Submitted by Cláudia Bueno (claudiamoura18@gmail.com) on 2016-01-06T16:16:41Z No. of bitstreams: 2 Dissertação - Ygor Roberto de Carvalho - 2009.pdf: 1167127 bytes, checksum: 7fe8cf1100e0875c875d048be01ffbbc (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-01-07T08:16:45Z (GMT) No. of bitstreams: 2 Dissertação - Ygor Roberto de Carvalho - 2009.pdf: 1167127 bytes, checksum: 7fe8cf1100e0875c875d048be01ffbbc (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2016-01-07T08:16:45Z (GMT). No. of bitstreams: 2 Dissertação - Ygor Roberto de Carvalho - 2009.pdf: 1167127 bytes, checksum: 7fe8cf1100e0875c875d048be01ffbbc (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2009-09-28 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Peritoneal adhesions are fibrous bands that form abnormal unions between two or more serosal coating surfaces, may cause obstructions of abdominal tubular organs and pelvic pain. Several studies have been performed using antiinflammatory, anticoagulant, proteolytic agents and biomaterials in the form of film or gel, with the aim of preventing or simply reduce the formation of peritoneal adhesions. The chitosan is a polymer obtained by deacetylation of chitin, a polysaccharide obtained from the exoskeleton of crustaceans and has been used in various medical specialties as a biomaterial. The aim of this study was to evaluate the film based on chitosan as a barrier in the formation of postoperative intestinal adhesions in rabbits. For this, 30 rabbits used were male adult, race New Zealand, with an average weight of three kilograms and clinically healthy, of which 15 were submitted to enterotomy (control group) and 15 to enterotomy with overlap of the chitosan-based film at the intestinal incision (treatment group). Five animals from each group were assessed at seven, 14 and 21 days postoperatively, when held to the macroscopic evaluation of adhesions with regard presence, extent and type, and also performed microscopic evaluation of the enterorrhaphy site and hematimetric exams. The adhesions occurred in 80% of subjects in the control group and 86.7% of treatment group. In the control group 50% of the animals developed adhesions between the site of enterorrhaphy and abdominal wall, while in the treatment group 76.9% of individuals had adhesions between the site of enterorrhaphy and adjacent bowel. The control group had formed adhesions extensions higher than in treatment group. We found statistical differences between subgroups T7 and C7, C14 and T14 on the extent of adhesions (p ≤ 0.05) but not between C21 and T21. Also no significant differences between subgroups on the type of adhesions were seen. As for the histopathological evaluation, there was significant difference (p ≤ 0.05) between the subgroup C7, where 80% of samples the score was considered strong, and T7 in that 80% of the samples was considered moderate score on the concentration of fibroblasts and angiogenesis. Regarding the variable necrosis, was observed in 40% of samples of T7 and 0% of C7 and therefore statistically different (p ≤ 0.05). Significant differences (p ≤ 0.05) were also found between the groups C14 and T14 on variables heterophils (C14, 80% score discreet, T14, 80% score marked), eosinophils (score of 60% in discrete T14, but absent in C14) and necrosis (mild in 60% of C14 and severe in 80% of T14). In subgroups C21 and T21 only the scores of mononuclear cells were statistically different (p ≤ 0.05). The hematimetric variables remained within the normal values for the species. Based on the results we can conclude that the chitosan-based film reduces the extent of intestinal adhesions in rabbits and is useful as a barrier system in this species and that this film, when overlaid with a wound of rabbits induces intestinal tissue response to formation of caseous material. / Aderências abdominais ou peritoniais são faixas fibrosas que formam uniões anormais entre duas ou mais superfícies serosas de revestimento, podendo causar obstruções de órgãos abdominais tubulares e dores pélvicas. Diversos estudos já foram realizados utilizando antiinflamatórios, anticoagulantes, agentes proteolíticos e ainda biomateriais na forma de filme ou gel, com a finalidade de prevenir ou simplesmente reduzir a formação de aderências peritoniais. A quitosana é um polímero obtido pela desacetilação da quitina, que é um polissacarídeo oriundo do exoesqueleto de crustáceos e vem sendo utilizado em diversas especialidades médicas como biomaterial. O objetivo deste estudo foi avaliar o filme à base quitosana como barreira na formação de aderências intestinais pós-operatórias em coelhos. Para isso, utilizou-se 30 leporinos machos, adultos, da raça Nova Zelândia, com peso médio de três quilos e clinicamente sadios, dos quais 15 foram submetidos à enterotomia (grupo controle) e 15 à enterotomia e sobreposição do filme à base de quitosana sobre a incisão cirúrgica intestinal (grupo tratamento). Cinco animais de cada grupo foram avaliados aos sete, 14 e 21 dias pós-operatórios, quando se realizou a avaliação macroscópica das aderências quanto à presença, extensão e o tipo, sendo também realizada avaliação microscópica do sítio da enterorrafia e hematimetria. As aderências ocorreram em 80% dos indivíduos do grupo controle e 86,7% do grupo tratamento. No grupo controle em 50% dos animais as aderências formaram-se entre o sítio da enterorrafia e parede abdominal, enquanto no grupo tratamento 76,9% dos indivíduos apresentaram aderências entre o sítio da enterorrafia e alças intestinais adjacentes. No grupo controle as aderências formadas possuíam extensões maiores que no grupo tratamento. Foram encontradas diferenças estatísticas entre os subgrupos C7 e T7; C14 e T14 quanto à extensão das aderências (p≤ 0,05), mas não entre C21 e T21. Também não foram observadas diferenças significativas entre os subgrupos quanto ao tipo de aderências. Quanto à avaliação histopatológica, houve diferença significativa (p≤ 0,05) entre o subgrupo C7, em que 80% das amostras o escore foi considerado acentuado, e T7 em que 80% das amostras o escore foi considerado moderado quanto à concentração de fibroblastos e angiogênese. Em relação à variável necrose, esta foi observada em 40% das amostras de T7 e 0% de C7 sendo, portanto estatisticamente diferente (p≤ 0,05). Diferenças significativas (p≤ 0,05) também foram encontradas entre os subgrupos C14 e T14 quanto às variáveis heterófilos (C14, 80% escore discreto; T14, 80% escore acentuado), eosinófilos (escore discreto em 60% de T14, porém ausentes em C14) e necrose (discreta em 60% de C14 e acentuada em 80% de T14). Já nos subgrupos C21 e T21 apenas os escores das células mononucleares foram estatisticamente diferentes (p≤ 0,05). As variáveis hematimétricas permaneceram dentro dos valores considerados normais para a espécie. Com base nos resultados pode-se concluir que o filme à base de quitosana reduz a extensão das aderências intestinais em coelhos, sendo útil como sistema de barreira nessa espécie e que este filme, quando sobreposto a uma ferida intestinal de coelhos induz a resposta tissular com formação de material caseoso.

Aiming at to develop a model of experimental induction of patent ductus arterious by thoracotomy, to study a corrective technique for the experimental defect by video-assisted thoracic surgery (VATS) and to evaluate eventual adhesions by thoracoscopy, three experiments were done. For each experiment were used 14 adult mongrel dogs, weighting 10 to 20 kg. In the PDA induction experiment it was possible to implant the autologous graft in the same anatomical localization of the congenital PDA, the left subclavy artery can be used as a patent graft simulating PDA, and this model did not cause cardiac injuries (detectable by visualization and CK and CKMB dosages). In conclusion, this model can be used as a base for new researches for the treatment of PDA, for the training of surgical correction technics and for other studies in veterinary medicine cardiology. In the proposed correction technique, three work ports and the optics were enough and adequately located for the correction of the PDA; surgical materials for vascular surgery can be used for the accomplishment of this technique; the positioning of the surgical team, the patient, the equipments and the instruments were adequated; the knot of Roeder was effective; this correction technique was viable up to five days after the induction of the PDA. In conclusion, this technique is effective and can be used on clinical cases for the occlusion of the congenital PDA and in the training of video-endoscopic surgeons. In the adhesions evaluation study, it was observed that thoracotomy and VATS induced the adhesions formation; these adhesions were located along VATS and thoracotomy incisions, and their extension was smaller after VATS, due to smaller tissue damage extension; it was possible to lise the adhesions by thoracoscopy in up to five days of postoperative, being necessary two work ports; the increase of the CK seric levels was proportional to the tissue damage. In conclusion, thoracotomy and VATS induce the formation of adhesions. High incidence of adhesions post thoracotomy and post VATS may lead to serious surgical risks and requires special care in future surgical reinterventions. This scintific work was approved by the animal welfare committee (012/2005) of the Universidade Federal de Santa Maria and all the animals used in this work were adopted. / Objetivando-se desenvolver um modelo de indução experimental de ducto arterioso patente por toracotomia, estudar uma técnica corretiva do defeito experimental por cirurgia torácica vídeo-assistida (CTVA) e avaliar eventuais aderências por toracoscopia, realizaramse três experimentos. Foram utilizados, para cada experimento, 14 cães adultos sem raça definida, cujos pesos variaram de 10 a 20 kg. Quanto ao modelo de indução de DAP, foi possível implantar-se enxerto autólogo na mesma localização anatômica do DAP congênito, a artéria subclávia esquerda pode ser utilizada para enxerto autólogo simulando DAP, apresentando patência, e não houve lesões cardíacas resultantes do modelo experimental proposto (passíveis de detecção por visualização e por dosagem de CK e CKMB). Concluiuse que o modelo, experimentalmente induzido, de D.A.P. com enxerto autólogo da artéria subclávia esquerda é viável. O presente modelo pode servir de base para novas pesquisas no tratamento de DAP, no treinamento em técnicas de correção cirúrgica e, ainda, em outros estudos da cardiologia veterinária. Na técnica proposta para correção do defeito experimental, os três portais de trabalho e a ótica foram suficientes e se localizaram adequadamente para a correção do DAP; materiais de cirurgia vascular podem ser empregados para a realização desta técnica; o posicionamento da equipe cirúrgica, do paciente, dos equipamentos e dos instrumentais foi adequado; o nó de Roeder mostrou-se efetivo; o procedimento proposto é viável no período de até cinco dias de pós-operatório. Concluiu-se que a técnica de correção de DAP congênito por CTVA se mostrou efetiva, podendo ser empregada na rotina clínica, e, também para treinamento de cirurgiões vídeo-endoscópicos. No estudo das aderências, as cirurgias de toracotomia e de CTVA predispõem a formação de aderências, que abrangem os locais de incisão de toracotomia e de CTVA. Sua extensão é menor após CTVA, devido à menor extensão do dano tecidual. É possível desfazerem-se as aderências por toracoscopia, em até cinco dias de pós-operatório, sendo necessários dois portais. O aumento dos níveis séricos de CK é proporcional ao trauma tecidual. Nas condições em que este trabalho foi realizado, concluiu-se que as cirurgias de toracotomia e de CTVA (cirurgia torácica vídeo assistida) levam a formação de aderências. A alta incidência de aderências póstoracotomia e pós-CTVA predispõe a sérios riscos cirúrgicos e requer cuidados especiais em futuras reintervenções cirúrgicas. Este trabalho foi aprovado pela comissão de ética da UFSM sob número 012/2006. Todos os animais foram encaminhados para adoção.

A number of studies have demonstrated the pivotal role of collagen in modulating cell growth and differentiation. In bone, where the extracellular matrix is composed of approximately 85% type I collagen, cellular interaction with matrix components has been shown to be important in the regulation of the osteoblast phenotype. Preservation or enhancement of normal osteoblast function and appositional bone formation after implant placement represents a strategy that can be useful for the purpose of improving osseointegration. In order to further improve biocompatibility, we combined two known favorable compounds, namely the titanium alloy, Ti6A14V, with type I collagen. We assessed the in vitro behavior of primary osteoblasts grown on both fibrillar collagen-coated and tropocollagen-coated Ti6A14V in comparison with uncoated titanium alloy, using an improved adsorption procedure. As parameters of biocompatibility, a variety of processes, including cell attachment, spreading, cytoskeletal organization, focal contact formation, proliferation and expression of a differentiated phenotype, were investigated. Our results demonstrated for the first time that in comparison to uncoated titanium alloy, collagen-coated alloy enhanced spreading and resulted in a more rapid formation of focal adhesions and their associated stress fibers. Growing on collagen-coated Ti6A14V, osteoblasts had a higher proliferative capacity and the intracellular expression of osteopontin was upregulated compared to uncoated titanium alloy. Type I collagen-coated titanium alloy exhibits favorable effects on the initial adhesion and growth activities of osteoblasts, which is encouraging for its potential use as bone graft material. Moreover, collagen type I may serve as an excellent biocompatible carrier for osteotropic factors such as cell adhesion molecules (e.g. fibronectin) or bone-specific growth factors. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Astrocytes are emerging as important regulators of neural circuit function and behavior in the healthy and diseased nervous system. In a screen for astrocyte molecules that modulate neuronal hyperexcitability we identified multiple components of focal adhesion complexes (FAs) as potent suppressors of genetically- or pharmacologically-induced seizure-like activity. Depletion of astrocytic Tensin, b-integrin, Talin, Focal adhesion kinase (FAK), or matrix metalloproteinase 1 (Mmp1), which degrades extracellular matrix to activate b-integrin receptors, resulted in enhanced recovery from, or resistance to seizure activity. Reciprocally, promoting FA signaling by overexpression of Mmp1 in astrocytes led to enhanced-seizure severity. Blockade of FA signaling in astrocytes led to reduced-astrocytic coverage of the synaptic neuropil and reduced expression of the excitatory amino acid transporter EAAT1. However, upon seizure induction, depletion of FA signaling components resulted in enhanced astrocyte coverage of the synaptic neuropil and a ~2-fold increase in EAAT1 levels compared to controls. Our data indicate that FAs promote astrocyte coverage in neuropil and EAAT1 expression under normal physiological conditions, but in the context of hyperexcitability, FAs negatively regulate the extent of astrocytic processes within neuropil and EAAT1 expression, thereby inhibiting a more rapid recovery from conditions of excessive neuronal activity.

Le titane (Ti) est largement utilisé en orthopédie et médecine dentaire. Ce matériau présente d´excellentes propriétés mécaniques, est biocompatible et résiste à la corrosion. L’interaction entre les cellules et la surface d’un implant joue un rôle décisif dans l’ostéointégration. Malgré la grande variété d’études que nous trouvons dans la littérature, le comportement des cellules en contact avec des matériaux implantables comme le Ti n’est toujours pas élucidé à toutes les échelles topographiques. Notre laboratoire a développé une méthode de modification physico-chimique de la surface de métaux à intérêt médical. Cette méthode génère des surfaces nanoporeuses qui favorisent la différenciation de cellules souches, affectent le comportement cellulaire de façon différentielle, promeuvent la formation osseuse in vitro et in vivo, et qui ont une capacité antibactérienne. Afin de mieux comprendre comment cette surface influence le comportement cellulaire, nous avons étudié leur influence sur la formation et la maturation des adhésions focales (FAs, de l’anglais) et la formation des filopodes. De plus, nous avons examiné comment les caractéristiques physico-chimiques de la surface obtenue guident l’expression génique des protéines associées aux FAs et aux filopodes en utilisant différentes lignées cellulaires. Finalement, afin de mieux comprendre la biomécanique de la cellule, la force d’adhésion à la surface des filopodes a été déterminée à l’aide de la microscopie à force atomique (AFM). Des disques de Ti commercialement pur (Cp-Ti) ont été polis a fini miroir (Ti-Control), une partie des disques a été traité avec un mélange d’acide sulfurique et de peroxyde d’hydrogène pour créer une surface nanostructurée poreuse (Ti-Nano). L’influence de la nanoporosité, de la cristallinité et la mouillabilité de cette surface sur des cellules pre-ostéoblastiques de souris (MC3T3) et des bactéries a été évalué par la microscopie électronique à balayage (MEB) et par immunofluorescence (IF). Nous avons ensuite utilisé une lignée cellulaire épithéliale (CHO-K1) qui exprime la paxilline (une protéine des FAs) de type sauvage ou la paxilline avec des mutations. De plus, la force d’interaction des filopodes avec la surface a été quantifié en mesurant la force latérale nécessaire pour les déplacer avec une pointe d’AFM. Finalement, la centrifugation a été utilisée pour étudier les changements fonctionnels des cellules MC3T3. L’analyse du comportement des cellules MC3T3 sur des surfaces amorphes et cristallines n'a pas montré de différence par rapport au nombre des cellules ou la quantité des FAs. La cristallinité de la couche superficielle n’avait également aucune incidence sur l’adhésion bactérienne. Les deux lignées cellulaires utilisées ont montré une présence abondante de filopodes avec des nanoprotrusions latérales en réponse à la nanoporosité. La taille et la forme des cellules CHO-K1 ont été grandement affectées par la topographie. L’expression génique des protéines associées aux différents marqueurs des FAs et aux protrusions a été aussi significativement augmentée sur la surface nanoporeuse, quel que soit le type de cellule. Les filopodes sur Ti-Nano ont montré une plus grande résistance au détachement latéral, ce qui indique qu'ils adhèrent à la surface avec plus de force. Également, l’analyse par MEB a révélé une restructuration de la membrane cellulaire accompagnée d’un changement de la forme cellulaire après centrifugation. Parce que les mitochondries fournissent de l’énergie pour les processus cellulaires, l’organisation du réseau mitochondrial a été influencée aussi par la topographie de surface et la centrifugation. Bien qu’il ne puisse pas être exclu que la cristallinité et la mouillabilité de la surface contribuent dans une certaine mesure à déterminer le comportement des cellules, nos résultats suggèrent que les caractéristiques physiques des surfaces représentent le principal déterminant. Nous avons démontré aussi, pour la première fois, que la topographie de surface peut modifier l’interaction adhésive d’une structure subcellulaire qui est fondamentale dans la détection des caractéristiques physico-chimiques des surfaces. En conclusion, nos résultats montrent que la topographie de surface peut modifier des propriétés fondamentales dans les cellules. Dans leur ensemble, ils soulèvent la possibilité que les surfaces nanostructurées puissent être utilisées non seulement pour guider/accélérer l’intégration de biomatériaux dans des conditions normales, mais également dans des situations où l’activité cellulaire est compromise ou également pour les prothèses soumises à des charges externes, telles que les implants orthopédiques et dentaires. / Titanium (Ti) is widely used in orthopedics and dentistry. This material has excellent mechanical properties, is biocompatible and corrosion resistant. The interaction between the cells and the surface of an implant plays a key role in osseointegration. Despite the wide variety of studies found in the literature, the behavior of cells in contact with implantable materials such as Ti is not yet fully elucidated at all topographic scales. Our laboratory has developed a method for the physicochemical modification of the surface of medically relevant metals. This method generates nanoporous surfaces that promote stem cell differentiation, differentially affect cellular behavior, promote bone formation in vitro and in vivo and have antibacterial capacity. To better understand how this surface influences cell behavior, we studied their influence on the formation and maturation of focal adhesions (FAs) and filopodia formation. Furthermore, we examined how the physicochemical characteristics of the resulting surface guide the gene expression of proteins associated with FAs and filopodia using different cell lines. Finally, to better understand the biomechanics of the cell, the adhesion strength of filopodia to the surface was determined using atomic force microscopy (AFM). Commercially pure Ti discs (Cp-Ti) were polished to a mirror finish (Ti-Control), some of the polished discs were treated with a mixture of sulfuric acid and hydrogen peroxide to create a nanostructured surface (Ti-Nano). The influence of nanoporosity, crystallinity and wettability of this surface on mouse pre-osteoblastic cells (MC3T3) and bacteria was evaluated by scanning electron microscopy (SEM) and immunofluorescence. Then, to evaluate the response to nanotopography, we used an epithelial cell line (CHO-K1) that expresses wild type paxillin (a protein of FAs) or paxillin with mutations. In addition, the interaction forces of the filopodia with the surface were quantified by measuring the lateral force required to displace these structures from the surface with an AFM tip. Finally, centrifugation was used to study functional changes in MC3T3 cells. Analysis of the behavior of MC3T3 cells on amorphous and crystalline surfaces showed no difference in cell number or the number of focal adhesions. The crystallinity of the surface layers also had no effect on bacterial adhesion. Both cell lines used showed abundant presence of filopodia 4 with lateral nanoprotrusions in response to nanoporosity. The size and shape of CHO-K1 cells was greatly affected by the topography. Gene expression of proteins associated with different focal adhesion markers and protrusions was also significantly increased on the nanoporous surface, regardless of cell type. Filopodia on the Ti-Nano showed greater resistance to lateral detachment force, indicating that they adhere to the surface with greater strength. Also, SEM analysis revealed a restructuring of the cell membrane accompanied by a corresponding change in cell shape after centrifugation. Because mitochondria provide energy for cell processes, the organization of the mitochondrial network was also influenced by surface topography and centrifugation. Although it cannot be excluded that surface crystallinity and wettability contribute to some extent to determining cell behavior, our results suggest that the physical characteristics of the surfaces represent the main determinant. We have also shown for the first time that surface topography can modify the adhesive interaction of a subcellular structure that is fundamental in the detection of the physicochemical characteristics of surfaces. In conclusion, our results show that surface topography can modify fundamental properties in cells. Together, they raise the possibility that nanostructured surfaces can be used not only to guide/accelerate the integration of biomaterials under normal conditions, but also in situations where cellular activity is compromised or also for prostheses under external loads, such as orthopedic and dental implants.

No description available.

No description available.

Peritoneale Verwachsungen sind die häufigste Komplikation nach operativen Eingriffen. Sie haben abdominelle Beschwerden, chronische Ileuszustände und den akuten Ileus zur Folge. Diese peritonealen Reaktionen sind bei Neugeborenen und Säuglingen besonders ausgeprägt. Seit es operative abdominelle Eingriffe gibt, stellt das Vermeiden von peritonealen Adhäsionen ein zentrales Problem dar. Eine Vielzahl von Substanzen, lokal oder systemisch angewendet, wurde getestet, um Adhäsionen zu vermeiden. Bis heute hat sich kein gesicherter Standard für die Sekundärprophylaxe von Adhäsionen etabliert. Eine nicht ausreichende Wirksamkeit oder klinisch nicht akzeptable Nebenwirkungen sind dafür die Ursache. Das primäre Vermeiden von Verwachsungen steht nach wie vor im Mittelpunkt chirurgischer Bemühungen. Das organschonende Operieren und das Verbannen von Talkum an den Handschuhen der Chirurgen sind weltweit anerkannte Maßnahmen der Primärprophylaxe von Adhäsionen. Dass man auch den Abrieb von Bauchtüchern, die üblicherweise aus Baumwolle gefertigt sind, für die Entstehung von Adhäsionen verantwortlich machen muss, ist seit langem bekannt, wurde aber bisher in der operativen Praxis weitestgehend ignoriert. Die vorliegende tierexperimentelle Arbeit am Rattenmodell zeigt, dass die Verwendung alternativer Werkstoffe (Polyestergewebe) anstelle der üblichen Baumwolltücher zu einer deutlichen Verminderung der Adhäsionszahl und -stärke führt. Im zweiten Teil der Arbeit wird gezeigt, dass neben diesen primärprophylaktischen Maßnahmen auch sekundär Adhäsionen reduziert werden können. Wir untersuchten hierzu die Wirkung von PF 5080, einem Perfluorcarbon, auf das Peritoneum. Eine deutliche Reduktion der postoperativen Verwachsungen am Rattenmodell ließ sich nachweisen. Die lokale und systemische Wirkungsweise dieser Substanz ist noch weitgehend unbekannt und bedarf weiterer Forschung. / Peritoneal adhesions are the most common complication after surgical procedures. They often cause abdominal pain and bowel obstruction. Those peritoneal reactions are very intense in newborn and infants. Since the first days of open abdominal surgery the avoidance of adhesions has been a key problem. A countless array of drugs for local or systemic use to reduce adhesions has been tested. Until now no proven standard of secondary prophylaxis against adhesions has been established. The reasons are inefficiency or unacceptable side effects. The primary avoidance of adhesions is still the main focus for surgeons. Surgical techniques which keeps the organ carefully and the banishment of talcum from surgical gloves are widely acknowledged standards in the primary prophylaxis of adhesions. The fact that cotton particles from surgical swabs also contribute to postoperative adhesions has been known for along time but until now ignored in surgical practice. This study shows that the use of alternative material like polyester instead of cotton during operation does strongly reduce the formation of adhesions in rat. A further finding of this study is that the instillation of PF 5080, a Perfluorocarbon, in the late phase of the operation in the abdominal cavity does also reduce postoperative adhesions in rat. The local and systemic mode of function remains unknown and will be the subject to further research.

Atualmente os defeitos herniários da parede abdominal são freqüentemente corrigidos com o uso de biomateriais. Embora utilizada com bons resultados há várias décadas, a prótese de Polipropileno (PP) tem implicado graves complicações decorrentes de aderências aos órgãos abdominais. A prótese de Politetrafluoroetileno expandido (PTFEe) tem reconhecidamente menor potencial aderencial; no entanto, dados obtidos de estudos biomecânicos deixam dúvida quanto a sua real eficiência na correção herniária. O objetivo do estudo foi comparar esses dois diferentes tipos de próteses na correção de defeitos ventrais produzidos em ratos Wistar, levando-se em consideração parâmetros histológicos, biomecânicos e da resposta aderencial. Para o estudo histológico um grupo de animais (n=21) foi submetido simultaneamente a implante subperitoneal de fragmentos de próteses de PP e PTFEe. Para o estudo comparativo da resposta biomecânica e aderencial entre as próteses, procedeu-se ao implante protético subperitoneal com PP (n=21) e PTFEe (n=21) para corrigir defeitos ventrais criados cirurgicamente envolvendo toda a espessura da parede abdominal dos animais. Para análise biomecânica, dois outros grupos de animais foram utilizados como controle: um grupo não submetido à cirurgia (n=15) e um grupo com correção de defeitos ventrais por meio de sutura (n=21). Todas as avaliações foram realizadas com 1, 2 e 4 semanas de pós-operatório e constituíram-se de: avaliação da resposta aderencial por meio de pesquisa da área de prótese aderida e incidência de aderência a órgãos, avaliação biomecânica por meio de ensaios de tração de tiras de parede abdominal e avaliação morfométrica do tecido inflamatório e das fibras colagênicas em cortes histológicos corados por Hematoxilina-eosina e pelo método da Picrossírius-polarização, respectivamente. Os resultados mostraram que: a fração de volume de tecido inflamatório no grupo PP na primeira, segunda e quarta semanas foi respectivamente: 20%, 9% e 4% enquanto no grupo PTFEe: 30%, 16% e 16%. Houve diferença estatística na segunda e quarta semanas. A fração de volume de colágeno fibrilar no grupo PP foi respectivamente: 65%, 71% e 77%, na primeira, segunda e quarta semanas. No grupo PTFEe os valores foram: 55%, 66% e 68%, na primeira, segunda e quarta semanas. Da mesma forma, houve diferença estatística na segunda e quarta semanas. Na análise semiquantitativa do grau de agregação de colágeno foi observado diferença estatística apenas primeira semana de pós-operatório a favor do PP (3,24 x 1,40 p=0,022). As próteses induziram valores semelhantes de área aderida na primeira (67,85%-PP x 71,42%- PTFEe), segunda (60,71%-PP x 60,71%-PTFEe) e quarta semanas de pós-operatório (46,42% PP x 42,85% PTFEe). Quanto à presença de aderência a órgãos abdominais houve diferença entre as próteses apenas na primeira semana a favor do PTFEe: enquanto 85,7% dos animais no grupo PP apresentaram aderências à órgãos, esse índice foi de apenas 28,5% no grupo PTFEe. Os valores de força máxima obtidos nos ensaios biomecânicos de tração com a prótese de PP foram na primeira, segunda e quarta semanas: 20,54 N, 21,62 N e 26,23 N. No grupo PTFEe os valores na primeira, segunda e quarta semanas foram: 16,92 N, 23,12 N e 25,41 N. Foi observada diferença estatística na primeira semana de pós-operatório. A comparação entre os implantes protéticos de PP e PTFEe nas condições da presente pesquisa permitiu concluir: 1) A estimativa de área aderida à prótese foi semelhante independentemente do material implantado; 2) Com 1 semana de pós-operatório, o implante de PP demonstrou-se mais resistente aos ensaios biomecânicos de tração o que se correlacionou a um maior grau de agregação das fibras colagênicas nos tecidos implantados; 3) Com 1 semana de pós-operatório, os implantes de PTFEe induziram aderências as órgãos abdominais em um menor número de animais; 4) Com 2 e 4 semanas de pós-operatório o implante de PP induziu a uma menor infiltração de tecido inflamatório e a um maior depósito de colágeno fibrilar / Nowadays, abdominal wall defects are frequently repaired with biomaterials. Although utilized with good results for several decades, polypropylene mesh (PP) has been implicated with serious complications due to adhesion to the abdominal organs. It has been reported that prostheses of expanded polytetrafluoroethylene (ePTFE) mesh exhibit less adhesion formation potential; however, data obtained by biomechanical studies leave doubt as to its real efficiency in hernia repair. The objective of the present study was to compare these two types of mesh in the correction of ventral defects created in Wistar rats, taking into account histological and biomechanical parameters and the adhesion response. For the histological study, a group of animals (n = 21) was submitted simultaneously to subperitoneal implantation of fragments of PP and ePTFE mesh. For the comparative study of the biomechanical and adhesion response between the prostheses, subperitoneal implantation with PP (n = 21) and ePTFE mesh (n = 21) was performed to repair surgically created abdominal defects, involving all layers of the abdominal wall. In the biomechanical analysis, two other groups of animals were used for the control: a group not submitted to surgery (n = 15) and a group with abdominal wall defects repaired with sutures (n = 21). At postoperative weeks 1, 2 and 4, the following evaluations were performed: study of the adhesion response by measuring the incidence of adherence to organs and area of adhered prosthesis; biomechanical test of abdominal wall strips; and morphometric study of the inflammatory tissue and collagenic fibers in sections stained with hematoxylin-eosin and by Picrosiriuspolarization technique. The results showed that: the inflammatory tissue volume in group PP at postoperative weeks 1, 2 and 4, respectively, was 20%, 9% and 4%; while in the group ePTFE the values were 30%, 16% and 16%. The difference was statistically significant in postoperative weeks 1 and 4. The collagen fibril volume in group PP was: 65%, 71% and 77%, in postoperative weeks 1, 2 and 4, respectively. In group ePTFE the values were: 55%, 66% and 68%. Likewise, there was a statistically significant difference in postoperative weeks 2 and 4. In the semi-quantitative analysis of the degree of collagen aggregation, a statistically significant difference was only observed in postoperative week 1, in favor of PP (3.24 x 1.40, p = 0.022). The prostheses induced similar values for adhered area in postoperative week 1 (67.85%-PP vs. 71.42%-ePTFE), week 2 (60.71%-PP vs. 60.71%-ePTFE) and week four (46.42% PP vs. 42.85% ePTFE). Regarding the presence of adherence to abdominal organs, there was only a statistically significant difference between the prostheses in week one, in favor of ePTFE. While 85.7% of the animals in group PP presented adherence to organs, this index was only 28.5% in group ePTFE. The maximum force obtained in the biomechanical tests with the PP mesh was 20.54 N, 21.62 N and 26.23 N, in postoperative weeks 1, 2 and 4, respectively. In group ePTFE the values were 16.92 N, 23.12 N and 25.41 N. A statistically significant difference was observed in postoperative week 1. The comparison between PP and ePTFE prosthetic implants in the conditions of the present research enabled the conclusion that: 1) the estimated area adhered to the prostheses was similar, irrespective of the implanted material; 2) at postoperative week 1, the resistance to traction was higher when the repair was done with PP mesh, which was correlated to a higher degree of collagen fiber aggregation in the implanted tissues; 3) at postoperative week 1, fewer visceral adhesions were formed on ePTFE group of animals; and 4) at postoperative weeks 2 and 4, the PP implant induced a smaller infiltration of inflammatory tissue and a larger deposit of collagen fibrils

Atualmente os defeitos herniários da parede abdominal são freqüentemente corrigidos com o uso de biomateriais. Embora utilizada com bons resultados há várias décadas, a prótese de Polipropileno (PP) tem implicado graves complicações decorrentes de aderências aos órgãos abdominais. A prótese de Politetrafluoroetileno expandido (PTFEe) tem reconhecidamente menor potencial aderencial; no entanto, dados obtidos de estudos biomecânicos deixam dúvida quanto a sua real eficiência na correção herniária. O objetivo do estudo foi comparar esses dois diferentes tipos de próteses na correção de defeitos ventrais produzidos em ratos Wistar, levando-se em consideração parâmetros histológicos, biomecânicos e da resposta aderencial. Para o estudo histológico um grupo de animais (n=21) foi submetido simultaneamente a implante subperitoneal de fragmentos de próteses de PP e PTFEe. Para o estudo comparativo da resposta biomecânica e aderencial entre as próteses, procedeu-se ao implante protético subperitoneal com PP (n=21) e PTFEe (n=21) para corrigir defeitos ventrais criados cirurgicamente envolvendo toda a espessura da parede abdominal dos animais. Para análise biomecânica, dois outros grupos de animais foram utilizados como controle: um grupo não submetido à cirurgia (n=15) e um grupo com correção de defeitos ventrais por meio de sutura (n=21). Todas as avaliações foram realizadas com 1, 2 e 4 semanas de pós-operatório e constituíram-se de: avaliação da resposta aderencial por meio de pesquisa da área de prótese aderida e incidência de aderência a órgãos, avaliação biomecânica por meio de ensaios de tração de tiras de parede abdominal e avaliação morfométrica do tecido inflamatório e das fibras colagênicas em cortes histológicos corados por Hematoxilina-eosina e pelo método da Picrossírius-polarização, respectivamente. Os resultados mostraram que: a fração de volume de tecido inflamatório no grupo PP na primeira, segunda e quarta semanas foi respectivamente: 20%, 9% e 4% enquanto no grupo PTFEe: 30%, 16% e 16%. Houve diferença estatística na segunda e quarta semanas. A fração de volume de colágeno fibrilar no grupo PP foi respectivamente: 65%, 71% e 77%, na primeira, segunda e quarta semanas. No grupo PTFEe os valores foram: 55%, 66% e 68%, na primeira, segunda e quarta semanas. Da mesma forma, houve diferença estatística na segunda e quarta semanas. Na análise semiquantitativa do grau de agregação de colágeno foi observado diferença estatística apenas primeira semana de pós-operatório a favor do PP (3,24 x 1,40 p=0,022). As próteses induziram valores semelhantes de área aderida na primeira (67,85%-PP x 71,42%- PTFEe), segunda (60,71%-PP x 60,71%-PTFEe) e quarta semanas de pós-operatório (46,42% PP x 42,85% PTFEe). Quanto à presença de aderência a órgãos abdominais houve diferença entre as próteses apenas na primeira semana a favor do PTFEe: enquanto 85,7% dos animais no grupo PP apresentaram aderências à órgãos, esse índice foi de apenas 28,5% no grupo PTFEe. Os valores de força máxima obtidos nos ensaios biomecânicos de tração com a prótese de PP foram na primeira, segunda e quarta semanas: 20,54 N, 21,62 N e 26,23 N. No grupo PTFEe os valores na primeira, segunda e quarta semanas foram: 16,92 N, 23,12 N e 25,41 N. Foi observada diferença estatística na primeira semana de pós-operatório. A comparação entre os implantes protéticos de PP e PTFEe nas condições da presente pesquisa permitiu concluir: 1) A estimativa de área aderida à prótese foi semelhante independentemente do material implantado; 2) Com 1 semana de pós-operatório, o implante de PP demonstrou-se mais resistente aos ensaios biomecânicos de tração o que se correlacionou a um maior grau de agregação das fibras colagênicas nos tecidos implantados; 3) Com 1 semana de pós-operatório, os implantes de PTFEe induziram aderências as órgãos abdominais em um menor número de animais; 4) Com 2 e 4 semanas de pós-operatório o implante de PP induziu a uma menor infiltração de tecido inflamatório e a um maior depósito de colágeno fibrilar / Nowadays, abdominal wall defects are frequently repaired with biomaterials. Although utilized with good results for several decades, polypropylene mesh (PP) has been implicated with serious complications due to adhesion to the abdominal organs. It has been reported that prostheses of expanded polytetrafluoroethylene (ePTFE) mesh exhibit less adhesion formation potential; however, data obtained by biomechanical studies leave doubt as to its real efficiency in hernia repair. The objective of the present study was to compare these two types of mesh in the correction of ventral defects created in Wistar rats, taking into account histological and biomechanical parameters and the adhesion response. For the histological study, a group of animals (n = 21) was submitted simultaneously to subperitoneal implantation of fragments of PP and ePTFE mesh. For the comparative study of the biomechanical and adhesion response between the prostheses, subperitoneal implantation with PP (n = 21) and ePTFE mesh (n = 21) was performed to repair surgically created abdominal defects, involving all layers of the abdominal wall. In the biomechanical analysis, two other groups of animals were used for the control: a group not submitted to surgery (n = 15) and a group with abdominal wall defects repaired with sutures (n = 21). At postoperative weeks 1, 2 and 4, the following evaluations were performed: study of the adhesion response by measuring the incidence of adherence to organs and area of adhered prosthesis; biomechanical test of abdominal wall strips; and morphometric study of the inflammatory tissue and collagenic fibers in sections stained with hematoxylin-eosin and by Picrosiriuspolarization technique. The results showed that: the inflammatory tissue volume in group PP at postoperative weeks 1, 2 and 4, respectively, was 20%, 9% and 4%; while in the group ePTFE the values were 30%, 16% and 16%. The difference was statistically significant in postoperative weeks 1 and 4. The collagen fibril volume in group PP was: 65%, 71% and 77%, in postoperative weeks 1, 2 and 4, respectively. In group ePTFE the values were: 55%, 66% and 68%. Likewise, there was a statistically significant difference in postoperative weeks 2 and 4. In the semi-quantitative analysis of the degree of collagen aggregation, a statistically significant difference was only observed in postoperative week 1, in favor of PP (3.24 x 1.40, p = 0.022). The prostheses induced similar values for adhered area in postoperative week 1 (67.85%-PP vs. 71.42%-ePTFE), week 2 (60.71%-PP vs. 60.71%-ePTFE) and week four (46.42% PP vs. 42.85% ePTFE). Regarding the presence of adherence to abdominal organs, there was only a statistically significant difference between the prostheses in week one, in favor of ePTFE. While 85.7% of the animals in group PP presented adherence to organs, this index was only 28.5% in group ePTFE. The maximum force obtained in the biomechanical tests with the PP mesh was 20.54 N, 21.62 N and 26.23 N, in postoperative weeks 1, 2 and 4, respectively. In group ePTFE the values were 16.92 N, 23.12 N and 25.41 N. A statistically significant difference was observed in postoperative week 1. The comparison between PP and ePTFE prosthetic implants in the conditions of the present research enabled the conclusion that: 1) the estimated area adhered to the prostheses was similar, irrespective of the implanted material; 2) at postoperative week 1, the resistance to traction was higher when the repair was done with PP mesh, which was correlated to a higher degree of collagen fiber aggregation in the implanted tissues; 3) at postoperative week 1, fewer visceral adhesions were formed on ePTFE group of animals; and 4) at postoperative weeks 2 and 4, the PP implant induced a smaller infiltration of inflammatory tissue and a larger deposit of collagen fibrils