Inmunopatología de la brucelosis osteoarticular / Immunopathology of osteoarticular brucelosis

La brucelosis es una de las enfermedades zoonóticas más importantes a nivel mundial capaz de producir enfermedad crónica en los seres humanos. La localización osteoarticular es la presentación más común de la enfermedad activa en el hombre. Sin embargo, algunos de los mecanismos moleculares implicados en la enfermedad osteoarticular han comenzado a dilucidarse recientemente. Brucella abortus induce daño óseo a través de diversos mecanismos en los cuales están implicados TNF-α y RANKL. En estos procesos participan células inflamatorias que incluyen monocitos/macrófagos, neutrófilos, linfocitos T del tipo Th17 y linfocitos B. Además, B. abortus puede afectar directamente las células osteoarticulares. La bacteria inhibe la deposición de la matriz ósea por los osteoblastos y modifica el fenotipo de estas células para producir metaloproteinasas de matriz (MMPs) y la secreción de citoquinas que contribuyen a la degradación del hueso. Por otro lado, la infección por B. abortus induce un aumento en la osteoclastogénesis, lo que aumenta la resorción de la matriz ósea orgánica y mineral y contribuye al daño óseo. Dado que la patología inducida por Brucella afecta el tejido articular, se estudió el efecto de la infección sobre los sinoviocitos. Estos estudios revelaron que, además de inducir la activación de estas células para secretar quemoquinas, citoquinas proinflamatorias y MMPs, la infección inhibe la muerte por apoptosis de los sinoviocitos. Brucella es una bacteria intracelular que se replica en el retículo endoplásmico de los macrófagos. El análisis de los sinoviocitos infectados con B. abortus indicó que las bacterias también se multiplican en el retículo endoplasmático, lo que sugiere que la bacteria podría usar este tipo celular para la multiplicación intracelular durante la localización osteoarticular de la enfermedad. Los hallazgos presentados en esta revisión intentan responder a preguntas sobre los mediadores inflamatorios implicados en el daño osteoarticular causado por Brucella. (AU)

Brucellosis is one of the most important zoonotic diseases that can produce chronic disease in humans worldwide. Osteoarticular involvement is the most common presentation of human active disease. The molecular mechanisms implicated in bone damage have started to be elucidated. B. abortus induces bone damage through diverse mechanisms in which TNF-α and RANKL are implicated. These processes are driven by inflammatory cells, including monocytes/macrophages, neutrophils, Th17 lymphocytes and B cells. Also, Brucella abortus (B. abortus) can directly affect osteoarticular cells. The bacterium inhibits bone matrix deposition by osteoblast and modifies the phenotype of these cells to produce matrix methalloproteinases (MMPs) and cytokine secretion that contribute to bone matrix degradation. B. abortus also affects osteoclast increasing mineral and organic bone matrix resorption and contributing to bone damage. Since the pathology induced by Brucella species involves joint tissue, experiments conducted in sinoviocytes revealed that besides inducing the activation of these cells to secrete chemokines, proinflammatory cytokines and MMPS, the infection also inhibits sinoviocyte apoptosis. Brucella is an intracellular bacterium that replicate in the endoplasmic reticulum of macrophages. The analysis of B. abortus infected sinoviocytes indicated that bacteria also replicate in their reticulum suggesting that the bacterium could use this cell type for intracellular replication during the osteoarticular localization of the disease. The findings presented in this review try to answer key questions about the inflammatory mediators involved in osteoarticular damage caused by Brucella. (AU)

Necroptosis occurs in osteoblasts during tumor necrosis factor-α stimulation and caspase-8 inhibition

Necroptosis is a regulated cell death mechanism. However, it is unknown whether necroptosis is involved in the death of tumor necrosis factor-α (TNF-α)-treated osteoblasts. Therefore, we conducted the study with TNF-α, Nec-1 (a specific inhibitor of necroptosis), and Z-IETD-FMK (a specific inhibitor of apoptosis) to determine whether necroptosis plays a role in the death of TNF-α-treated osteoblast cell line MC3T3-E1. Cell viability, cell death, and lactate dehydrogenase (LDH) release were assayed to evaluate cytotoxicity. Specific marker proteins receptor interacting protein kinase (RIPK3) and phosphorylated mixed lineage kinase domain-like protein (p-MLKL) for necroptosis, and cleaved caspase 3 for apoptosis were detected by western blot, and mRNA was measured by quantitative real-time polymerase chain reaction (qRT-PCR). We found that TNF-α inhibited cell proliferation in a dose- and time-dependent manner. Nec-1 plus Z-IETD-FMK restored cell viability and significantly decreased LDH release. In addition, TNF-α alone increased the cell population of AV+PI−, while Z-IETD-FMK caused a shift in the cell population from AV+PI− to AV+PI+. Furthermore, TNF-α significantly increased protein cleaved caspase 3. TNF-α plus Z-IETD-FMK significantly increased the proteins RIPK3 and MLKL phosphorylation in MC3T3-E1 cells, while the changes in mRNA levels of RIPK3, MLKL, and caspase 3 were not consistent with the changes in the corresponding protein expression levels. In conclusion, TNF-α induced preferentially apoptosis in osteoblast cell line and necroptosis played a decisive role when TNF-α-induced death was inhibited by the inhibitor of apoptosis. Combined treatment with Nec-1 and Z-IETD-FMK protected mouse osteoblasts from death induced by TNF-α.

Osteoporosis and autophagy: What is the relationship? / Osteoporose e autofagia: qual é a relação?

Summary Autophagy is a survival pathway wherein non-functional proteins and organelles are degraded in lysosomes for recycling and energy production. Therefore, autophagy is fundamental for the maintenance of cell viability, acting as a quality control process that prevents the accumulation of unnecessary structures and oxidative stress. Increasing evidence has shown that autophagy dysfunction is related to several pathologies including neurodegenerative diseases and cancer. Moreover, recent studies have shown that autophagy plays an important role for the maintenance of bone homeostasis. For instance, in vitro and animal and human studies indicate that autophagy dysfunction in bone cells is associated with the onset of bone diseases such as osteoporosis. This review had the purpose of discussing the issue to confirm whether a relationship between autophagy dysfunction and osteoporosis exits.

Resumo A autofagia é uma via de sobrevivência celular pela qual proteínas e organelas não funcionais são degradadas nos lisossomos, para reciclagem e geração de energia. Assim, a autofagia é fundamental para a manutenção da homeostase e viabilidade da célula, agindo como um controle de qualidade que evita o acúmulo de estruturas desnecessárias e o estresse oxidativo. Um número crescente de estudos tem demonstrado que disfunções na via autofágica estão relacionadas ao surgimento de diversas doenças, como as neurodegenerativas e o câncer. Estudos também têm indicado que a autofagia exerce um importante papel para a manutenção da homeostase óssea; por exemplo, estudos in vitro e em animais e humanos mostram que disfunções da autofagia nas células ósseas estão associadas ao surgimento de doenças ósseas, como a osteoporose. Nesta revisão, foram abordados esses estudos, a fim de melhor esclarecer se há uma relação entre disfunção autofágica e osteoporose.

The role of Osterix protein in the pathogenesis of peripheral ossifying fibroma

Abstract Peripheral ossifying fibroma (POF) is a reactive lesion of oral tissues, associated with local factors such as trauma or presence of dental biofilm. POF treatment consists of curettage of the lesion combined with root scaling of adjacent teeth and/or removal of other sources of irritants. This study aimed to analyze the clinical and pathological features of POF and to investigate the immunoexpression of Osterix and STRO-1 proteins. Data such as age, gender, and size were obtained from 30 cases of POF. Microscopic features were assessed by conventional light microscopy using hematoxylin-eosin staining and immunohistochemical markers, and by polarized light microscopy using Picrosirius red staining. The age range was 11-70 years and 70% of the patients were female. Moreover, the size of POF varied from 0.2 to 5.0 cm; in 43.33% of the cases, the mineralized content consisted exclusively of bony trabeculae. The immunohistochemical analysis showed nuclear staining for Osterix in 63% and for STRO-1 in 20% of the cases. Mature collagen fibers were observed in mineralized tissue in 76.67% of the cases. The clinical and microscopic features observed were in agreement with those described in the literature. Osterix was overexpressed, while STRO-1 was poorly expressed. Osterix was expressed particularly in cells entrapped in and around mineralized tissue, indicating the presence of a stimulus that triggers the differentiation of these cells into osteoblasts or cementoblasts, i.e., cells that produce mineralized tissue. Based on our results, Osterix may play a role in the pathogenesis of POF.

Effect of supplementary zinc on orthodontic tooth movement in a rat model

ABSTRACT Introduction: Osteoclasts and osteoblasts are responsible for regulating bone homeostasis during which the trace element zinc has been shown to exert a cumulative effect on bone mass by stimulating osteoblastic bone formation and inhibiting osteoclastic bone resorption. Objective: The aim of the present study was to investigate the effects of zinc (Zn) on orthodontic tooth movement (OTM) in a rat model. Material and Methods: A total of 44 male Wistar rats were divided into four groups of 11 animals each and received 0, 1.5, 20 and 50 ppm Zn in distilled water for 60 days. In the last 21 days of the study, nickel-titanium closed coil springs were ligated between maxillary right incisors and first molars of all rats, and tooth movement was measured at the end of this period. Histological analysis of hematoxylin/eosin slides was performed to assess root resorption lacunae, osteoclast number and periodontal ligament (PDL) width. Results: Mean OTM was calculated as 51.8, 49.1, 35.5 and 45 µm in the 0, 1.5, 20 and 50 ppm zinc-receiving groups, respectively. There were no significant differences in neither OTM nor histological parameters among the study groups (p > 0.05). Conclusion: According to the results obtained in the current investigation, increase in supplementary zinc up to 50 ppm does not affect the rate of OTM neither bone and root resorption in rats.

RESUMO Introdução: os osteoclastos e os osteoblastos são responsáveis por regular a homeostase óssea, processo no qual o oligoelemento zinco tem demonstrado exercer um efeito cumulativo sobre a massa óssea, estimulando a formação óssea osteoblástica e inibindo a reabsorção óssea osteoclástica. Objetivo: o objetivo do presente estudo foi investigar os efeitos do zinco (Zn) sobre a movimentação dentária ortodôntica (MDO) em ratos. Métodos: um total de 44 ratos Wistar machos foi dividido em quatro grupos de 11 animais cada, os quais receberam 0; 1,5; 20 e 50ppm de zinco diluído em água destilada, durante 60 dias. Nos últimos 21 dias do estudo, molas helicoidais fechadas de níquel-titânio foram instaladas entre os incisivos direitos e os primeiros molares superiores de todos os ratos, e a movimentação dentária foi medida ao final desse período. Foi realizada análise histológica de cortes corados por hematoxilina-eosina, para avaliar as lacunas de reabsorção radicular, o número de osteoclastos e a espessura do ligamento periodontal. Resultados: as médias da MDO foram estimadas em 51,8; 49,1; 35,5 e 45µm no grupos que receberam, respectivamente, 0; 1,5; 20 e 50ppm de zinco. Não houve diferença significativa entre os grupos experimentais, nem quanto à MDO, nem quanto aos parâmetros histológicos (p > 0,05). Conclusão: segundo os resultados obtidos na presente investigação, verificou-se que um aumento na dose de suplementação com zinco para 50ppm não afeta nem o índice de MDO, nem a reabsorção óssea ou radicular em ratos.

Primary osteosarcoma of the breast: pathological and imaging findings / Osteossarcoma primário da mama: achados patológicos e de imagem

SUMMARY Primary osteosarcoma of the breast (POB) is an extremely rare and aggressive tumor. Differential diagnosis of POB includes osteosarcoma of the chest wall and metaplastic breast carcinoma. Imaging tests that exclude the existence of a direct connection between the tumor and chest wall, as well as histopathological and immunohistochemical studies that rule out the presence of an epithelial component are required for the diagnosis of POB. We report a case of a 69-year old woman with POB. Imaging and pathological findings are presented. Therapeutic approach is discussed in the light of current knowledge, including potential complications.

RESUMO O osteossarcoma primário da mama (OPM) é um tumor extremamente raro e agressivo. O diagnóstico diferencial do OPM inclui o osteossarcoma da parede torácica e o carcinoma metaplásico da mama. Exames de imagem que excluam a existência de uma conexão direta entre o tumor e a parede torácica, e estudos histopatológico e imuno-histoquímico que descartem a presença de um componente epitelial são necessários para o diagnóstico de OPM. Relatamos um caso de OPM em uma mulher de 69 anos de idade. Os achados de imagem e patológicos são apresentados. A abordagem terapêutica é discutida à luz do conhecimento atual, incluindo potenciais complicações.

The negative prognostic impact of bone metastasis with a tumor mass

OBJECTIVE: Typically, bone metastasis causes osteolytic and osteoblastic lesions resulting from the interactions of tumor cells with osteoclasts and osteoblasts. In addition to these interactions, tumor tissues may grow inside bones and cause mass lesions. In the present study, we aimed to demonstrate the negative impact of a tumor mass in a large cohort of patients with bone metastatic cancer. METHODS: Data from 335 patients with bone metastases were retrospectively reviewed. For the analysis, all patients were divided into three subgroups with respect to the type of bone metastasis: osteolytic, osteoblastic, or mixed. The patients were subsequently categorized as having bone metastasis with or without a tumor mass, and statistically significant differences in median survival and 2-year overall survival were observed between these patients (the median survival and 2-year overall survival were respectively 3 months and 16% in patients with a tumor mass and 11 months and 26% in patients without a tumor mass; p<0.001). RESULTS: According to multivariate analysis, the presence of bone metastasis with a tumor mass was found to be an independent prognostic factor (p=0.011, hazard ratio: 1.62, 95% confidence interval: 1.11–1.76). Bone metastasis with a tumor mass was more strongly associated with osteolytic lesions, other primary diseases (except for primary breast and prostate cancers), and spinal cord compression. CONCLUSION: Bone metastasis with a tumor mass is a strong and independent negative prognostic factor for survival in cancer patients. .

In vitro culture and characterization of alveolar bone osteoblasts isolated from type 2 diabetics

In order to understand the mechanisms of poor osseointegration following dental implants in type 2 diabetics, it is important to study the biological properties of alveolar bone osteoblasts isolated from these patients. We collected alveolar bone chips under aseptic conditions and cultured them in vitro using the tissue explants adherent method. The biological properties of these cells were characterized using the following methods: alkaline phosphatase (ALP) chemical staining for cell viability, Alizarin red staining for osteogenic characteristics, MTT test for cell proliferation, enzyme dynamics for ALP contents, radio-immunoassay for bone gla protein (BGP) concentration, and ELISA for the concentration of type I collagen (COL-I) in the supernatant. Furthermore, we detected the adhesion ability of two types of cells from titanium slices using non-specific immunofluorescence staining and cell count. The two cell forms showed no significant difference in morphology under the same culture conditions. However, the alveolar bone osteoblasts received from type 2 diabetic patients had slower growth, lower cell activity and calcium nodule formation than the normal ones. The concentration of ALP, BGP and COL-I was lower in the supernatant of alveolar bone osteoblasts received from type 2 diabetic patients than in that received from normal subjects (P < 0.05). The alveolar bone osteoblasts obtained from type 2 diabetic patients can be successfully cultured in vitro with the same morphology and biological characteristics as those from normal patients, but with slower growth and lower concentration of specific secretion and lower combining ability with titanium than normal ones.

In vivo bone response and interfacial properties of titanium-alloy implant with different designs in rabbit model with time.

Background: Using implants for dental applications are well-accepted procedures as one of the solutions for periodontal defect repair. Suitable design and materials, their reaction with the surrounding hard tissues and interfacial biomechanical properties are still considered to be the primary criteria which need to be addressed systematically. In the present study, a thorough and systemic approach was made to identify a suitable implant, considering the above criteria after both in vitro and in vivo animal trials. Materials and Methods: Titanium alloy (Ti-6Al-4V) implants, with thread and without thread models, were implanted to the mid-metaphysial portion of the tibia of the right hind leg of three white Australian Chinchilla rabbit species and their effects and response to the surrounding bone were investigated. Parameters studied included hematological and biochemical features (serum alkaline phosphatase and calcium), both preoperatively and postoperatively, consecutively for 7 days and after 1-3 months. The interfacial integrity and compositional variation along the interface were studied using scanning electron microscope (SEM) with energy dispersive analysis of X-ray (EDAX) and histopathology from 1 to 3 months consecutively. Finally, biomechanical properties were studied with the help of push-out test. Results: Bone remineralization started through the process of electro-physiological ionic exchanges, which helps in formation of osteoblastic cells in the area of bony injury. The SEM-EDAX results confirmed the initial stability for the Ti (with thread) implant, but the regeneration of new bone formation was faster in the case of Ti (Without thread) implant, and hence could be used for faster healing. These have also been substantiated through push-out and histopathlogical tests. Conclusion: From the physico-chemical and biomechanical observations, it was found that that smooth type implants were well accepted in the physiological condition although chances of elemental leaching from the surface were also observed. Increase of the surface roughness can help into the formation of physico-chemical bondage with the surrounding hard tissues.

Disturbed Osteoblastic Differentiation of Fibrous Hamartoma Cell from Congenital Pseudarthrosis of the Tibia Associated with Neurofibromatosis Type I

BACKGROUND: Fibrous hamartoma is the key pathology of congenital pseudarthrosis of the tibia (CPT), which was shown to have low osteogenicity and high osteoclastogenicity. This study further investigated the mechanism of impaired osteoblastic differentiation of fibrous hamartoma cells. METHODS: Fibroblast-like cells were obtained from enzymatically dissociated fibrous hamartomas of 11 patients with CPT associated with neurofibromatosis type I (NF1). Periosteal cells were also obtained from the distal tibial periosteum of 3 patients without CPT or NF1 as control. The mRNA levels of Wnt ligands and their canonical receptors, such as Lrp5 and beta-catenin, were assayed using reverse transcriptase PCR (RT-PCR). Changes in mRNA expression of osteoblast marker genes by rhBMP2 treatment were assayed using quantitative real time RT-PCR. Changes in mRNA expression of transcription factors specifically involved in osteoblastic differentiation by rhBMP2 treatment was also assayed using quantitative real-time RT-PCR. RESULTS: Wnt1 and Wnt3a mRNA expression was lower in fibrous hamartoma than in tibial periosteal cells, but their canonical receptors did not show significant difference. Response of osteoblastic marker gene expression to rhBMP2 treatment showed patient-to-patient variability. Col1a1 mRNA expression was up-regulated in most fibrous hamartoma tissues, osteocalcin was up-regulated in a small number of patients, and ALP expression was down-regulated in most fibrous hamartoma tissues. Changes in mRNA expression of the transcription factors in response to rhBMP2 also showed factor-to-factor and patient-to-patient variability. Dlx5 was consistently up-regulated by rhBMP2 treatment in all fibrous hamartoma tissues tested. Msx2 expression was down-regulated by rhBMP2 in most cases but by lesser extent than control tissue. Runx2 expression was up-regulated in 8 out of 18 fibrous hamartoma tissues tested. Osterix expression was up-regulated in 2 and down-regulated in 3 fibrous hamartoma tissues. CONCLUSIONS: Congenital pseudarthrosis of the tibia appears to be caused by fibrous hamartoma originating from aberrant growth of Nf1 haploinsufficient periosteal cells, which failed in terminal osteoblastic differentiation and arrested at a certain stage of this process. This pathomechanism of CPT should be targeted in the development of novel therapeutic biologic intervention.

Consideraciones en el tratamiento odontológico de pacientes en terapia con bifosfonatos / Considerations in the dental treatment of patients on bisphosphonate therapy

Los bifosfonatos son fármacos de gran utilidad en el diagnóstico y tratamiento de ciertas enfermedades metabólicas óseas. Son utilizados en el tratamiento de mielomas múltiples, metástasis óseas y la hipercalcemia maligna, así como en la prevención y tratamiento de enfermedades del sistema óseo esquelético como la enfermedad de Paget y especialmente la osteoporosis. El objetivo de este artículo es presentar las consideraciones para el tratamiento odontológico de pacientes que van a iniciar o se encuentran en terapia con bifosfonatos a fin de ofrecerles las mejores alternativas terapéuticas que garanticen el correcto manejo de los tejidos bucales y mejorar su calidad de vida

Bisphosphonates are drugs useful in the diagnosis and treatment of certain metabolic bone diseases. This used in the treatment of multiple myeloma, bone metastases and malignant hypercalcemia and in the prevention and treatment of bones diseases skeletal system such as Paget diseases especially osteoporosis. The aim of this paper is to present considerations for dental treatment of patients that will begin or are in bisphosphonate therapy in order to provide the best treatment options to ensure the proper management of the oral tissues and improve their quality of life

Enhanced bone apposition to Brazilian microrough titanium surfaces

It has recently been reported that machined and microrough (micro) Brazilian titanium (Ti) implants have good production standards. The aim of this study was to evaluate in vivo bone formation around 2 different implant surfaces placed in dog's mandible. Thirty-two screw-typed Ti implants were used in this study. Mandibular premolars were extracted in 8 dogs and, after 12 weeks, 2 machined (Neodent Titamax, Brazil) and 2 micro implants (Neodent Titamax Porous, Brazil) were placed in each animal. Biopsies were taken at 3 and 8 weeks post-implantation and stained with Stevenel's blue and Alizarin red for histomorphometric measurements of bone-to-implant contact (BIC), bone area between threads (BABT) and bone area within the mirror area (BAMA). Data were analyzed statistically by two-way ANOVA (á=0.05). While at 3 weeks micro implants exhibited significantly more BIC than machined ones (55 ± 12.5 percent and 35.6 ± 15 percent, p<0.05), no significant difference in such parameter was detected at 8 weeks (51.2 ± 21 percent and 48.6 ± 18.1 percent, p>0.05). There were no significant differences in BABT and BAMA between the implants. Micro surfaces promoted higher contact osteogenesis. These data indicate that this commercial micro Ti implant surface enhances contact osteogenesis at an early post-implantation period when compared to the machined one.

Estudos recentes demonstram que implantes nacionais de titânio (Ti) usinados e micro-rugosos apresentam padrões adequados de produção. O objetivo deste estudo foi de avaliar a neo-formação óssea in vivo em 2 tipos diferentes de implantes colocados em mandíbulas de cães. Trinta e dois implantes rosqueáveis de Ti foram utilizados neste estudo. Os pré-molares mandibulares de 8 cães foram extraídos e, após 12 semanas, 2 implantes usinados (Neodent Titamax) e 2 implantes micro-rugosos (Neodent Titamax Porous) foram colocados em cada animal. Após 3 e 8 semanas da implantação os espécimes foram biopsiados, corados com Stevenel's blue e Alizarin red e analisados histomorfometricamente quanto à porcentagem de contato-osso-implante (COI), área de osso mineralizado entre as roscas (OMER) e área de osso mineralizado na área em espelho (OMAE). Os resultados foram analisados estatisticamente pelo teste de ANOVA a dois fatores. Os implantes micro-rugosos apresentaram maior COI do que os implantes controle em 3 semanas (55,0 ± 12,5 por cento e 35,6 ± 15,0 por cento; p<0,05), enquanto não houve diferença em 8 semanas (51,2 ± 21,0 por cento e 48,6 ± 18,1 por cento; p>0,05). Não houve diferença quanto ao OMER e OMAE. Esses dados nos indicaram que os implantes micro-rugosos utilizados neste estudo aumentam a osteogênese de contato nos períodos iniciais pós-implantação quando comparados com implantes usinados.

Effects of platelet-rich plasma on healing of alveolar socket: Split-mouth histological and histometric evaluation in Cebus apella monkeys.

Context: The prediction of implant treatment is directly influenced by the quality of the remaining bone after tooth extraction. Aims : The purpose of this experimental study was to, histologically and histometrically, evaluate the bone repair process in the central areas of extraction sockets filled with platelet-rich plasma. Materials and Methods: Four young adult male Cebus apella monkeys were used. The extraction of both right and left inferior second premolars was accomplished. After extraction, in one of the extraction sockets, coagulum was maintained while in the other it was removed; the alveolus was dried with gauze compress and filled up with platelet concentrate. For PRP production, Sonnleitner's protocol was followed. The specimens for histological and histometric assessment were obtained in 30, 90, 120 and 180 days intervals. Results: In 30 days new bone formation was intense in both experimental and control sockets and no significant differences were observed between the two groups. After 90 days of the extraction, while the control group showed signs of decrease in osteogenesis, in the experimental unit, the process of bone formation and fibroblast-like cell proliferation remained intense. After 120 days, the PRP treated socket was occupied by large trabeculae of bone. After 180 days, the control unit was occupied mostly with bone marrow. The experimental unit remained occupied with large amounts of bone tissue. Conclusions: It was possible to conclude that bone repair was enhanced by the use of platelet- rich plasma in alveolar sockets.

Histometric study of alveolar bone in rats submitted to ethanol during lactation

The present work studied the adverse effects of maternal exposure of rats to alcohol during lactation, on the development of their off spring. Histometric evaluation by karyometry and of the alveolar bone at the level of the first upper molar of the sucking was perfomed. Two groups of animals, one coming from mothers exposed to drinking water containing 20 percent ethanol during the total lactation period and the other of controls coming from mothers receiving only alcohol-free drinking water during this period. On the 21 first day of lactation the young of each group were aleatorily selected and following anesthesia, their heads severed; after histological treatment, serial 6 ìm sections on the frontal plane at the molar level, stained with hematoxilin and eosin, were obtained. The experimental results produced, suggest that sucking from ethanol-treated mothers, show retarded post-natal growth, their alveolar bones presenting scarce, little calcified trabeculae, and a more abundant bone marrow compared to controls.

Considerando que la lactancia es un período importante y vulnerable, y que la exposición materna al alcohol durante esta fase puede provocar efectos adversos en las crías en desarrollo, el propósito del presente trabajo es evaluar histométricamente (mediante cariometría y estereología), el hueso alveolar a nivel del primer molar superior, de ratas lactantes sometidas a los efectos del etanol. Con esa finalidad utilizamos dos grupos, uno que recibió etanol al 20 por ciento en el bebedero, durante todo el período de lactancia (21días), y otro que recibió solo agua. En el 21° día de lactancia, 5 ratas de cada grupo fueron aleatoriamente seleccionadas. Después de sacrificados, los animales fueron fijados en formol al 10 por ciento. Las cabezas, separadas de los cuerpos, fueron incluidas en parafina, y cortadas seriadamente con 6 Lim de grosor, a partir de un plano frontal al nivel de los molares, y teñidas con hematoxilina y eosina. Basados en los resultados presentes, es posible concluir que el etanol al 20 por ciento en el agua de beber, administrado a ratas lactantes, provoca los siguientes efectos: reducción significativa del peso corporal, alteraciones de las trabéculas del hueso alveolar, observadas estereológicamente, evidenciadas por trabéculas delicadas y poco calcificadas, con médula abundante, núcleos menores en osteoblastos y osteocitos y más achatados en los primeros, y con osteocitos de volúmenes citoplasmático y celular menor y densidad numérica mayor.

Bone regeneration after demineralized bone matrix and castor oil (Ricinus communis) polyurethane implantation

Innocuous biocompatible materials have been searched to repair or reconstruct bone defects. Their goal is to restore the function of live or dead tissues. This study compared connective tissue and bone reaction when exposed to demineralized bovine bone matrix and a polyurethane resin derived from castor bean (Ricinus communis). Forty-five rats were assigned to 3 groups of 15 animals (control, bovine bone and polyurethane). A cylindrical defect was created on mandible base and filled with bovine bone matrix and the polyurethane. Control group received no treatment. Analyses were performed after 15, 45 and 60 days (5 animals each). Histological analysis revealed connective tissue tolerance to bovine bone with local inflammatory response similar to that of the control group. After 15 days, all groups demonstrated similar outcomes, with mild inflammatory reaction, probably due to the surgical procedure rather than to the material. In the polymer group, after 60 days, scarce multinucleated cells could still be observed. In general, all groups showed good stability and osteogenic connective tissue with blood vessels into the surgical area. The results suggest biocompatibility of both materials, seen by their integration into rat mandible. Moreover, the polyurethane seems to be an alternative in bone reconstruction and it is an inexhaustible source of biomaterial.

Bone response to a Ca- and P-enriched titanium surface obtained by anodization

This study evaluated bone response to a Ca- and P- enriched titanium (Ti) surface treated by a multiphase anodic spark deposition coating (BSP-AK). Two mongrel dogs received bilateral implantation of 3 Ti cylinders (4.1 x 12 mm) in the humerus, being either BSP-AK treated or untreated (machined - control). At 8 weeks postimplantation, bone fragments containing the implants were harvested and processed for histologic and histomorphometric analyses. Bone formation was observed in cortical area and towards the medullary canal associated to approximately 1/3 of implant extension. In most cases, in the medullary area, collagen fiber bundles were detected adjacent and oriented parallel to Ti surfaces. Such connective tissue formation exhibited focal areas of mineralized matrix lined by active osteoblasts. The mean percentages of bone-to-implant contact were 2.3 (0.0-7.2 range) for BSP-AK and 0.4 (0.0-1.3 range) for control. Although the Mann-Whitney test did not detect statistically significant differences between groups, these results indicate a trend of BSP-AK treated surfaces to support contact osteogenesis in an experimental model that produces low bone-to-implant contact values.

O objetivo desse estudo foi avaliar a resposta do tecido ósseo à superfície de titânio (Ti) enriquecida com Ca e P obtida por anodização (BSP-AK). Três cilindros de Ti (4,1 x 12 mm) BSP-AK ou usinado (controle) foram implantados bilateralmente nos úmeros de dois cães de raça indefinida. Oito semanas após a implantação, os fragmentos ósseos contendo os implantes foram removidos e processados para análises histológica e histomorfométrica. A formação óssea foi observada na região cortical e no canal medular até aproximadamente um terço da extensão do implante. Na maioria dos casos, feixes de fibras colágenas dispostos paralelamente à superfície do implante foram observados na região medular. Nessa região observaram-se também áreas focais de formação de matriz mineralizada e osteoblastos ativos. Os implantes do grupo BSP-AK apresentaram média de contato osso-implante 2,3 por cento, com medidas variando de 0,0 a 7,2 por cento e os do grupo controle tiveram média 0,4 por cento, com medidas variando de 0,0 a 1,3 por cento. Apesar do teste de Mann-Whitney não mostrar diferença estatisticamente significante entre os grupos, nossos resultados indicaram uma tendência para a ocorrência de osteogênese de contato na superfície BSP-AK em um modelo experimental que resulta em baixos valores de contato osso-implante.

Effect of 650 nm low-power laser on bone morphogenetic protein in bone defects induced in rat femors

PURPOSE:To investigate the influence of 650 nm GaAlAs laser on the action of bone morphogenetic protein (BMP) in bone defects produced in rat femurs. METHODS: The sample consisted of 12 male albino Wistar rats (Rattus norvegicus). The animals were randomly divided into four experimental groups. After undergoing anesthesia, the fur was removed from the lateral face of the right thigh and surgical dissection was performed to view the femur region. A bone defect was created using a spherical diamond-tipped drill bit. In groups 1 and 2, the defect was filled with a paste of Gen-Tech bone-inducing substance. The animals were treated with GaAlAs laser, at a predetermined dose of joules/cm² for 80 seconds, over an area of 1 cm². Groups 2 and 4 were used as controls. Bone samples were removed to perform histological procedures and morphometric analyses on the 7th, 14th and 21st days after the operation. The results obtained were subjected to statistical analysis using ANOVA variance according to two criteria, with four repetitions, followed by the post hoc t test. The rejection level for the nullity hypothesis was 0.05 or 5 percent (alpha <= 0.05). RESULTS: In comparisons between G1, G2, G3 and G4, p = 0.024 was observed. In statistical comparisons using the t test for paired samples, only G1 vs. G4 presented a statistically significant result (p = 0.021). CONCLUSION: The association of low-power laser application and Gen-Tech bone-inducing substance achieved a better result than laser application alone or BMP use alone.

OBJETIVO: Este trabalho tem como objetivo estudar comparativamente a influência do laser AsGaAl de 650nm sobre a ação das proteínas morfogenéticas ósseas( BMP) em defeitos ósseos produzidas em fêmures de ratos. METODOLOGIA: Utilizamos uma amostra composta por 12 ratos machos (Rattus norvegicus), de linhagem Wistar albino, mantidos confinados em caixas com temperatura ambiente constante e iluminação adequada. Os animais foram divididos aleatoriamente em 4 grupos experimentais. Após o procedimento anestésico, foi realizada a retirada dos pelos da face lateral da coxa direita, seguida de procedimento cirúrgico para permitir a visualização da região. Foi realizado um defeito ósseo empregando brocas diamantadas do tipo esférica. Nos grupos 1 e 2 o defeito foi preenchido com uma pasta formada por substância osteoindutora Gen - Tech. Os animais foram tratados com o Laser GaAlAs, com dose pré-determinada de 4 joules/cm² e tempo de 80 segundos para uma área de 1cm². Os grupos 2 e 4 foram adotados como grupo-controle. As amostras do osso foram retiradas para realização de procedimento histológico e análise morfométrica nos 7°,14°e 21° dias de pós-operatório. Os resultados obtidos foram submetidos à análise estatística pela variância ANOVA segundo dois critérios, com quatro repetições. Seguido do post hoc test de t teste, com nível de rejeição da hipótese de nulidade de 0,05 ou 5 por cento (alfa <= 0,05). RESULTADOS: Na comparação entre G1, G2, G3 e G4, observou-se: (P = 0,024) e durante a comparação estatística através do teste "t" para amostras pareadas apenas o cruzamento entre Grupo 1 vs. o Grupo 4 apresentou, resultado estatisticamente significante com (p=0,021). CONCLUSÃO: Concluímos que a associação da aplicação do laser de baixa potência e a substância osteoindutora Gen Tech alcançou melhor resultado do que do que a aplicação de laser ou apenas o uso das BMPs.

Influence of simvastatin on bone regeneration of tibial defects and blood cholesterol level in rats

The purpose of this study was to evaluate the effects of simvastatin, by oral or subcutaneous administration, on tibial defects regeneration and blood cholesterol level in rats. A surgical defect was made on the right tibia of 40 male animals assigned to 4 groups (n=10), based on two routes of administration and on the use or not of simvastatin: subcutaneous injection of simvastatin (7 mg/kg) (group AT) or only the vehicle of drug suspension (group AC), above the defect area, for 5 days; and 20 mg/kg of simvastatin macerated on water (group BT) or only water (group BC), orally, daily, during the whole observation period. The animals were sacrificed after 15 or 30 days, when blood samples were analyzed to check plasma cholesterol levels. Tibiae were removed and, after decalcification and routine laboratorial processing, histological and histomorphometrical analyses were carried out. ANOVA was used for statistical analysis at 5 percent signficance level. The histological and histomorphometrical analyses showed significant differences only between the experimental periods (p<0.05). Animals sacrificed after 30 days showed better bone repair (p<0.05). There was no statistically significant difference (p>0.05) for blood cholesterol levels between the groups. In conclusion, simvastatin administration either orally or subcutaneously did not improve bone repair of experimental tibial defects and did not alter blood cholesterol levels in rats.

Este estudo avaliou a influência da sinvastatina, administrada por via oral ou subcutânea, na reparação de defeitos ósseos em tíbia e nos níveis de colesterol sangüíneo, em ratos. Foram realizados defeitos cirúrgicos nas tíbias direitas de 40 ratos machos, distribuídos em 4 grupos (n=10), tomando-se como base duas vias de administração e o uso ou não de sinvastatina: injeção subcutânea de sinvastatina (7 mg/kg) (grupo AT) ou apenas do veículo de suspensão da droga (grupo AC), sobre a região do defeito, durante 5 dias; 20 mg/kg de sinvastatina (grupo BT) ou água filtrada (grupo BC) via oral, diariamente, durante todo o período de observação. Os animais foram sacrificados após 15 ou 30 dias, quando amostras sangüíneas foram colhidas para análise do nível de colesterol. As tíbias foram removidas e, após descalcificação e procedimentos laboratoriais de rotina, procedeu-se à análise histológica e histomorfométrica. Para avaliação estatística utilizou-se ANOVA com nível de significância de 5 por cento. As análises histomorfométrica e histológica mostraram diferença entre os grupos apenas com relação ao período experimental (p<0,05), apresentando os melhores resultados os animais sacrificados em 30 dias (p<0,05). Quanto ao nível de colesterol sangüíneo, não houve diferença estatisticamente significante entre os grupos analisados (p>0,05). Concluiu-se que, nas condições utilizadas, a sinvastatina, administrada via oral ou subcutânea, não exerceu efeito estimulador sobre o reparo ósseo de defeitos experimentais em tíbias de ratos e não alterou os níveis de colesterol sangüíneo.

Effect of synthetic cell- binding peptide on the healing of cortical segmental bone defects

To determine the effect of inorganic bone matric/Pepgen P-15 [ABM/P-15] on the healing of a critical sized segmental defect in a rat radius using a radiological and histological grading system. We carried out this study at the Research Laboratories, Gazi University School of Medicine in 2004. Critical sized segmental defects were created in the radius of 36 Wistar rats. Thirteen defects were filled with ABM/P-15 Flow [gel form], 12 defects were filled with ABM/P-15, and 11 defects were used as a control group. The rats were sacrified at the tenth week, and healing of the defects was evaluated radiographically and histologically. The usage of ABM/P-15 and ABM/P-15 Flow were demonstrated to improve healing of segmental bone defects compared with the control group. Statistical evaluation showed that there were significant differences between control sites, and the sites treated with P-15 and P-15 Flow [p=0.011]. The highest radiological and histological grades were achieved by P-15. Segmental cortical bone defects may be treated with ABM/P-15 instead of bone allografts, and autografts. According to the radiological and histological parameters measured in this study, the implantation of ABM/P-15 resulted in optimum healing of the segmental cortical bone defects. Pepgen P-15 has a positive effect on bone healing, without any immunogenic features and disease transmission risk. Therefore, ABM/P-15 can also be used for orthopedic surgery