal bone defects in the calvarial region. The rats were then randomly assigned to groups according to the following treatments: AZC: control group, treated with blood clot; AZBIO: bone defect filled with bioactive glass; AZL: treated with blood clot and submitted to PBMT; and AZBIOL: treated with bioactive glass S53P4 and submitted to PBMT. Tissue samples were collected and submitted to histomorphometric analysis after 14 and 28 days. Results At 14 days, bone neoformation in the AZBIO (52.15 ± 9.77) and AZBIOL (49.77 ± 13.58) groups presented higher values (p ≤ 0.001) compared to the AZC (23.35 ± 10.15) and AZL groups (23.32 ± 8.75). At 28 days, AZBIO (80.24 ± 5.41)still presented significant higher bone recovery values when compared to AZC (59.59 ± 16.92)and AZL (45.25 ± 5.41) groups (p = 0.048). In the 28-day period, the AZBIOL group didn't show statistically significant difference with the other groups (71.79 ± 29.38). Conclusions The bioactive glass is an effective protocol to stimulate bone neoformation in critical defects surgically created in rats with drug induced osteonecrosis, in the studied periods of 14 and 28 days.

Comparison of two different biomaterials in the bone regeneration (15, 30 and 60 days) of critical defects in rats

ABSTRACT Purpose To evaluate and compare two types of different scaffolds in critical bone defects in rats. Methods Seventy male Wistar rats (280 ± 20 grams) divided into three groups: control group (CG), untreated animals; biomaterial group 1 (BG1), animals that received the scaffold implanted hydroxyapatite (HA)/poly(lactic-co-glycolic) acid (PLGA); and biomaterial group 2 (BG2), animals that received the scaffolds HA/PLGA/Bleed. The critical bone defect was induced in the medial region of the skull calotte with the aid of an 8-mm-diameter trephine drill. The biomaterial was implanted in the form of 1.5 mm thick scaffolds, and samples were collected after 15, 30 and 60 days. Non-parametric Mann-Whitney test was used, with the significance level of 5% (p ≤ 0.05). Results Histology revealed morphological and structural differences of the neoformed tissue between the experimental groups. Collagen-1 (Col-1) findings are consistent with the histological ones, in which BG2 presented the highest amount of fibers in its tissue matrix in all evaluated periods. In contrast, the results of receptor activator of nuclear factor kappa-Β ligand (Rank-L) immunoexpression were higher in BG2 in the periods of 30 and 60 days, indicating an increase of the degradation of the biomaterial and the remodeling activity of the bone. Conclusions The properties of the HA/PLGA/Bleed scaffold were superior when compared to the scaffold composed only by HA/PLGA.

Platelet-concentrated and platelet poor-plasma promote different pattern on immunohistochemical expression of TGF-β1, however they impairs the osteoneogensis in calvarial defects treated with autograft due suppression of osteocalcin

ABSTRACT Purpose Herein we evaluated the effects of platelet concentrate (PC) and platelet-poor plasma (PPP) on bone repair using noncritical defects in the calvaria of rabbits and compared them to the presence of TGF-β1 and osteocalcin on reparative sites. Methods Five noncritical defects of 8.7 mm in diameter were created on the calvaria of 15 animals. Each defect was treated differently, using autograft (ABG), ABG associated with PC (ABG + PC), ABG with PPP (ABG + PPP), isolated PPP, and blood clot (control). The animals were submitted to euthanasia on the second, fourth and sixth week post-surgery. Results The defects that received ABG+PC or PPP demonstrated lower bone formation when compared to specimens that received ABG in the same period. These results coincided to significant higher immunopositivity for TGF-β1 for specimens that received PC, and lower presence of cytokine in the group PPP. However, either higher or lower presence of TGF-β1 were also correlated to lower presence of osteocalcin. Likewise, these results were similar to findings in specimens treated only with PPP when compared to control. Conclusions PC and PPP were not effective when applied in association with ABG. Similarly, isolated use of PPP was not beneficial in optimizing the bone repair.

Biological behavior of magnesium-substituted hydroxyapatite during bone repair / Comportamento biológico de hidroxiapatita substituída com magnésio durante o reparo ósseo

The aim of this study was to analyze the biological behavior and osteogenic potential of magnesium (Mg) substituted hydroxyapatite (HA) microspheres, implanted in a critical bone defect, considering that this ion is of great clinical interest, since it is closely associated with homeostasis and bone mineralization. For the purpose of this study, 30 rats were used to compose three experimental groups: GI - bone defect filled with HA microspheres; GII - bone defect filled with HA microspheres replaced with Mg; GIII - empty bone defect; evaluated at biological points of 15 and 45 days. The histological results, at 15 days, showed, in all the groups, a discrete chronic inflammatory infiltrate; biomaterials intact and surrounded by connective tissue; and bone neoformation restricted to the borders. At 45 days, in the GI and GII groups, an inflammatory response of discrete granulomatous chronic type was observed, and in the GIII there was a scarce presence of mononuclear inflammatory cells; in GI and GII, the microspheres were seen to be either intact or fragmented, surrounded by fibrous connective tissue rich in blood vessels; and discrete bone neoformation near the edges and surrounding some microspheres. In GIII, the mineralization was limited to the borders and the remaining area was filled by fibrous connective tissue. It was concluded that the biomaterials were biocompatible and osteoconductive, and the percentage of Mg used as replacement ion in the HA did not favor a greater bone neoformation in relation to the HA without the metal.(AU)

O objetivo deste estudo foi analisar o comportamento biológico de microesferas de hidroxiapatita (HA) substituída com magnésio (Mg) durante o reparo de defeito ósseo crítico, tendo em vista que este íon é de grande interesse clínico, pois está intimamente associado à homeostasia e à mineralização óssea. Para tanto, utilizou-se 30 ratos para compor três grupos experimentais: GI - defeito ósseo preenchido com microesferas de HA; GII - defeito ósseo preenchido com microesferas de HA substituída com Mg; GIII (controle) - defeito ósseo vazio; avaliados nos pontos biológicos de 15 e 45 dias. Os resultados histológicos evidenciaram, aos 15 dias, discreto infiltrado inflamatório crônico e neoformação óssea restrita às bordas, em todos os grupos. Nos grupos GI e GII, os biomateriais mantiveram-se íntegros e circundados por tecido conjuntivo frouxo. Aos 45 dias, notou-se resposta inflamatória do tipo crônica granulomatosa discreta nos grupos GI e GII, e no GIII presença escassa de células inflamatórias mononucleares. As microesferas implantadas no GI e GII mantiveram-se, em sua maioria, íntegras e envolvidas por tecido conjuntivo fibroso. Notou-se discreta neoformação óssea próxima às bordas e circunjacente a algumas microesferas. No GIII, a mineralização limitou-se às bordas e a área remanescente foi preenchida por tecido conjuntivo fibroso. Conclui-se que os biomateriais foram biocompatíveis, bioativos, osteocondutores e apresentaram biodegradação lenta, indicando seu grande potencial para em aplicações clínica como biomaterial de preenchimento.(AU)

In vitro evaluation of hydroxyapatite, chitosan, and carbon nanotube composite biomaterial to support bone healing / Avaliação in vitro do biomaterial compósito à base de hidroxiapatita, quitosana e nanotubo de carbono como adjuvante no reparo ósseo

Hydroxyapatite, chitosan, and carbon nanotube composite biomaterial were developed to improve bone healing. Previous studies suggested that a combination of biomaterials and mesenchymal stem cells (MSCs) can potentially help promote bone regeneration. In the present study, we first developed hydroxyapatite, chitosan, and carbon nanotube composite biomaterial. Then, the effect of different concentrations of the extract on the viability of Vero cells (ATCC CCL-81) and MSCs obtained from sheep bone marrow using methylthiazol tetrazolium (MTT) and propidium iodide (PI) assays were evaluated. The biomaterial group demonstrated an absence of cytotoxicity, similar to the control group. Samples with 50% and 10% biomaterial extract concentrations showed higher cell viability compared to samples from the control group (MTT assay). These results suggest that the presence of this composite biomaterial can be used with MSCs. This study also concluded that hydroxyapatite, chitosan, and carbon nanotube composite biomaterial were not cytotoxic. Therefore, these could be used for performing in vivo tests.(AU)

O compósito à base de hidroxiapatita, quitosana e nanotubo de carbono foi desenvolvido com o intuito de auxiliar na consolidação óssea. Estudos anteriores sugerem que a combinação de substitutos ósseos e células-tronco mesenquimais (CTM) podem auxiliar a potencializar e promover a regeneração óssea. No presente estudo, o biomaterial foi desenvolvido e a viabilidade e a citotoxicidade de células Vero (ATCC CCL-81) e CTM obtidas de medula óssea provenientes de ovinos utilizando ensaios metil-tiazol-tetrazólio, MTT e iodeto de propídeo (PI) foram avaliadas em diferentes concentrações de extrato desse compósito. O compósito demonstrou ausência de citotoxicidade com comportamento semelhante ao grupo controle. Amostras com 50% e 10% de concentração de extrato do compósito mostraram resultados maiores comparados ao grupo controle (ensaio MTT). Esses resultados também sugerem que a presença do biomaterial pode ser utilizada em associação a CTM. Assim, esse estudo conclui que o compósito apresentado de hidroxiapatita, quitosana e nanotubo de cabono não foi considerado citotóxico e pode ser utilizado em teste in vivo.(AU)

In vitro evaluation of hydroxyapatite, chitosan, and carbon nanotube composite biomaterial to support bone healing / Avaliação in vitro do biomaterial compósito à base de hidroxiapatita, quitosana e nanotubo de carbono como adjuvante no reparo ósseo

Hydroxyapatite, chitosan, and carbon nanotube composite biomaterial were developed to improve bone healing. Previous studies suggested that a combination of biomaterials and mesenchymal stem cells (MSCs) can potentially help promote bone regeneration. In the present study, we first developed hydroxyapatite, chitosan, and carbon nanotube composite biomaterial. Then, the effect of different concentrations of the extract on the viability of Vero cells (ATCC CCL-81) and MSCs obtained from sheep bone marrow using methylthiazol tetrazolium (MTT) and propidium iodide (PI) assays were evaluated. The biomaterial group demonstrated an absence of cytotoxicity, similar to the control group. Samples with 50% and 10% biomaterial extract concentrations showed higher cell viability compared to samples from the control group (MTT assay). These results suggest that the presence of this composite biomaterial can be used with MSCs. This study also concluded that hydroxyapatite, chitosan, and carbon nanotube composite biomaterial were not cytotoxic. Therefore, these could be used for performing in vivo tests.(AU)

O compósito à base de hidroxiapatita, quitosana e nanotubo de carbono foi desenvolvido com o intuito de auxiliar na consolidação óssea. Estudos anteriores sugerem que a combinação de substitutos ósseos e células-tronco mesenquimais (CTM) podem auxiliar a potencializar e promover a regeneração óssea. No presente estudo, o biomaterial foi desenvolvido e a viabilidade e a citotoxicidade de células Vero (ATCC CCL-81) e CTM obtidas de medula óssea provenientes de ovinos utilizando ensaios metil-tiazol-tetrazólio, MTT e iodeto de propídeo (PI) foram avaliadas em diferentes concentrações de extrato desse compósito. O compósito demonstrou ausência de citotoxicidade com comportamento semelhante ao grupo controle. Amostras com 50% e 10% de concentração de extrato do compósito mostraram resultados maiores comparados ao grupo controle (ensaio MTT). Esses resultados também sugerem que a presença do biomaterial pode ser utilizada em associação a CTM. Assim, esse estudo conclui que o compósito apresentado de hidroxiapatita, quitosana e nanotubo de cabono não foi considerado citotóxico e pode ser utilizado em teste in vivo.(AU)

Local effect of simvastatin combined with different osteoconductive biomaterials and collagen sponge on new bone formation in critical defects in rat calvaria

Purpose To evaluate the local effect of simvastatin (SVT) combined with deproteinized bovine bone (DBB) with hydroxyapatite/β-tricalcium phosphate biphasic ceramics (HA/TCP) and with collagen sponge (CS) on bone repair in critical size defects (CSDs) in rat calvaria. Methods Forty-two 5-mm diameter CSDs were made bilaterally in the calvaria of 18 rats. The animals were allocated according to the type of biomaterial and associations used to fill the CSD. After 8 weeks, the animals were euthanized, and their calvaria were evaluated for repaired tissue composition using histologic and histometric analyses. Results In the histometric analysis, the use of SVT showed to increase bone formation in the CSDs when combined with all the bone substitutes tested in this study (p<0.05). Greater bone formation was observed in the groups with SVT compared to the groups without SVT. Conclusions The use of SVT without the need for a vehicle and combined with a commercially available biomaterial may be a cheaper way to potentiate the formation of bone tissue without the need to produce new biomaterials. Therefore, SVT combined with DBB induced significantly greater new bone formation than did the other treatments.(AU)

Reconstruction of parietal bone defects with adiposederived mesenchymal stem cells: experimental study

Purpose: This study assessed the regeneration potential of mesenchymal stem cells (MSC) from adipose tissue associated with platelet-rich plasma (PRP) in bone regeneration. Methods: Thirty Wistar rats (Rattus norvegicus albinos) were divided into five groups (according to the grafting material and time to euthanasia): (1) autograft - 14 days (control), (2) autograft - 28 days (control), (3) MSC + PRP - 14 days, (4) MSC + PRP + papaverine - 14 days and (5) MSC + PRP + papaverine - 28 days. After euthanasia, the graft was removed and histological slides were prepared. They were assessed by a blinded pathologist using a previously published histological scale as parameter. Results: There was some degree of neoformed bone trabeculae (NBT) in 93.3% of the samples, as well as osteoblastic activity (OA). The autograft groups (14 and 28 days) had higher levels in the formation of bone trabeculae. Nonparametric data were analyzed using the Wilcoxon-Mann-Whitney test and proved not to be statistically significant at p 0.05. Conclusions: Experimental parietal bone reconstruction, combining MSC, PRP and papaverine presented regeneration in all groups with no significant difference among them.(AU)

Biocompatibilidade do gel de quitosana associado ao glicerol fosfato na reparação de defeitos ósseos induzidos experimentalmente no rádio de coelhos (Oryctolagus cuniculus) / [Biocompatibility of chitosan gel associated with glycerol phosphate for the healing of experimentally induced radial defects in rabbits (Oryctolagus cuniculus)]

A engenharia de tecidos caracteriza-se como ciência interdisciplinar, a qual vem desenvolvendo biomateriais para a regeneração do tecido ósseo no âmbito das medicinas humana e veterinária. O objetivo desta pesquisa foi avaliar a regeneração óssea obtida da aplicação do hidrogel de quitosana associado ao glicerol fosfato em falha óssea experimentalmente induzida no rádio de coelhos. Foram utilizados 15 coelhos adultos, distribuídos aleatoriamente em dois grupos, representados por cada um dos rádios de cada animal, sendo um grupo tratado com hidrogel de quitosana associado ao glicerol fosfato (grupo biomaterial - GB) e um grupo que não recebeu tratamento com o biomaterial (grupo controle - GC). Os animais foram avaliados radiograficamente, por densitometria óptica e análise histológica, nos períodos 30, 60 e 90 dias pós-operatórios. Houve superioridade estatística na média geral das avaliações radiográficas do GB (2,33±0,48) sobre o GC (1,77±0,06). As médias gerais de avaliação densitométrica do GB foram superiores às do GC, sendo 6,207±1,374 e 5,71±1,512, respectivamente. A avaliação histopatológica do GB foi superior à do GC nos períodos de 30, 60 e 90 dias. Assim, é possível afirmar que o hidrogel de quitosana constitui biomaterial de características desejáveis, promovendo consolidação óssea mais rápida e eficiente, sem causar reações adversas.(AU)

Tissue engineering is an interdisciplinary science that has been developing biomaterials for bone regeneration in medicine and veterinary medicine, following an imminent need. The aim of this study was to evaluate bone regeneration after use of chitosan hydrogel associated with glycerol phosphate in experimentally induced bone gap in the radius of rabbits. Fifteen adult rabbits were randomly distributed in two experimental groups, represented by each radius of every single animal. The animals in the Biomaterial Group (GB) were treated with a glycerol phosphate-associated chitosan hydrogel and in the Control Group (GC) they received no treatment with the biomaterial. The animals were evaluated clinically, radiographically, histologically and by optic densitometry at 30, 60 and 90 days postoperatively. There was statistical superiority in the general average of the radiographic estimates of GB (2.33 ± 0.48) over the CG (1.77 ± 0.06). The general averages of GB densitometric evaluation were higher than the CG, being 6.207 ± 1.374 and 5.71 ± 1.512, respectively. Histopathological evaluation of GB was superior to CG in periods of 30, 60 and 90 days. Chitosan hydrogel constitutes a biomaterial of desired characteristics, promoting faster and more efficient bone repair when compared to GC.(AU)

Biological behavior of magnesium-substituted hydroxyapatite during bone repair

Abstract The aim of this study was to analyze the biological behavior and osteogenic potential of magnesium (Mg) substituted hydroxyapatite (HA) microspheres, implanted in a critical bone defect, considering that this ion is of great clinical interest, since it is closely associated with homeostasis and bone mineralization. For the purpose of this study, 30 rats were used to compose three experimental groups: GI - bone defect filled with HA microspheres; GII - bone defect filled with HA microspheres replaced with Mg; GIII - empty bone defect; evaluated at biological points of 15 and 45 days. The histological results, at 15 days, showed, in all the groups, a discrete chronic inflammatory infiltrate; biomaterials intact and surrounded by connective tissue; and bone neoformation restricted to the borders. At 45 days, in the GI and GII groups, an inflammatory response of discrete granulomatous chronic type was observed, and in the GIII there was a scarce presence of mononuclear inflammatory cells; in GI and GII, the microspheres were seen to be either intact or fragmented, surrounded by fibrous connective tissue rich in blood vessels; and discrete bone neoformation near the edges and surrounding some microspheres. In GIII, the mineralization was limited to the borders and the remaining area was filled by fibrous connective tissue. It was concluded that the biomaterials were biocompatible and osteoconductive, and the percentage of Mg used as replacement ion in the HA did not favor a greater bone neoformation in relation to the HA without the metal.

Resumo O objetivo deste estudo foi analisar o comportamento biológico de microesferas de hidroxiapatita (HA) substituída com magnésio (Mg) durante o reparo de defeito ósseo crítico, tendo em vista que este íon é de grande interesse clínico, pois está intimamente associado à homeostasia e à mineralização óssea. Para tanto, utilizou-se 30 ratos para compor três grupos experimentais: GI - defeito ósseo preenchido com microesferas de HA; GII - defeito ósseo preenchido com microesferas de HA substituída com Mg; GIII (controle) - defeito ósseo vazio; avaliados nos pontos biológicos de 15 e 45 dias. Os resultados histológicos evidenciaram, aos 15 dias, discreto infiltrado inflamatório crônico e neoformação óssea restrita às bordas, em todos os grupos. Nos grupos GI e GII, os biomateriais mantiveram-se íntegros e circundados por tecido conjuntivo frouxo. Aos 45 dias, notou-se resposta inflamatória do tipo crônica granulomatosa discreta nos grupos GI e GII, e no GIII presença escassa de células inflamatórias mononucleares. As microesferas implantadas no GI e GII mantiveram-se, em sua maioria, íntegras e envolvidas por tecido conjuntivo fibroso. Notou-se discreta neoformação óssea próxima às bordas e circunjacente a algumas microesferas. No GIII, a mineralização limitou-se às bordas e a área remanescente foi preenchida por tecido conjuntivo fibroso. Conclui-se que os biomateriais foram biocompatíveis, bioativos, osteocondutores e apresentaram biodegradação lenta, indicando seu grande potencial para em aplicações clínica como biomaterial de preenchimento.

A critical size defect model in the radius of rabbits / Modelo de falha óssea segmentar em rádio de coelhos

This study aimed to characterize a preclinical model of critical size defect (CSD) in the radius of rabbits.Twenty adults (> 7 months), female, New Zealand Rabbits, weighing between 3,5 to 5 Kg were used. They underwent a 1.5 cm long ostectomy of the diaphysis of the radius, starting 2 cm from the carpus joint. Radiographic analyses were performed at 15, 30, 60, and 90 days postoperatively, in order to evaluated bone callus formation, periosteal reaction, and bone bridge formation.The methodology allowed to precisely create bone defects of 1.5cm. Over time, no bone deposition was found at 15 days, but mild bone callus formation was observed in three animals after 60 days postoperative. At 90 days postoperatively only one rabbit presented bone consolidation radiographically, the others presented non-union. The critical bone defect proposed in this study was satisfactory, feasible with very low risk of complications.

O objetivo do presente estudo é caracterizar um modelo pré-clínico de falha óssea crítica em rádio de coelhos. Vinte coelhos adultos (> 7 meses), fêmeas, da raça New Zealand, pesando entre 3,5 e 5 kg foram utilizados. Os animais foram submetidos à ostectomia segmentar de 1,5 cm na diáfise do rádio, iniciando 2 cm acima da articulação carpo radial. As análises radiográficas foram feitas aos 15, 30, 60 e 90 dias pós-operatório, para avaliação de formação de calo ósseo, reação periosteal e formação de ponte óssea. nA metodologia permitiu a criação precisa de defeitos ósseo segmentar de 1,5 cm. Durante o experimento, não se observou deposição óssea na primeira avaliação radiográfica, porém após 60 dias foi possível visibilizar formação de calo ósseo em 3 animais. Aos 90 dias apenas um animal apresentou consolidação óssea radiograficamente; o restante apresentou não-união óssea. A falha óssea foi eficaz para estabelecer um defeito ósseo crítico além de apresentar fácil aplicação, apresentando pequeno índice de complicação.

A critical size defect model in the radius of rabbits / Modelo de falha óssea segmentar em rádio de coelhos

This study aimed to characterize a preclinical model of critical size defect (CSD) in the radius of rabbits.Twenty adults (> 7 months), female, New Zealand Rabbits, weighing between 3,5 to 5 Kg were used. They underwent a 1.5 cm long ostectomy of the diaphysis of the radius, starting 2 cm from the carpus joint. Radiographic analyses were performed at 15, 30, 60, and 90 days postoperatively, in order to evaluated bone callus formation, periosteal reaction, and bone bridge formation.The methodology allowed to precisely create bone defects of 1.5cm. Over time, no bone deposition was found at 15 days, but mild bone callus formation was observed in three animals after 60 days postoperative. At 90 days postoperatively only one rabbit presented bone consolidation radiographically, the others presented non-union. The critical bone defect proposed in this study was satisfactory, feasible with very low risk of complications.(AU)

O objetivo do presente estudo é caracterizar um modelo pré-clínico de falha óssea crítica em rádio de coelhos. Vinte coelhos adultos (> 7 meses), fêmeas, da raça New Zealand, pesando entre 3,5 e 5 kg foram utilizados. Os animais foram submetidos à ostectomia segmentar de 1,5 cm na diáfise do rádio, iniciando 2 cm acima da articulação carpo radial. As análises radiográficas foram feitas aos 15, 30, 60 e 90 dias pós-operatório, para avaliação de formação de calo ósseo, reação periosteal e formação de ponte óssea. nA metodologia permitiu a criação precisa de defeitos ósseo segmentar de 1,5 cm. Durante o experimento, não se observou deposição óssea na primeira avaliação radiográfica, porém após 60 dias foi possível visibilizar formação de calo ósseo em 3 animais. Aos 90 dias apenas um animal apresentou consolidação óssea radiograficamente; o restante apresentou não-união óssea. A falha óssea foi eficaz para estabelecer um defeito ósseo crítico além de apresentar fácil aplicação, apresentando pequeno índice de complicação.(AU)

Matriz porosa do BV60S associada a células osteoprogenitoras alógenas no tratamento de defeitos ósseos críticos em rádios de cães / Porous matrix of BG60S associated with allogenic osteoprogenitor cells in the treatment of critical bone defects in the radius of dogs

O objetivo do estudo foi avaliar o efeito da matriz porosa do biovidro 60S (BV60S) associada a células osteoprogenitoras (CO) alógenas no tratamento de defeitos ósseos críticos de cães. Foram utilizados 20 cães, machos, sem raça definida, com dois anos de idade e massa corporal média de 25kg. Com os cães sob anestesia geral, foram criados defeitos ósseos críticos no terço médio dos ossos rádios. Procedeu-se à fixação óssea com uma placa em ponte, e os defeitos foram tratados de acordo com cada grupo experimental. Constituíram-se três grupos experimentais, em que os defeitos ósseos foram preenchidos com: BV60S associado a CO alógenas (grupo BV60S+CO), osso autógeno (grupo C+), ou não preenchidos (grupo C-). A regeneração óssea foi avaliada por meio de exames radiográficos, densitométricos e histomorfométricos ao longo de 90 dias. Os grupos C- e BV60S+CO mostraram preenchimento ósseo parcial do defeito de, no máximo, 56,68% e 35,23%, respectivamente, sem a formação de ponte óssea entre as extremidades, e o controle positivo (C+) mostrou regeneração óssea completa. Conclui-se que a matriz porosa do BV60S associada às células osteoprogenitoras não é eficiente no tratamento de defeitos ósseos críticos em rádios de cães.(AU)

The objective of this study was to evaluate the effect of the porous matrix of bioglass 60S (BV60S) associated with allogenic osteoprogenitor cells (CO) in the treatment of critical bone defects of dogs. 20 male mongrel dogs at two years old and mean weight of 25kg were used. Dogs were anesthetized and critical bone defects were created in the middle third of the radios bones. With dogs under general anesthesia, critical bone defects were created in the middle third of bone radios. Bone fixation was done with a bridge plate and defects treated according to each experimental group. Three experimental groups were formed according to the treatment. The defects filled with BV60S associated with allogenic CO (Group-BV60S+CO), autogenous bone (Group-C+) or unfilled (Group-C-). Bone regeneration was evaluated by radiography, bone densitometry and histomorphometry over 90 days. The BV60S+CO and C- groups showed partial bone filling of the defect of at most 56.68% and 35.23%, respectively. No bone bridge formation was observed between the extremities in the BV60S+CO and C- groups. Positive control showed complete bone regeneration at 90 days. It was concluded that the porous matrix of BV60S associated with osteoprogenitor cells was not effective in the treatment of critical bone defects in the radius of dogs.(AU)

Fibrin biopolymer as scaffold candidate to treat bone defects in rats

Bone tissue repair remains a challenge in tissue engineering. Currently, new materials are being applied and often integrated with live cells and biological scaffolds. The fibrin biopolymer (FBP) proposed in this study has hemostatic, sealant, adhesive, scaffolding and drug-delivery properties. The regenerative potential of an association of FBP, biphasic calcium phosphate (BCP) and mesenchymal stem cells (MSCs) was evaluated in defects of rat femurs. Methods: Adult male Wistar rats were submitted to a 5-mm defect in the femur. This was filled with the following materials and/or associations: BPC; FBP and BCP; FBP and MSCs; and BCP, FBP and MSCs. Bone defect without filling was defined as the control group. Thirty and sixty days after the procedure, animals were euthanatized and subjected to computed tomography, scanning electron microscopy and qualitative and quantitative histological analysis. Results: It was shown that FBP is a suitable scaffold for bone defects due to the formation of a stable clot that facilitates the handling and optimizes the surgical procedures, allowing also cell adhesion and proliferation. The association between the materials was biocompatible. Progressive deposition of bone matrix was higher in the group treated with FBP and MSCs. Differentiation of mesenchymal stem cells into osteogenic lineage was not necessary to stimulate bone formation. Conclusions: FBP proved to be an excellent scaffold candidate for bone repair therapies due to application ease and biocompatibility with synthetic calcium-based materials. The satisfactory results obtained by the association of FBP with MSCs may provide a more effective and less costly new approach for bone tissue engineering.(AU)

Matriz porosa do BV60S associada a células osteoprogenitoras alógenas no tratamento de defeitos ósseos críticos em rádios de cães / Porous matrix of BG60S associated with allogenic osteoprogenitor cells in the treatment of critical bone defects in the radius of dogs

O objetivo do estudo foi avaliar o efeito da matriz porosa do biovidro 60S (BV60S) associada a células osteoprogenitoras (CO) alógenas no tratamento de defeitos ósseos críticos de cães. Foram utilizados 20 cães, machos, sem raça definida, com dois anos de idade e massa corporal média de 25kg. Com os cães sob anestesia geral, foram criados defeitos ósseos críticos no terço médio dos ossos rádios. Procedeu-se à fixação óssea com uma placa em ponte, e os defeitos foram tratados de acordo com cada grupo experimental. Constituíram-se três grupos experimentais, em que os defeitos ósseos foram preenchidos com: BV60S associado a CO alógenas (grupo BV60S+CO), osso autógeno (grupo C+), ou não preenchidos (grupo C-). A regeneração óssea foi avaliada por meio de exames radiográficos, densitométricos e histomorfométricos ao longo de 90 dias. Os grupos C- e BV60S+CO mostraram preenchimento ósseo parcial do defeito de, no máximo, 56,68% e 35,23%, respectivamente, sem a formação de ponte óssea entre as extremidades, e o controle positivo (C+) mostrou regeneração óssea completa. Conclui-se que a matriz porosa do BV60S associada às células osteoprogenitoras não é eficiente no tratamento de defeitos ósseos críticos em rádios de cães.(AU)

The objective of this study was to evaluate the effect of the porous matrix of bioglass 60S (BV60S) associated with allogenic osteoprogenitor cells (CO) in the treatment of critical bone defects of dogs. 20 male mongrel dogs at two years old and mean weight of 25kg were used. Dogs were anesthetized and critical bone defects were created in the middle third of the radios bones. With dogs under general anesthesia, critical bone defects were created in the middle third of bone radios. Bone fixation was done with a bridge plate and defects treated according to each experimental group. Three experimental groups were formed according to the treatment. The defects filled with BV60S associated with allogenic CO (Group-BV60S+CO), autogenous bone (Group-C+) or unfilled (Group-C-). Bone regeneration was evaluated by radiography, bone densitometry and histomorphometry over 90 days. The BV60S+CO and C- groups showed partial bone filling of the defect of at most 56.68% and 35.23%, respectively. No bone bridge formation was observed between the extremities in the BV60S+CO and C- groups. Positive control showed complete bone regeneration at 90 days. It was concluded that the porous matrix of BV60S associated with osteoprogenitor cells was not effective in the treatment of critical bone defects in the radius of dogs.(AU)

Fibrin biopolymer as scaffold candidate to treat bone defects in rats

Background:Bone tissue repair remains a challenge in tissue engineering. Currently, new materials are being applied and often integrated with live cells and biological scaffolds. The fibrin biopolymer (FBP) proposed in this study has hemostatic, sealant, adhesive, scaffolding and drug-delivery properties. The regenerative potential of an association of FBP, biphasic calcium phosphate (BCP) and mesenchymal stem cells (MSCs) was evaluated in defects of rat femurs.Methods:Adult male Wistar rats were submitted to a 5-mm defect in the femur. This was filled with the following materials and/or associations: BPC; FBP and BCP; FBP and MSCs; and BCP, FBP and MSCs. Bone defect without filling was defined as the control group. Thirty and sixty days after the procedure, animals were euthanatized and subjected to computed tomography, scanning electron microscopy and qualitative and quantitative histological analysis.Results:It was shown that FBP is a suitable scaffold for bone defects due to the formation of a stable clot that facilitates the handling and optimizes the surgical procedures, allowing also cell adhesion and proliferation. The association between the materials was biocompatible. Progressive deposition of bone matrix was higher in the group treated with FBP and MSCs. Differentiation of mesenchymal stem cells into osteogenic lineage was not necessary to stimulate bone formation.Conclusions:FBP proved to be an excellent scaffold candidate for bone repair therapies due to application ease and biocompatibility with synthetic calcium-based materials. The satisfactory results obtained by the association of FBP with MSCs may provide a more effective and less costly new approach for bone tissue engineering.(AU)