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BACKGROUND: The resistivity index (RI) evaluates haemodynamic based on arterial resistance. Alterations in renal blood flow are important for the early detection of kidney damage, as perfusion might be one of the first affected aspects. OBJECTIVES: To retrieve published studies on equine renal RI to develop a standardised method of renal ultrasonographic examination and to evaluate the current reference range for the renal RI in horses. STUDY DESIGN: Systematic review. METHODS: An electronic search in Science Direct, PubMed, Scopus and Web of Science databases was performed in February 2023 using the terms 'RI' OR 'resistivity index' OR 'IP' OR 'pulsatility index' AND (kidney OR renal) AND (equine OR horse) in titles, keywords and abstracts. The studies were screened for inclusion based on pre-determined criteria and data on the variables of interest were collected from included studies. The SYRCLE risk of bias tool was used to assess the methodological quality. RESULTS: The electronic searches identified 134 studies, of which 5 were eligible for inclusion in this review. The studies had been conducted in healthy non-sedated horses through the transabdominal technique. The upper limit of normality for the renal RI was 0.58 ± 0.06 for the right kidney of untrained horses, which is considerably lower than the value of 0.70 currently used for humans, cats and dogs. There were heterogenous outcomes among the studies: two of the five demonstrated a difference between the right and left renal RI values, and one of the five showed an increased renal RI in elderly horses compared with foals and adult horses. MAIN LIMITATIONS: Data regarding the RI in horses are still scarce. CONCLUSIONS: Additional studies that establish a reference range for the renal RI in horses are needed and there is a need to ensure consistency of techniques.
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BACKGROUND: Under the adverse remodeling of the right ventricle and interventricular septum in pulmonary arterial hypertension (PAH) the left ventricle (LV) dynamics is impaired. Despite the benefits of combined aerobic and resistance physical trainings to individuals with PAH, its impact on the LV is not fully understood. OBJECTIVE: To test whether moderate-intensity combined physical training performed during the development of PAH induced by MCT in rats is beneficial to the LV's structure and function. METHODS: Male Wistar rats were divided into two groups: Sedentary Hypertensive Survival (SHS, n = 7); and Exercise Hypertensive Survival (EHS, n = 7) to test survival. To investigate the effects of combined physical training, another group of rats were divided into three groups: Sedentary Control (SC, n = 7); Sedentary Hypertensive (SH, n = 7); and Exercise Hypertensive (EH, n = 7). PAH was induced through an intraperitoneal injection of MCT (60 mg/kg). Echocardiographic evaluations were conducted on the 22nd day after MCT administration. Animals in the EHS and EH groups participated in a combined physical training program, alternating aerobic (treadmill running: 50 min, 60% maximum running speed) and resistance (ladder climbing: 15 climbs with 1 min interval, 60% maximum carrying load) exercises, one session/day, 5 days/week for approximately 4 weeks. RESULTS: The physical training increased survival and tolerance to aerobic (i.e., maximum running speed) and resistance (i.e., maximum carrying load) exertions and prevented reductions in ejection fraction and fractional shortening. In addition, the physical training mitigated oxidative stress (i.e., CAT, SOD and MDA) and inhibited adverse LV remodeling (i.e., Collagen, extracellular matrix, and cell dimensions). Moreover, the physical training preserved the amplitude and velocity of contraction and hindered the reductions in the amplitude and velocity of the intracellular Ca2+ transient in LV single myocytes. CONCLUSION: Moderate-intensity combined physical training performed during the development of MCT-induced PAH in rats protects their LV from damages to its structure and function and hence increases their tolerance to physical exertion and prolongs their survival.
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Pulmonary arterial hypertension (PAH) is characterized by elevated arterial pressure and vascular resistance. PAH may cause alterations in the microcirculation of several organs, including the kidney, liver, brain, and testes. However, it remains unclear whether monocrotaline-induced PAH exerts detrimental effects on animal testes. Thus, we analyzed the impact of PAH on testicular morphology and function. Additionally, we investigated the effect of resistance exercise training (RT) on testicular parameters in PAH rats. Eight healthy Wistar rats and eight PAH rats were subjected to RT training for 30 days; the other PAH and healthy rats (n = 8/group) did not exercise. PAH rats had lower reproductive organ weight, serum testosterone levels, testicular glucose, and nitric oxide (NO) levels, Leydig cell parameters, tubular morphometry, germ cell counts, and daily sperm production than healthy animals did. The practice of RT attenuated the negative impact of PAH on the relative weights of the testes and epididymides, Leydig cell number, nuclear volume, testicular NO levels, and seminiferous epithelium architecture. Moreover, RT positively influenced testosterone levels in PAH animals. We conclude that PAH exerts deleterious effects on testicular histology and function. However, RT can be beneficial to the PAH-affected testicular parameters.
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Hipertensión Arterial Pulmonar , Entrenamiento de Fuerza , Masculino , Ratas , Animales , Humanos , Ratas Wistar , Testículo , Semen , TestosteronaRESUMEN
AIM: We tested the effects of low- to moderate-intensity resistance exercise training (RT) on the structure and function of pulmonary, right ventricle (RV), and skeletal muscle tissues in rats with stable pulmonary artery hypertension (PAH). MAIN METHODS: After the first monocrotaline (MCT; 20 mg/kg) injection, male rats were submitted to a RT program (Ladder climbing; 55-65 % intensity), 5 times/week. Seven days later rats received the second MCT dose. Physical effort tolerance test and echocardiographic examination were performed. After euthanasia, lung, heart, and biceps brachii were processed for histological, single myocyte, and biochemical analysis. KEY FINDINGS: RT improved survival and physical effort tolerance (i.e., maximum carrying load), mitigated the pulmonary artery resistance increase (i.e., TA/TE), and preserved cardiac function (i.e., fractional shortening, ejection fraction, stroke volume and TAPSE). RT counteracted oxidative stress (i.e., CAT, SOD, GST, MDA and NO) and adverse remodeling in lung (i.e., collapsed alveoli) and in biceps brachii (i.e., atrophy and total collagen) tissues. RT delayed RV adverse remodeling (i.e., hypertrophy, extracellular matrix, collagen types I and III, and fibrosis) and impairments in single RV myocyte contractility (i.e., amplitude and velocity to peak and relaxation). RT improved the expression of gene (i.e., miRNA 214) and intracellular Ca2+ cycling regulatory proteins (i.e., PLBser16); and of pathological (i.e., α/ß-MHC and Foxo3) and physiological (i.e., Akt, p-Akt, mTOR, p-mTOR, and Bcl-xL) hypertrophy pathways markers in RV tissue. SIGNIFICANCE: Low- to moderate-intensity RT benefits the structure and function of pulmonary, RV, and skeletal muscle tissues in rats with stable pulmonary artery hypertension.
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Resumo Fundamento A hipertrofia e a dilatação do ventrículo direito observadas na hipertensão arterial pulmonar (HAP) prejudicam a dinâmica do ventrículo esquerdo (VE) achatando o septo interventricular. Objetivo Investigar se o treinamento físico resistido (TFR) de intensidade baixa a moderada é benéfico para funções contráteis do VE e de cardiomiócitos em ratos durante o desenvolvimento de HAP induzida por monocrotalina (MCT). Métodos Foram usados ratos Wistar machos (Peso corporal: ~ 200 g). Para avaliar o tempo até o possível surgimento de insuficiência cardíaca (ou seja, ponto de desfecho), os ratos foram divididos em dois grupos, hipertensão com sedentarismo até a insuficiência (HSI, n=6) e hipertensão com treinamento até a insuficiência (HTI, n=6). Para testar os efeitos do TFR, os ratos foram divididos entre grupos de controle sedentários (CS, n=7), hipertensão com sedentarismo (HS, n=7) e hipertensão com treinamento (HT, n=7). A HAP foi induzida por duas injeções de MCT (20 mg/kg, com um intervalo de 7 dias). Os grupos com treinamento foram submetidos a um protocolo de TFR (subir escadas; 55-65% da máxima carga carregada), 5 dias por semana. A significância estatística foi definida em p <0,05. Resultados O TFR prolongou o ponto de desfecho (~25%), melhorou a tolerância ao esforço físico (~55%) e atenuou as disfunções de contratilidade de VE e de cardiomiócitos promovidas pela MCT preservando a fração de ejeção e o encurtamento fracional, a amplitude do encurtamento, e as velocidades de contração e relaxamento nos cardiomiócitos. O TFR também preveniu os aumentos de fibrose e colágeno tipo I no ventrículo esquerdo causados pela MCT, além de manter as dimensões de miócitos e colágeno tipo III reduzidas por MCT. Conclusão O TFR de intensidade baixa a moderada é benéfico para funções contráteis de VE e cardiomiócitos em ratos durante o desenvolvimento de HAP induzida por MCT.
Abstract Background The right ventricular hypertrophy and dilation observed in pulmonary artery hypertension (PAH) damages the left ventricle (LV) dynamics by flattening the interventricular septum. Objective To investigate whether low- to moderate-intensity resistance exercise training (RT) is beneficial to LV and cardiomyocyte contractile functions in rats during the development of monocrotaline (MCT)-induced PAH. Methods Male Wistar rats (Body weight: ~ 200 g) were used. To assess the time to potential heart failure onset (i.e., end point), rats were divided into sedentary hypertension until failure (SHF, n=6) and exercise hypertension until failure (EHF, n=6) groups. To test RT effects, rats were divided into sedentary control (SC, n = 7), sedentary hypertension (SH, n=7), and exercise hypertension (EH, n=7) groups. PAH was induced by two MCT injections (20 mg/kg, with 7 days interval). Exercise groups were submitted to an RT protocol (Ladder climbing; 55-65% of carrying maximal load), 5 times/week. Statistical significance was assumed at P < 0.05. Results RT prolonged the end point (~25 %), enhanced the physical effort tolerance (~ 55%), and mitigated the LV and cardiomyocyte contractility dysfunctions promoted by MCT by preserving the ejection fraction and fractional shortening, the amplitude of shortening, and the velocities of contraction and relaxation in cardiomyocytes. RT also prevented increases in left ventricle fibrosis and type I collagen caused by MCT, and maintained the type III collagen and myocyte dimensions reduced by MCT. Conclusion Low- to moderate-intensity RT benefits LV and cardiomyocyte contractile functions in rats during the development of MCT-induced PAH.
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BACKGROUND: The right ventricular hypertrophy and dilation observed in pulmonary artery hypertension (PAH) damages the left ventricle (LV) dynamics by flattening the interventricular septum. OBJECTIVE: To investigate whether low- to moderate-intensity resistance exercise training (RT) is beneficial to LV and cardiomyocyte contractile functions in rats during the development of monocrotaline (MCT)-induced PAH. METHODS: Male Wistar rats (Body weight: ~ 200 g) were used. To assess the time to potential heart failure onset (i.e., end point), rats were divided into sedentary hypertension until failure (SHF, n=6) and exercise hypertension until failure (EHF, n=6) groups. To test RT effects, rats were divided into sedentary control (SC, n = 7), sedentary hypertension (SH, n=7), and exercise hypertension (EH, n=7) groups. PAH was induced by two MCT injections (20 mg/kg, with 7 days interval). Exercise groups were submitted to an RT protocol (Ladder climbing; 55-65% of carrying maximal load), 5 times/week. Statistical significance was assumed at P < 0.05. RESULTS: RT prolonged the end point (~25 %), enhanced the physical effort tolerance (~ 55%), and mitigated the LV and cardiomyocyte contractility dysfunctions promoted by MCT by preserving the ejection fraction and fractional shortening, the amplitude of shortening, and the velocities of contraction and relaxation in cardiomyocytes. RT also prevented increases in left ventricle fibrosis and type I collagen caused by MCT, and maintained the type III collagen and myocyte dimensions reduced by MCT. CONCLUSION: Low- to moderate-intensity RT benefits LV and cardiomyocyte contractile functions in rats during the development of MCT-induced PAH.
FUNDAMENTO: A hipertrofia e a dilatação do ventrículo direito observadas na hipertensão arterial pulmonar (HAP) prejudicam a dinâmica do ventrículo esquerdo (VE) achatando o septo interventricular. OBJETIVO: Investigar se o treinamento físico resistido (TFR) de intensidade baixa a moderada é benéfico para funções contráteis do VE e de cardiomiócitos em ratos durante o desenvolvimento de HAP induzida por monocrotalina (MCT). MÉTODOS: Foram usados ratos Wistar machos (Peso corporal: ~ 200 g). Para avaliar o tempo até o possível surgimento de insuficiência cardíaca (ou seja, ponto de desfecho), os ratos foram divididos em dois grupos, hipertensão com sedentarismo até a insuficiência (HSI, n=6) e hipertensão com treinamento até a insuficiência (HTI, n=6). Para testar os efeitos do TFR, os ratos foram divididos entre grupos de controle sedentários (CS, n=7), hipertensão com sedentarismo (HS, n=7) e hipertensão com treinamento (HT, n=7). A HAP foi induzida por duas injeções de MCT (20 mg/kg, com um intervalo de 7 dias). Os grupos com treinamento foram submetidos a um protocolo de TFR (subir escadas; 55-65% da máxima carga carregada), 5 dias por semana. A significância estatística foi definida em p <0,05. RESULTADOS: O TFR prolongou o ponto de desfecho (~25%), melhorou a tolerância ao esforço físico (~55%) e atenuou as disfunções de contratilidade de VE e de cardiomiócitos promovidas pela MCT preservando a fração de ejeção e o encurtamento fracional, a amplitude do encurtamento, e as velocidades de contração e relaxamento nos cardiomiócitos. O TFR também preveniu os aumentos de fibrose e colágeno tipo I no ventrículo esquerdo causados pela MCT, além de manter as dimensões de miócitos e colágeno tipo III reduzidas por MCT. CONCLUSÃO: O TFR de intensidade baixa a moderada é benéfico para funções contráteis de VE e cardiomiócitos em ratos durante o desenvolvimento de HAP induzida por MCT.
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Hipertensión Pulmonar , Condicionamiento Físico Animal , Disfunción Ventricular Izquierda , Animales , Masculino , Ratas , Colágeno Tipo I , Colágeno Tipo III , Modelos Animales de Enfermedad , Hipertensión Pulmonar/inducido químicamente , Hipertensión Pulmonar/terapia , Monocrotalina/efectos adversos , Arteria Pulmonar , Ratas Wistar , Entrenamiento de FuerzaRESUMEN
Mesenchymal stromal cells (MSCs) have long been used in research for bone regeneration, with evidence of their beneficial properties. In the segmental area of MSC-based therapies, MSC-derived extracellular vesicles (EVs) have also shown great therapeutic effects in several diseases, including bone healing. This study aimed to assess whether the conditioning of MSCs improves the therapeutic effects of their derived extracellular vesicles for bone regeneration. Electronic research was performed until February 2021 to recover the studies in the following databases: PubMed, Scopus, and Web of Science. The studies were screened based on the inclusion criteria. Relevant information was extracted, including in vitro and in vivo experiments, and the animal studies were evaluated for risk of bias by the SYRCLE tool. A total of 463 studies were retrieved, and 18 studies met the inclusion criteria (10 studies for their in vitro analysis, and 8 studies for their in vitro and in vivo analysis). The conditioning methods reported included: osteogenic medium; dimethyloxalylglycine; dexamethasone; strontium-substituted calcium silicate; hypoxia; 3D mechanical microenvironment; and the overexpression of miR-375, bone morphogenetic protein-2, and mutant hypoxia-inducible factor-1α. The conditioning methods of MSCs in the reported studies generate exosomes able to significantly promote bone regeneration. However, heterogeneity regarding cell source, conditioning method, EV isolation and concentration, and defect model was observed among the studies. The different conditioning methods reported in this review do improve the therapeutic effects of MSC-derived EVs for bone regeneration, but they still need to be addressed in larger animal models for further clinical application.
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Doppler ultrasonography is used in the evaluation of hemodynamics, and the resistivity (RI) and pulsatility (PI) indexes provide information about resistance to blood flow within a vessel. This systematic review was carried out to evaluate renal RI and PI in clinically healthy and nonsedated cats and as well as their usefulness in the evaluation of kidney disease in cats. An electronic search in the PubMed, Scopus, and Web of Science databases was carried out using the terms "resistive index" or "resistivity index" or "pulsatility index;" "Doppler;" "renal" or "kidney;" and "cat" or "feline" in titles, abstracts, and keywords. Variables of interest related to experimental model features, research methods, and technical resources were extracted from the studies. The methodological quality was assessed with SYRCLE's risk of bias tool. Thus, 14 studies involving healthy and sick cats were selected. Interestingly, the upper limits estimated for both RI and PI varied among studies. The upper limits of renal RI for healthy cats varied between 0.64 and 0.72, while for PI, the values varied from 1.06 to 1.29. A limited number of studies evaluated cats with kidney disease. In most studies, RI values of kidneys with different conditions were significantly different from kidneys of healthy animals, indicating that RI values increase with kidney disease. The parameters body weight, heart rate, and age seem to influence the RI values. Standardized studies regarding its realization and description are still necessary to define normal values and analyze its applicability in the clinical diagnostic routine.
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Enfermedades de los Gatos , Enfermedades Renales , Animales , Enfermedades de los Gatos/diagnóstico por imagen , Gatos , Riñón/diagnóstico por imagen , Enfermedades Renales/veterinaria , Arteria Renal/diagnóstico por imagen , Arteria Renal/fisiología , Ultrasonografía DopplerRESUMEN
Abstract Background: There are divergences in the literature regarding the experimental model (Wistar-WIS or Wistar Kyoto-WKY) to be used as a Spontaneously Hypertensive Rat (SHR) control. The characterization of these models in terms of cardiovascular parameters provides researchers with important tools at the time of selection and application in scientific research. Objective: The aim of this study was to evaluate the use of WIS and WKY as a Spontaneously Hypertensive Rat (SHR) control by assessing the long-term behavior of blood pressure and cardiac structure and function in these strains. Methods: To this end, WIS, WKY, and SHR underwent longitudinal experiments. Blood pressure and body mass were measured every two weeks from the 8th to the 72nd. Echocardiographic analysis was performed in all groups with 16, 48, and 72 weeks of life. After having applied the normality test, the Two-Way ANOVA of repeated measures followed by the Tukey post hoc test was used. A significance level of 5% was established. Results: The WIS group showed higher body mass (p<0.05), while the WKY and SHR presented higher body mass variation over time (p<0.05). SHR exhibited increased values of systolic, diastolic, and mean blood pressure when compared to WKY and WIS, whereas the WKY generally showed higher values than WIS (p<0.05). Regarding the cardiac function, SHR showed reduced values, while the WKY presented an early decrease when compared to WIS with aging (p<0.05). Conclusion: WIS is a more suitable normotensive control for SHR than WKY in experiments to test blood pressure and cardiac structure and function.
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Animales , Masculino , Ratas , Presión Arterial/fisiología , Corazón/anatomía & histología , Corazón/fisiología , Hipertensión/fisiopatología , Ratas Endogámicas SHR , Ratas Endogámicas WKY , Peso Corporal , Ecocardiografía , Estudios Longitudinales , Ratas Wistar , Modelos Animales de EnfermedadRESUMEN
This study evaluated the effect of aerobic exercise training (AET) and supplementation with açai on cardiac structure and function in rats submitted to a high-fat diet. Two-month old Fischer male rats were divided into 5 groups: Control (C), High-fat Diet (H), High-fat Diet + Açai (HA), High-fat Diet + AET (HT), High-fat Diet + Açai + AET (HAT). The high-fat diet had 21.8% lard and 1% cholesterol (H and HT), or supplemented with 1% lyophilized açai pulp (HA and HAT). The HT and HAT groups performed AET on a treadmill (5 days/week, 1 h/day, 60% of the maximum running speed) for 8 weeks. Exercise tolerance test were performed, and adiposity index calculated. After euthanasia, the left ventricle (LV) was dissected and processed for histological, single myocyte intracellular calcium ([Ca2+]i) transient and contractility, oxidative stress and gene expression analysis. AET improved running capacity and reduced the adiposity index. Both AET and açai supplementation inhibited the increase in the LV collagen content, the deleterious effects on the [Ca2+]i transient and contractility in cardiomyocytes and the increment in oxidative stress, caused by the consumption of a high-fat diet. Aerobic exercise training and açai supplementation can mitigate damage caused by high-fat diet in cardiac structure and function, though the combination of treatments had no additional effects.
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Dieta Alta en Grasa , Suplementos Dietéticos , Animales , Dieta Alta en Grasa/efectos adversos , Ejercicio Físico , Masculino , Estrés Oxidativo , Ratas , Ratas Endogámicas F344RESUMEN
There are numerous sources of multipotent mesenchymal stromal cells (MSC) with therapeutic potential, and bone marrow is the main one. However, pain, lack of donors and comorbidities associated with harvesting stimulate the search for new sources of MSCs. The aim of this work is to obtain cells from umbilical cord (UC) perivascular tissue of dogs and characterize them as MSCs. For this, the UC was obtained from therapeutic cesarean sections and submitted to enzymatic digestion. The obtained cells were subjected to growth and proliferation tests, as well as the analysis of surface markers, differentiation test in three mesenchymal lineages and analysis of differentiation markers expression. From all the UC used in this study an adherent with fibroblastoid shape cell was obtained, with an initial number of 4.8â¯×â¯105 of cells. The growth curves showed a lag phase from 0 to 24â¯h, followed by a phase of growth of 24 to 168â¯h, and then phase of cell decay. The doubling time was kept around 15â¯h until the sixth passage, from which there were signs of cellular senescence. The differentiation assays demonstrated the ability of cells to differentiate into osteoblasts, adipocytes and chondrocytes when subjected to the induction mediums. The study of surface markers was positive for adhesion markers and negative for hematopoietic markers. Thus, cells obtained from canine UC perivascular tissue by enzymatic digestion are multipotent MSC and the protocol developed ensures the perivascular origin of these cells.
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Células Madre Mesenquimatosas , Cordón Umbilical/irrigación sanguínea , Cordón Umbilical/citología , Animales , Proliferación Celular , Células Cultivadas , Perros , Femenino , Humanos , EmbarazoRESUMEN
Feline chronic gingivostomatitis (FCGS) is an oral inflammatory condition that frequently affects felines. Its etiology is not well defined, but several viral agents are thought to be involved. Several therapeutic protocols have been described, yet treatment response is often variable, and the therapeutic success is transient with an unpredictable duration. Therefore, the therapeutic strategy needs to be tailored for each patient. This work relates a case characterized by viral involvement in its etiopathogenesis providing an alternative to the most widely-used methods that so often frustrate both veterinary doctors and pet owners.(AU)
A gengivostomatite crônica felina (FCGS) é uma condição inflamatória oral que frequentemente afeta felinos. A sua etiologia não está bem definida, mas acredita-se que vários agentes virais possam estar envolvidos. Muitos protocolos terapêuticos têm sido descritos, no entanto, a resposta ao tratamento é frequentemente variável e o sucesso terapêutico é transitório com uma duração imprevisível. Portanto, a estratégia terapêutica precisa ser adaptada para cada paciente. O presente trabalho propõe a caracterização do envolvimento viral na etiopatogenia da doença como uma alternativa aos métodos mais amplamente utilizados, que muitas vezes frustram médicos veterinários e os donos de animais de estimação.(AU)
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Animales , Gatos , Estomatitis Herpética/veterinaria , Gatos/anomalías , Calicivirus Felino/clasificaciónRESUMEN
The study aimed to evaluate biocompatibility, osteoconduction and osseointegration of a pasty composite of hydroxyapatite (20%) and lignin (80%) as a promoter of metal implant and bone tissue integration. An intramedullary Schanz pin was implanted in both tibias of fifteen bitches. In the left tibia, the pin was coated with the biomaterial at the time of surgery. Marrow cavity was also filled with the biomaterial. Right limb did not receive the biomaterial, then constituting the control group. Tibias were harvested from five animals at 8, 60 and 150 days after surgery; three of them were analyzed by histological and biomechanical assessment and the two remaining tibias by X-ray diffraction. Results showed that the biomaterial is biocompatible, with osteoconductivity and osseointegration properties. Histological analysis and diffractograms showed the presence of hydroxyapatite in samples in all periods, although the presence of organic material of low crystallinity was variable. There was no statistical difference in the forces required for removal of the biocompatibility, osteoconductivity and osseointegration, it was not able to promote a better intramedullary pin anchorage.
O trabalho objetivou avaliar a biocompatibilidade, a osteocondução e a osseointegração de um compósito pastoso de hidroxiapatita (20%) e lignina (80%) como promotor de integração entre implante metálico e tecido ósseo. Um pino intramedular de Schanz foi implantado em ambas as tíbias de quinze cadelas. Na tíbia esquerda, o pino foi coberto com o biomaterial no momento da cirurgia. A cavidade medular também foi preenchida com o biomaterial. O membro direito não recebeu o biomaterial, constituindo assim o grupo controle. As tíbias foram coletadas de cinco animais aos oito, 60 e 150 dias após a cirurgia, sendo três encaminhadas para avaliação histológica e biomecânica e as duas restantes, para difração de raios X. Os resultados revelaram biocompatibilidade do material, com propriedades de osteocondução e osseointegração. As análises histológicas e os difratogramas mostraram presença da hidroxiapatita no tecido em todos os períodos avaliados, embora a presença de material orgânico de baixa cristalinidade tenha sido variável. Não houve diferença estatística na força necessária para remoção do pino intramedular entre os tempos ou tratamentos. Embora o biomaterial tenha apresentado biocompatibilidade, osteocondutividade e osseointegração, ele não foi capaz de promover uma melhor ancoragem do pino intramedular.
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OBJECTIVE: Absorbable membranes are used to promote the regeneration of periodontal defects by Guided Tissue Regeneration (GTR). However, their collapse into the defect is commonly reported, impairing regeneration. Therefore, absorbable but rigid membranes aiming at preventing such collapse were developed and analyzed in periodontal regeneration. MATERIALS AND METHODS: Membranes were analyzed in class II furcation defects in dogs; procedures included periodontal disease induction, prophylaxis and GTR (treated groups) or open flap debridement alone (control group). For GTR, the membranes were made of either 25% hydroxyapatite (HA) in polyhydroxybutyrate matrix (PHB) or 35% HA in PHB. Animals were clinically evaluated for gingival recession, clinical attachment level (CAL) and biopsies were collected at 60 and 120 days. Bone volume, trabeculae number, trabecular thickness and trabecular separation were quantified by micro-computed tomography, followed by histology. RESULTS: Membrane exposure was observed in both treated groups (25 and 35% HAP) from the 8(th) day after surgery, continuously progressing until 120 days. Mean CAL for all groups remained above normal values for dogs. Bone volumetric values were not significantly different. Partial formation of bone, cementum and periodontal ligament was observed in treated groups. An inflammatory infiltrate was observed in the dense connective tissue that partially filled the center of the treated defects with active osteoclasts on bone surface. CONCLUSION: Although partial regeneration of the defect was observed, it was limited by wound contamination. Consequently, rigid absorbable membranes made of HA and PHB failed to improve the regeneration of class II furcation defects in dogs.
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Materiales Biocompatibles , Modelos Animales de Enfermedad , Defectos de Furcación/cirugía , Regeneración Tisular Dirigida , Membranas Artificiales , Animales , PerrosRESUMEN
A doença periodontal pode ser definida como a condição inflamatória dos tecidos de suporte do dente em resposta ao acúmulo do biofilme. A consequencia é a formação de graves defeitos ósseos, devido à perda dos tecidos periodontais, levando, em última instância, à perda dos dentes, predisposição a fraturas de mandíbula e formação de comunicações oronasais. O principal tratamento é a prevenção, incluindo a escovação dentária diária e a profilaxia periodontal, procedimento realizado pelo médico veterinário para remoção do biofilme e cálculo dentário acumulados. A recuperação dos tecidos perdidos, ou seja, a regeneração periodontal, é um processo mais complexo, pois envolve a formação de três tecidos intimamente ligados: osso alveolar, ligamento periodontal e cemento. Assim, diversos materiais e técnicas foram e são constantemente desenvolvidos, incluindo membranas para regeneração tecidual guiada e a aplicação de enxertos e biomateriais, amplamente estudados na odontologia humana e já disponíveis para aplicação na rotina clínica veterinária. Adicionalmente, novas possibilidades surgem com a associação dessas técnicas a fatores de crescimento e células-tronco e o desenvolvimento das membranas multifuncionais.
Periodontal disease can be defined as the inflammatory condition of the tooth-supportive tissues as a response to biofilm accumulation. The consequence is the formation of severe bone defects due to the loss of periodontal tissues that ultimately lead to tooth loss, predispose to mandible fractures and formation of oronasal communications. The main treatment is prevention, including daily tooth brushing and periodontal prophylaxis, a procedure done by veterinaries to remove retained biofilm and calculus. Recovering lost tissues, i.e. periodontal regeneration, is a more complex process involving the formation of three tissues highly connected: alveolar bone, periodontal ligament and cementum. Therefore, several materials and techniques were and are constantly developed, including membranes for guided tissue regeneration and the application of bone grafts and biomaterials, widely studied in human dentistry and already available for veterinary practice. Additionally, new possibilities rise with the association of these techniques to growth factors and stem cells and the development of multifunctional membranes.
RESUMEN
In this work, biocompatibility, osteointegration, osteoconductivity, and biodegradation of a hydroxyapatite polyhydroxybutyrate new composite were evaluated. The composite was implanted in rabbits' bone defects and clinical, radiographic, histological, and histomorphometric data of these animals were compared with those of unfilled defects on the days 8th, 45th, and 90th after surgery. No significant differences existed between the groups for the evaluated clinical parameters. Radiographs showed bone-composite direct contact. Bone formed within the defect, interface and inside the composite. Significant differences were found between the bone and connective tissues percentage within the defect at all dates and at the interface on the 45th day, bone tissue prevailing. Composite's biodegradation signs were evident: giant cells on the surface of composite fragments separated from the original block in the absence of inflammatory infiltrate. These data supported that such composite was biocompatible, biodegradable, osteoconductive and integrate to bone.
A biocompatibilidade, osteointegração, osteocondução e biodegradação de um novo compósito de hidroxiapatita e polihidroxibutirato foram avaliados. O compósito foi implantado em defeitos ósseos em coelhos e dados clínicos, radiográficos, histológicos e histomorfométricos foram comparados aos de defeitos não preenchidos aos 8, 45 e 90 dias após a cirurgia. Não foram observadas diferenças significantes entre os grupos para os parâmetros clínicos avaliados. Contato direto entre osso e compósito foi observado nas radiografias. Tecido ósseo se formou dentro do defeito, interface e dentro do compósito. Foram observadas diferenças significativas entre a porcentagem dos tecidos ósseo e conjuntivo dentro do defeito em todas as datas de avaliação e na interface aos 45 dias, com predominância do tecido ósseo. Sinais de biodegradação foram observados: células gigantes na superfície de fragmentos do compósito separados do bloco original, na ausência de infiltrado inflamatório. Os dados permitem concluir que o compósito é biocompatível, biodegradável, osteocondutor e se integra ao tecido ósseo.