Abstract A new animal model was developed to evaluate the effect of bovine native bone morphogenetic protein (BMP) on the healing of segmental, critical-sized bone defects. Laboratory-bred adult beagle dogs were used in the study. A 2 cm corticoperiosteal defect was created using an oscillating saw in mid-ulna, and the defect was treated with bone grafts and implants fixed by an intramedullary Kirschner wire through predrilled holes in the middle of the implant. Plate and screw fixation was also used in some groups. Coral, hydroxyapatite and demineralized xenograft bone were placed in the defects with or without BMP. Autografts and allografts were used as controls. The BMP was extracted from bovine diaphyseal bone. The follow-up period was 36 weeks. Radiographs were taken at regular intervals during the follow-up period, and bone formation and bone union were evaluated. The radiographs were digitized, and callus was measured and CT scans obtained to define bone density. At the end of the study, the bones were harvested and tested mechanically in a torsion machine until failure. After mechanical testing, the bones were reconstructed and histological sections were made. With autograft and allograft bone grafts, healing was nearly complete. Hydroxyapatite and demineralized xenograft bone did not result in healing of the bone defect, while coral enhanced bone formation, but the healing was not comparable to autografts or allografts. Hydroxyapatite implants did not resorb during the 36 weeks of follow-up to enhance bone healing, and there was a fibrous capsule around the hydroxyapatite implants in histology. Xenograft bone was resorbed, and very little bone formation and extensive fibrosis were seen at the implant site. Coral was resorbed and gradually replaced by new bone, but did not heal the defect completely. With every implant, added BMP had a positive effect on healing as evaluated either radiographically, mechanically or histologically. Coral was the most optimal carrier material for BMP among the materials tested in this study. The animal model seems to be suitable for studying the healing of bone defects, as all the animals were physically active from the first postoperative day and did not seem to have problems with motion during the follow-up period. Intramedullary fixation lacks rotational stability, which may have a negative effect on healing. The bones fixed with a plate and screws showed better scores in radiographs and were mechanically stronger, although the study groups were too small to allow definitive conclusions. As a conclusion, none of the transplants or implants were equally efficient as cortical autograft in healing segmental ulnar defects. BMP did not enhance the poor capacity of hydroxyapatite and xenograft bone to heal the bone defect. According to the present findings, the composite implant consisting of coral and BMP seemed to be the best of the composite implants tested.

AIM & HYPOTHESIS: Resolvins, derived from omega-3 fatty acids, may actively resolve inflammation. Resolvin E1 (RvE1) binds to Chem-R23 as an endogenous anti-inflammatory and pro-resolving lipid mediator. We hypothesized that RvE1 may also activate osteoblasts to restore critical size bone defects in a calvarial model. MATERIALS & METHODS: An in-vitro calvarial culture system was used to evaluate the stimulative effects of RvE1 compared to Amniotic Growth Factor (AGF) (a known stimulant in this system) on critical size defects under static conditions. Calvaria harvested from 10 mice and separated into 20 calvaria halves were cultured under conditions favoring bone formation. The test groups were defect only, defect plus a collagen membrane, defect plus a collagen membrane plus RvE1, and defect plus a collagen membrane plus AGF. The effect of RvE1 and AGF on healing of a critical size bone defect was assessed with both histological evaluation and alkaline phosphatase assays. RESULTS: RvE1 binds in a receptor-ligand interaction with Chem-R23 in the periosteum to stimulate cellular proliferation and migration into a critical size bone defect of neonatal mouse calvaria. CONCLUSION: These results suggest that RvE1 has a direct effect on osteoblast activity at and around the edge of a critical size 2 mm defect without an inflammatory reaction.

Die Entwicklung innovativer Therapiekonzepte für die Knochenregeneration erfordert validierte segmentale Knochendefekt-Tiermodelle. Dabei ist das Mausmodell für die präklinische Testung von zentraler Bedeutung, jedoch fehlen in der wissenschaftlichen Literatur bislang Angaben zu validierten, extern stabilisierenden kritischen segmentalen Knochendefektmodellen an der immundefizienten Maus. Das Ziel dieser Arbeit war daher die Entwicklung und in vivo Evaluierung eines zuverlässigen und einfach zu handhabenden Modells für extern stabilisierte kritische Knochendefekte an der immundefizienten Maus. Dreißig männliche nu/nu-Mäuse (40,7±2,8 g, 95±2,6 d) wurden mittels Isofluraninhalation narkotisiert und anschließend ein externer Fixateur (MouseExFix, RISystem, AO Research Institute Davos, Schweiz) am rechten Femur angebracht. Femorale Knochendefekte der Länge 1 mm (n=10), 2 mm (n=10) und 3 mm (n=10) wurden erzeugt. Der Wundverschluss erfolgte mit Einzelknopfnähten. Röntgenaufnahmen wurden unmittelbar postoperativ und im Folgenden alle zwei Wochen innerhalb des Beobachtungszeitraums von zwölf Wochen angefertigt und im Hinblick auf Knochenregeneration und –fusion ausgewertet. Weiterhin wurden histomorphologische, histomorphometrische, immunhistochemische und µCT-Analysen zur dreidimensionalen und zellulären Beurteilung der Knochenheilung angefertigt. Alle Tiere überlebten die Operation. Sechs Tiere starben innerhalb des Beobachtungszeitraums als Folge von starkem Blutverlust (n=1), Infektion (n=1), Pinlockerung, welche die Euthanasie erforderlich machte (n=2) und durch Komplikationen bei der Anästhesie (n=2). Die µCT-Analyse nach zwölf Wochen zeigte, dass 3/8 der 1 mm-Defekte, 5/8 der 2 mm-Defekte und 8/8 der 3 mm-Defekte eine Pseudarthrose aufwiesen. Das mittlere Defektvolumen stieg signifikant (p<0,001) mit der Größe des Defektes und betrug 0,36±0,42 mm³ (1 mm-Gruppe), 1,4±0,88 mm³ (2 mm-Gruppe), bzw. 2,88±0,28 mm³ (3 mm-Gruppe). Die mittlere Defektgröße verringerte sich entsprechend um 77,6% (1 mm-Gruppe), 56,8% (2 mm-Gruppe), bzw. 28,6% (3 mm-Gruppe). Die histomorphologischen, histomorphometrischen und immunhistochemischen Analysen zeigten keine statistisch signifikanten Unterschiede zwischen den drei experimentellen Gruppen. Das verwendete MouseExFix-System ist ein zuverlässiges und einfach zu handhabendes Verfahren zur Stabilisierung eines kritischen segmentalen Knochendefekts an der immundefizienten Maus, wenn ein 3 mm-Defekt erzeugt wird. Das im Rahmen der Studie entwickelte und validierte murine extern stabilisierte, segmentale kritische Knochendefektmodell ermöglicht die präklinische Evaluierung von Konzepten zur lokalen Knochenregeneration inklusive der Verwendung allo- und xenogener Zellen. / The development of innovative therapies for bone regeneration requires the use of advanced site-specific bone defect small animal models. In this context, murine models are of major importance as they allow for sufficient sample sizes prior to preclinical testing using larger animals. Owing to the small dimensions of the murine femur only a few custom fabricated fixation devices have been described in the literature so far. The aim of this investigation was to develop and validate a new, externally fixated critical size bone defect model for immunodeficient mice. Thirty male nu/nu mice (40.7 ± 2.8 g, 95 ± 2.6 days old) were anesthetized by isoflurane inhalation and an external fixation device (MouseExFix, RISystem, AO Research Institute Davos, Switzerland) was attached to the right femur. Femoral bone defects of 1 mm (n=10), 2 mm (n=10) and 3 mm (n=10) were created. Wounds were closed without any additional treatment. X-ray films obtained immediately after surgery and every 2 weeks postoperatively during the 12 week postoperative observation period were evaluated for bony regeneration and fusion. Furthermore, histomorphology, histomorphometry, immunohistochemistry and µCT analysis were performed. All of the animals survived the operation. Twenty four out of 30 animals reached the twelfth postoperative week. µCT analyses after twelve weeks showed that 3/8 of the 1 mm defects, 5/8 of the 2 mm defects and 8/8 of the 3 mm defects remained as nonunions. The defect volume was 0.36 ± 0.42 mm³ (1 mm group), 1.40 ± 0.88 mm³ (2 mm group), and 2.88 ± 0.28 mm³ (3 mm group) (p<0.001, between all groups). The defect size decreased by 77.6% (1-mm group), 56.8% (2-mm group) and 28.6% (3-mm group) (p=0.152, between all groups). Our method using the MouseExFix device has proven to be a reliable and easy-to-handle external fixation system for the stabilization of critical-size segmental bone defects in immundeficient mice when 3 mm defects are generated. This mouse model allows for high-throughput translational evaluation of concepts for site-specific bone regeneration including strategies using allogenic and xenogenic cell types.

Orientador: Sheila Canevese Rahal / Resumo: O presente estudo visou avaliar temporalmente a formação e a qualidade da membrana induzida de Masquelet, tendo por modelo uma falha óssea segmentar induzida no rádio de galinhas. Foram utilizadas 16 galinhas saudáveis, com um ano de idade e massa corpórea média de 1,45 kg. Sob anestesia geral inalatória, foi induzido defeito segmentar de 1,5 cm no rádio esquerdo, o qual foi preenchido com cimento ósseo na fase pastosa. Os defeitos foram avaliados por meio de exames radiográficos e ultrassonográficos, imediatamente após o procedimento cirúrgico e aos sete, 15, 21 e 30 dias de pós-operatório. Para a avaliação histológica das membranas induzidas, uma ave foi submetida à eutanásia aos sete dias (estudo piloto) de pós-operatório e cinco aves aos 15, 21 e 30 dias de pós-operatório. No exame radiográfico do pós-operatório imediato foi possível verificar a presença do cimento ocupando a falha óssea segmentar, como uma massa radiopaca, com variações de intensidade. Com 30 dias de pós-operatório já foi evidente a presença de nova formação óssea partindo de ambas as extremidades fraturadas. Pelo exame ultrassonográfico, as membranas mostraram a maior formação de vascularização aos 30 dias de pós-operatório. Pela avaliação histológica a membrana aos sete e 15 dias de pós-operatório tinha três zonas distintas, porém aos 15 dias havia presença de neovascularização, fibras colágenas organizadas e diminuição de células inflamatórias. Aos 21 dias após a cirurgia houve uma perda de delimitaçã... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This study aimed to evaluate the formation and quality of the induced membrane in Masquelet's technique, using a segmental bone defect induced in the chicken’s radius. Sixteen healthy domestic chickens, 1 year old and weighing 1.45 kg were used. Under general anesthesia, a 1.5-cm segmental bone defect was induced in the left radius, which was filled with bone cement during its pasty polymerization phase. The bone defects were evaluated by plain X-rays and ultrasounds, immediately after surgery and at seven, 15, 21 and 30 days postoperatively. One bird was euthanized at 7 days after surgery (pilot study), and five birds were euthanized at 15, 21 and 30 days postoperatively for histological evaluation of the induced membranes. Immediate postoperative radiographic examination showed the presence of cement that occupied the segmental bone defect, as a radiopaque mass, with intensity variations. Thirty days after surgery the presence of new bone formation at the fractured extremities was evident. Ultrasound evaluation showed that the induced-membrane had the highest rate of vascularization at 30 days post-surgery. Histologically, the induced-membrane had three distinct zones at 7 and at 15 days postoperatively, but day 15 had neovascularization, organized collagen fibers and reduced of inflammatory cells. At 21 days after surgery, the zones were less defined and there was cartilage and bone metaplastic areas. At 30 days postoperative diffuse mineralization of the membrane was obse... (Complete abstract click electronic access below) / Mestre

A não-união óssea devido a condições pós-traumáticas ou patologias apresentam grandes desafios para a prática ortopédica, onde a necessidade de analisar novos biomateriais que auxiliem no processo da regeneração, tem levado vários pesquisadores a estudarem a membrana do látex natural (LN) e colágeno (COL) como formas de tratamento através da regeneração óssea guiada. O uso do LN têm mostrado promissores resultados em aplicações biomédicas, apresentando características como biocompatibilidade, crescimento ósseo e estímulo natural à angiogênese. Estudos que utilizam as membranas de colágeno para a mesma finalidade também observaram bons resultados em relação à biocompatibilidade, função hemostática, poder de auxiliar na cicatrização de feridas, capacidade de estimular a adesão celular e quimiotaxia. Porém, possuem alto poder de se degradar antes de completar o período final de tratamento. Desta forma, a utilização de membranas contendo estes dois componentes pode auxiliar no processo de neoformação óssea através da regeneração óssea guiada (ROG), e o LN pode funcionar como matriz para a liberação controlada do colágeno no defeito. Portanto, o objetivo deste estudo foi avaliar o efeito da membrana mista, composta por LN/COL, no processo de reparação óssea em defeitos de tíbia de ratos. Para tanto, foram utilizados quarenta (40) ratos machos da raça Rattus norvegicus albinus, da variedade Wistar, com cinco semanas de idade e peso médio de 300 g. Foi realizado um defeito ósseo bilateralmente nas tíbias de todos os animais, que foram divididos em 4 grupos (n=10), sendo: grupo controle (C); e tratados: grupo látex natural (LN); grupo látex natural/colágeno (LN/COL) e grupo colágeno (COL). O tempo de tratamento foi de 42 dias e a eutanásia dos animais foi realizada por overdose de anestésico (ketamina/xilazina). Após a eutanásia, as tíbias de cada animal foram dissecadas e limpas das partes moles, e armazenadas de acordo com protocolo de cada análise. Foram realizadas análise de microtomografia computadorizada (micro CT), densitometria, ensaio mecânico, histologia, e reação de polimerização em cadeia quantitativo (RT-qPCR). A análise estatística dos dados foi realizada utilizando o programa SPSS® (Versão 20.0, IBM®, Armonk, EUA) e foi adotado nível de significância de 5% (p<= 0,05). Foi utilizado o teste de Shapiro-Wilk para testar se os dados apresentavam ou nãodistribuição normal. A comparação entre os grupos (dados paramétricos) foi realizada através do teste ANOVA com pós-teste de Tukey. Os dados não-paramétricos foram analisados através do teste de Kruskal-Wallis. Foram demonstradas diferenças estatísticas no BV entre os grupos LN e CON (p<0,008); BV/TV do grupo LN/COL comparado ao CON (p<0,016) e ao LN (p<0,016); na neoformação óssea entre CON e COL (p< 0,002); e na força máxima quando comparado o grupo COL com CON (p<0,050) e (p<0,001). Os resultados demonstraram que não houve diferença significativa entre os grupos na análise da DMO (p=0,669), colágeno (p=0,224), rigidez relativa (p=0,461), RANK L (p=0,121), OC (p=0,066) e OPG (0,287), porém, todas as membranas utilizadas demonstraram valores superiores ao grupo CON. Sendo assim podemos concluir que as membranas utilizadas como tratamento apresentaram eficácia na reparação óssea de tíbia de ratos, no entanto, as membranas de COL e LN/COL demonstraram resultados mais significativos no período analisado. / The non-union of bone due to post-traumatic conditions or pathologies presents major challenges for orthopedic practice, where the need to analyze new biomaterials that aid in the regeneration process, has led several researchers to study the natural latex (LN) membrane and collagen (COL) as forms of treatment through guided bone regeneration. The use of LN has shown promising results in biomedical applications, presenting characteristics such as biocompatibility, bone growth and natural stimulation to angiogenesis. Studies that use collagen membranes for the same purpose have also observed good results in relation to biocompatibility, hemostatic function, the power to aid wound healing, the ability to stimulate cell adhesion and chemotaxis. However, they have a high capacity to degrade before completing the final treatment period. Thus, the use of membranes containing these two components can aid in the bone neoformation process through guided bone regeneration (ROG), and the LN can function as a matrix for the controlled release of the collagen in the defect. Therefore, the objective of this study was to evaluate the effect of the mixed membrane, composed of LN / COL, in the process of bone repair in rat tibia defects. For this purpose, forty (40) male Rattus norvegicus albinus rats of the Wistar variety, with five weeks of age and average weight of 300 g were used. A bone defect was performed bilaterally in the tibiae of all the animals, which were divided into 4 groups (n = 10), being: control group (C); and treated: natural latex group (LN); natural latex / collagen group (LN / COL) and collagen group (COL). The treatment time was 42 days and euthanasia of the animals was performed by anesthetic overdose (ketamine / xylazine). After euthanasia, the tibia from each animal were dissected and cleaned from the soft tissues, and stored according to each analysis protocol. Computed microtomography (micro CT), densitometry, mechanical assay, histology, and quantitative polymerization (RT-qPCR) were performed. Statistical analysis of the data was performed using the SPSS® program (Version 20.0, IBM®, Armonk, USA) and a significance level of 5% was adopted (p<=0.05). The Shapiro-Wilk test was used to test whether or not the data presented normal distribution. The comparison between the groups (parametric data) was performed through the ANOVA test with Tukey post-test. Nonparametric data were analyzed using the Kruskal-Wallis test. Statistical differences in BVwere found between the LN and CON groups (p <0.008); BV / TV of the LN / COL group compared to the CON (p <0.016) and the LN (p <0.016); in the bone neoformation between CON and COL (p <0.002); and maximal strength when compared to the COL group with CON (p <0.050) and (p <0.001). The results showed that there was no significant difference between groups in the analysis of BMD (p = 0.669), collagen (p = 0.224), relative rigidity (p = 0.461), RANK L (p = and OPG (0.287), however, all the membranes used showed higher values than the CON group. Thus, it can be concluded that the membranes used as treatment showed efficacy in rat tibia repair, however, the COL and LN / COL membranes showed more significant results in the analyzed period.

Nos equinos as fraturas geralmente são de alta energia provocando perda do tecido ósseo. Estas lesões do tecido ósseo ocorrem quando suas propriedades de resistência e rigidez são ultrapassadas. Devido a perda de tecido ósseo diversos métodos são utilizados para corrigir os defeitos ósseos, tanto em ortopedia humana, quanto na medicina veterinária, porém os resultados muitas vezes não são satisfatórios. O desenvolvimento de compostos a base colágeno, quitosana e hidroxiapatita deu-se devido a busca na melhora do comportamento mecânico e biológico dos enxertos. O objetivo deste estudo foi avaliar o comportamento biomecânico do osso III/IV metacarpianos de ovinos após a implantação de compósito de quitosana, hidroxiapatita e colágeno. Foi utilizado seis ovinos fêmeas da raça Santa Inês, os quais foram submetidos à ostectomias unicorticais de cinco milímetros de diâmetro na região média da superfície dorsal do III/IV metacarpianos. Posteriormente, através de sorteio, foi implantado o compósito de quitosana, colágeno e hidroxiapatita em um membro torácico. No membro contralateral foi reproduzida a mesma técnica, porém foi mantido como controle, não sendo preenchido com o compósito. Todos os animais foram submetidos à avaliação física diária. Após 180 dias da criação da falha, os ovinos foram eutanasiados com protocolo autorizado pela Comissão de Ética no Uso de Animais. Os ossos foram dissecados e armazenados á 20&ordm; C. Após o descongelamento completo, as amostras foram submetidas a ensaio de flexão em três pontos realizado em máquina universal de ensaios mecânicos KRATOS&reg;, modelo KE3000MP, software: TRACOMP W95. Os ossos foram posicionados com sua superfície palmar (mais plana) apoiada sobre duas bases cônicas distantes 5 cm entre sí, de modo que a falha óssea ficasse posicionada à mesma distância entre as bases. A carga foi aplicada na superfície dorsal por um atuador cônico no ponto médio do osso, onde foram criadas as falhas ósseas, com velocidade de deslocamento de 5 milímetros por minuto até o momento da fratura do osso. Durante o ensaio mecânico o software gerou gráficos de força x deformação, de onde foram calculadas as seguintes propriedades biomecânicas: força máxima, rigidez, momento e deformação máxima. Através da análise estatística não houve diferença estatísticas na análise da rigidez, força máxima, momento e deformação máxima para ambos os grupos. Com estes resultados podemos concluir que o compósito de quitosana, hidroxiapatita e colágeno não interferiu na consolidação óssea de III/IV metacarpianos de ovinos após 180 dias da implantação. / In equines, the fractures are usually of high energy causing loss of bone tissue. These bone tissue injuries occur when its properties of strength and rigidity are outdated. Due to bone loss, various methods are used to correct the bone defects, both in human and in orthopedic veterinary medicine, but the results often are not satisfactory. The development of chitosan, collagen and hydroxyapatite composite came about due to search the improvement of the mechanical behaviour and biological grafts. The objective of this study was to evaluate the biomechanical behavior of the III/IV metacarpal bone of sheep after the implantation of chitosan, collagen and hydroxyapatite composite. Six healthy female sheep Santa Inês breed were submitted to bilateral unicortical ostectomy (five mm/diameter) on the dorsal aspect of the III/IV metacarpal bone. One front limb was randomly selected for composite implatation. At the contralateral limb was reproduced the same technique, but was kept as control, and are not filled with composite. The animals were submitted to daily physical examination during 180-day follow-up period. After 180 days of failure creation, the animals were euthanized with protocol approved by the Animal Ethics Committee. The bones were dissected and stored at -20&ordm; C. After complete thawing, samples were subjected to bending test on three points held in universal testing machine mechanics KRATOS&reg;, model KE3000MP, software: TRACOMP-W95. The bones were positioned with its palmar surface (flatter) supported on two tapered bases 5 cm distant from each other, so that the bone gap was positioned at the same distance between the bases. Load was applied on the dorsal surface by a tapered actuator at the midpoint of the bone, where bone defects were set up, with a speed of displacement of 5 mm per minute until the time of bone fracture. During the mechanical test the software generated graphs of force x deformation, where the following biomechanical properties were calculated: maximum strength, rigidity, moment and maximum deformation. Through statistical analysis, there was no difference in the analysis of statistics, maximum strength, rigidity and maximum deformation for both groups. With the results of this research, it can be concluded that the composite did not interfere in biomechanical characteristics of the metacarpal III/IV bone after 180 days of deployment

Nos equinos as fraturas geralmente são de alta energia provocando perda do tecido ósseo. Estas lesões do tecido ósseo ocorrem quando suas propriedades de resistência e rigidez são ultrapassadas. Devido a perda de tecido ósseo diversos métodos são utilizados para corrigir os defeitos ósseos, tanto em ortopedia humana, quanto na medicina veterinária, porém os resultados muitas vezes não são satisfatórios. O desenvolvimento de compostos a base colágeno, quitosana e hidroxiapatita deu-se devido a busca na melhora do comportamento mecânico e biológico dos enxertos. O objetivo deste estudo foi avaliar o comportamento biomecânico do osso III/IV metacarpianos de ovinos após a implantação de compósito de quitosana, hidroxiapatita e colágeno. Foi utilizado seis ovinos fêmeas da raça Santa Inês, os quais foram submetidos à ostectomias unicorticais de cinco milímetros de diâmetro na região média da superfície dorsal do III/IV metacarpianos. Posteriormente, através de sorteio, foi implantado o compósito de quitosana, colágeno e hidroxiapatita em um membro torácico. No membro contralateral foi reproduzida a mesma técnica, porém foi mantido como controle, não sendo preenchido com o compósito. Todos os animais foram submetidos à avaliação física diária. Após 180 dias da criação da falha, os ovinos foram eutanasiados com protocolo autorizado pela Comissão de Ética no Uso de Animais. Os ossos foram dissecados e armazenados á 20&ordm; C. Após o descongelamento completo, as amostras foram submetidas a ensaio de flexão em três pontos realizado em máquina universal de ensaios mecânicos KRATOS&reg;, modelo KE3000MP, software: TRACOMP W95. Os ossos foram posicionados com sua superfície palmar (mais plana) apoiada sobre duas bases cônicas distantes 5 cm entre sí, de modo que a falha óssea ficasse posicionada à mesma distância entre as bases. A carga foi aplicada na superfície dorsal por um atuador cônico no ponto médio do osso, onde foram criadas as falhas ósseas, com velocidade de deslocamento de 5 milímetros por minuto até o momento da fratura do osso. Durante o ensaio mecânico o software gerou gráficos de força x deformação, de onde foram calculadas as seguintes propriedades biomecânicas: força máxima, rigidez, momento e deformação máxima. Através da análise estatística não houve diferença estatísticas na análise da rigidez, força máxima, momento e deformação máxima para ambos os grupos. Com estes resultados podemos concluir que o compósito de quitosana, hidroxiapatita e colágeno não interferiu na consolidação óssea de III/IV metacarpianos de ovinos após 180 dias da implantação. / In equines, the fractures are usually of high energy causing loss of bone tissue. These bone tissue injuries occur when its properties of strength and rigidity are outdated. Due to bone loss, various methods are used to correct the bone defects, both in human and in orthopedic veterinary medicine, but the results often are not satisfactory. The development of chitosan, collagen and hydroxyapatite composite came about due to search the improvement of the mechanical behaviour and biological grafts. The objective of this study was to evaluate the biomechanical behavior of the III/IV metacarpal bone of sheep after the implantation of chitosan, collagen and hydroxyapatite composite. Six healthy female sheep Santa Inês breed were submitted to bilateral unicortical ostectomy (five mm/diameter) on the dorsal aspect of the III/IV metacarpal bone. One front limb was randomly selected for composite implatation. At the contralateral limb was reproduced the same technique, but was kept as control, and are not filled with composite. The animals were submitted to daily physical examination during 180-day follow-up period. After 180 days of failure creation, the animals were euthanized with protocol approved by the Animal Ethics Committee. The bones were dissected and stored at -20&ordm; C. After complete thawing, samples were subjected to bending test on three points held in universal testing machine mechanics KRATOS&reg;, model KE3000MP, software: TRACOMP-W95. The bones were positioned with its palmar surface (flatter) supported on two tapered bases 5 cm distant from each other, so that the bone gap was positioned at the same distance between the bases. Load was applied on the dorsal surface by a tapered actuator at the midpoint of the bone, where bone defects were set up, with a speed of displacement of 5 mm per minute until the time of bone fracture. During the mechanical test the software generated graphs of force x deformation, where the following biomechanical properties were calculated: maximum strength, rigidity, moment and maximum deformation. Through statistical analysis, there was no difference in the analysis of statistics, maximum strength, rigidity and maximum deformation for both groups. With the results of this research, it can be concluded that the composite did not interfere in biomechanical characteristics of the metacarpal III/IV bone after 180 days of deployment

Made available in DSpace on 2014-06-11T19:23:42Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-02-24Bitstream added on 2014-06-13T20:48:19Z : No. of bitstreams: 1 burger_cp_me_jabo.pdf: 769968 bytes, checksum: 7766d90823dbf5c423709325e1af199c (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / O tratamento de não união e união retardada é um desafio constante na rotina do ortopedista veterinário. A dificuldade de se conseguir repouso adequado dos pacientes submetidos à osteossíntese, frequentemente, resulta em consolidações mal sucedidas. Com o objetivo de se avaliar o comportamento do cimento de aluminato de cálcio, foram induzidos defeitos ósseos de 3,57mm de diâmetro nos fêmures de 12 coelhos, sendo os do lado direito preenchidos com o referido biomaterial e os do esquerdo permaneceram vazios. Aos 15, 30 e 60 dias de pós-operatório, realizaram-se avaliações clínico-cirúrgicas, radiográficas e histológicas, a fim de se observar o potencial osteoindutor e osteocondutor do biomaterial no defeito ósseo, e se houve osteointegração. Os resultados evidenciaram que o cimento aluminoso, nesta formulação, não possui esses potenciais e nem poder de osteointegração, possivelmente por possuir porosidade reduzida / The treatment of non union and delayed union is a constant challenge for veterinary orthopedists. The difficulty in achieving adequate rest for patients which have undergone osteosynthesis results in unsuccessful bone consolidations. With the aim of evaluating the behavior of a calcium aluminate cement, bone defects of 3,57 mm of diameter were induced in femurs of 12 rabbits. The defects on the right side were filled with the biomaterial and the ones on the left side remained unfilled. The evaluation periods occurred at 15, 30 and 60 days after surgery. Clinical, surgical, radiographic and histological evaluations were performed in order to observe the osteoinductive and osteocondoctive potential of the biomaterial on the bone defects, as well to verify if there was osteointegration. The results showed that the aluminate cement does not have these potencial and nor cause osteointegration in the formulation used in this study

Made available in DSpace on 2014-06-11T19:23:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2005Bitstream added on 2014-06-13T19:50:51Z : No. of bitstreams: 1 pereirajunior_ocm_me_botfmvz.pdf: 3167867 bytes, checksum: 1d9dcf46127172271d23518809985b22 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Objetivou-se avaliar, por meio de exames radiográficos e histológicos, a função da resina de poliuretana derivada do óleo de mamona (Ricinus communis), na forma de grânulos, no tratamento de defeito ósseo segmentar induzido no rádio de coelhos, tendo como padrão comparativo o enxerto ósseo esponjoso autólogo. Foram utilizados 20 coelhos da raça Norfolk, fêmeas, com idade entre 12 e 14 meses e peso entre 4 e 5kg. Uma falha óssea segmentar de 1,0 cm de comprimento foi induzida na diáfise de ambos os rádios pela excisão de fragmento osteoperiosteal. No rádio esquerdo o defeito foi tratado com a resina de poliuretana e no direito com auto-enxerto esponjoso colhido do úmero proximal esquerdo. Para realização dos exames histológicos foram eutanaziados cinco animais aos 15 dias, 30 dias, 60 dias e 120 dias de pós-operatório. A regeneração óssea foi maior no defeito tratado com auto-enxerto esponjoso em todos os períodos de observação, sendo que, aos 120 dias de pós-operatório, estes estavam totalmente reconstituídos. Pela avaliação histológica o polímero de mamona atuou como preenchedor de espaço, minimizando a produção de tecido fibroso no local, além de não apresentar sinais de reabsorção em nenhum dos momentos de avaliação. Foi possível concluir que o polímero de mamona na forma de grânulos é biocompatível e osteointegrável, porém não apresenta a mesma capacidade de regeneração óssea do auto-enxerto esponjoso. / The aim of the present study was to compare, by radiographic and histological analyses, the castor oil plant polyurethane in granules presentation, applied to a segmental bone defect, created in both radial diaphyses, to the cancellous bone autograft, in order to evaluate an alternative to bone defect healing. Norfolk adult female rabbits, with approximately 13 months of age and a mean body weight of 4.5kg were used. Thus, a one-cm segmental defect was created in both radial diaphyses. The defect in the left radius was filled with the castor oil plant polyurethane, and the right one, filled with cancellous bone autograft, collected from the left proximal humerus. The rabbits were euthanased at 15, 30, 60 and 120 days post-surgery (5 animals/period), in order to proceed the histological analysis. New bone formation was increased and accelerated in the defect treated with cancellous bone autograft along all periods of observation. In the last moment (120 days), the defects were totally reconstituted and remodeled. The polyurethane acted as a space filler, minimizing the local production of fibrous tissue. No granules degradation or reabsorb were detected, as well as any inflammatory reaction. Thus, it was possible to conclude that the castor oil plant polyurethane, in granules presentation, was biocompatible and osteointegrated, but did not show the same bone regeneration capacity of the cancellous bone autograft.

Resumo: O tratamento de não união e união retardada é um desafio constante na rotina do ortopedista veterinário. A dificuldade de se conseguir repouso adequado dos pacientes submetidos à osteossíntese, frequentemente, resulta em consolidações mal sucedidas. Com o objetivo de se avaliar o comportamento do cimento de aluminato de cálcio, foram induzidos defeitos ósseos de 3,57mm de diâmetro nos fêmures de 12 coelhos, sendo os do lado direito preenchidos com o referido biomaterial e os do esquerdo permaneceram vazios. Aos 15, 30 e 60 dias de pós-operatório, realizaram-se avaliações clínico-cirúrgicas, radiográficas e histológicas, a fim de se observar o potencial osteoindutor e osteocondutor do biomaterial no defeito ósseo, e se houve osteointegração. Os resultados evidenciaram que o cimento aluminoso, nesta formulação, não possui esses potenciais e nem poder de osteointegração, possivelmente por possuir porosidade reduzida / Abstract: The treatment of non union and delayed union is a constant challenge for veterinary orthopedists. The difficulty in achieving adequate rest for patients which have undergone osteosynthesis results in unsuccessful bone consolidations. With the aim of evaluating the behavior of a calcium aluminate cement, bone defects of 3,57 mm of diameter were induced in femurs of 12 rabbits. The defects on the right side were filled with the biomaterial and the ones on the left side remained unfilled. The evaluation periods occurred at 15, 30 and 60 days after surgery. Clinical, surgical, radiographic and histological evaluations were performed in order to observe the osteoinductive and osteocondoctive potential of the biomaterial on the bone defects, as well to verify if there was osteointegration. The results showed that the aluminate cement does not have these potencial and nor cause osteointegration in the formulation used in this study / Orientador: Cíntia Lucia Maniscalco / Coorientadora: Paola Castro Moraes / Banca: Julio Carlos Canola / Banca: Gustavo Garkalns de Souza Oliveira / Mestre