Biomechanical Effects of Angiotensin 1-7 in Diabetes Rats Femur / Efectos Biomecánicos de la Angiotensina 1-7 en el Fémur de Ratas Diabéticas

SUMMARY: It is known that diabetes mellitus has late complications, including microvascular and macrovascular diseases. Diabetes can affect bones through biochemical markers of bone structure, density, and turnover. This study aimed to biomechanically investigate the bone-protective effects of angiotensin 1-7 (Ang 1-7), one of the active peptides in the renin-angiotensin system, in rats with diabetes. Thirty male Wistar albino rats, three months old and weighing 250-300 g, were divided into four groups: diabetes, Ang 1- 7, diabetes plus Ang 1-7, and control. One month later, diabetes developed in rats; the rats were sacrificed, and their right femur was removed. Three-point bending biomechanical tests were performed on the femurs. The diabetic group had significantly higher bone fragility than the other groups (Pr >.05). Bone fragility was lower, and bone flexibility was higher in the Ang 1-7 groups (Pr>F value 0.05). As a result of our study, the effect of Ang 1-7 on the bones of rats with diabetes was investigated biomechanically. Ang 1-7 has a protective impact on the bones of rats with diabetes.

Se sabe que la diabetes mellitus tiene complicaciones tardías, incluyendo enfermedades microvasculares y macrovasculares. La diabetes puede afectar los huesos a través de los marcadores bioquímicos de la estructura, la densidad y el recambio óseo. Este estudio tuvo como objetivo investigar biomecánicamente los efectos protectores en los huesos de la angiotensina 1-7 (Ang 1-7), uno de los péptidos activos en el sistema renina-angiotensina, en ratas con diabetes. Treinta ratas albinas Wistar macho, de tres meses de edad y con un peso de 250-300 g, se dividieron en cuatro grupos: diabetes, Ang 1-7, diabetes más Ang 1-7 y control. Un mes después, se desarrolló diabetes en ratas; se sacrificaron los animales y se extrajo su fémur derecho. Se realizaron pruebas biomecánicas de flexión de tres puntos en los fémures. El grupo diabéticos tenía una fragilidad ósea significativamente mayor que los otros grupos (Pr > 0,05). La fragilidad ósea fue menor y la flexibilidad ósea fue mayor en los grupos Ang 1-7 (valor Pr>F 0,05). Como resultado de nuestro estudio, se determinó biomecánicamente el efecto de Ang 1-7 en los huesos de ratas con diabetes. Se concluye que Ang 1-7 tiene un impacto protector en los huesos de ratas diabéticas.

Effect of growth hormone (GH) and resistance training on the collagen properties of femoral bone tissue / Efecto de la hormona de crecimiento (HC) y el entrenamiento de fuerza en las propiedades colágenas del tejido óseo femoral

The indiscriminate use of anabolic steroids in gyms has been growing in a generalized way, among which, the most common is growth hormone (GH). In the short term GH may potentiate muscle growth, especially when taken in combination with resistance training. However, the effects of this hormone are not yet fully understood in the literature, especially in relation to collagen properties. The objective of this study was to evaluate the effect of the application of growth hormone (GH) and resistance training (RT) on the collagen properties of femoral bone tissue using Raman Spectroscopy. In this study 40 male rats were randomly distributed into four groups (n=10): control (C), control and GH application (GH), resistance training (T), and resistance training and GH application (GHT). The training consisted of four series of 10 water jumps, performed three times a week, with an overload corresponding to 50 % of body weight and duration of four weeks. GH was applied at a dosage of 0.2 IU/Kg (0.067 mg/kg) to each animal, three times a week, every other day. The animals were euthanized and the right femurs were collected for analysis of bone structure. Raman spectroscopy (RS) was used to observe the following compounds from their respective bands: type I collagen (662 cm-1), amide III (1243 cm-1), proteins including type I collagen (1278 cm-1), woven collagen (1322 cm-1), association of collagen, phospholipids, nucleic acid, and phosphate (1330 cm-1), and collagen and protein deformation (1448 cm-1). The results demonstrated an increase in the collagen properties in all analyzed variables, however, the T group presented a statistically significant difference (p<0.05). It is possible to conclude that isolated physical training was shown to be more efficient than when combined with the application of GH to increase the collagen properties of the femoral bone tissue.

El uso indiscriminado de anabolizantes en los gimnasios ha aumentado de forma generalizada, entre éstos la hormona de crecimiento (HC) es una de las más utilizadas, y a corto plazo puede potencializar el crecimiento muscular, principalmente cuando es realizado en combinación con el entrenamiento de fuerza. Sin embargo, los efectos de esta hormona aún no están totalmente esclarecidos en la literatura, especialmente en relación a las propiedades colágenas. El objetivo del estudio fue evaluar el efecto de la aplicación del HC y entrenamiento de fuerza (E) en las propiedades colágenas del tejido óseo femoral a partir de la utilización de la espectroscopía Raman. Se usaron 40 ratas Wistar distribuidos en cuatro grupos (n=10): control (C), control y aplicación del HC (HCC), entrenamiento de fuerza (E) y entrenamiento de fuerza y aplicación del HC (THC). El entrenamiento fue compuesto por cuatro series de 10 saltos acuáticos, realizados tres veces por semana, con sobrecarga correspondiente a 50 % del peso corporal y duración de cuatro semanas. El HC fue aplicado en una dosificación de 0,2 UI/Kg (0,067 mg/kg) en cada animal, tres veces por semana, en días no consecutivos. Los animales fueran eutanasiados y se retiró el fémur derecho para realización del análisis de la estructura ósea. La espectroscopía Raman (ER) fue utilizada para observar los siguientes compuestos a partir de las respectivas bandas: colágeno tipo I (662 cm-1), amida III (1243 cm1), proteínas, incluido colágeno tipo I (1278 cm-1), colágeno retorcido (1322 cm-1), asociación de colágeno, fosfolípidos, ácidos nucleicos y fosfato (1330 cm-1), deformación de colágeno y proteína (1448 cm-1). Hubo aumento en las propiedades colágenas en todas las variables analizadas, sin embargo, solamente el grupo E demostró una diferencia estadísticamente significativa (p<0,05). En conclusión, para el aumento de las propiedades colágenas del tejido óseo femoral, el entrenamiento físico aislado es más eficiente que el entrenamiento combinado con el uso de HC.

La proloterapia mostró buenos resultados para aliviar el dolor de pacientes con síndrome de disfunción músculo tendinosa del trocánter mayor: cohorte prospectiva / Prolotherapy showed good results to relieve pain of patients with tendon-muscle dysfunction syndrome of the greater trochanter: prospective case series

OBJETIVOS: Describir la evolución de una cohorte de pacientes con sindrome de disfunción dolorosa del trocánter mayor tratados con proloterapia. MÉTODOS: 30 pacientes con dolor crónico recibieron una mediana de 3,5 inyecciones de dextrosa al 12,5% y lidocaina al 0,5% en la entesis de los músculos que se insertan en el trocanter mayor. Fueron evaluados sus cambios en el dolor mediante una escala analógica visual (EAV) y en la calidad de vida, a través del puntaje Euro Quol 5D. RESULTADOS: A los seis meses de la primera inyección se constató una reducción media del dolor de 5,45 (IC 95% 4,55 a 6,34) puntos de la EAV, desde una media basal de 8,01 (5 a 10) a una media a los seis meses de 2,56 (1 a 7); y una mejoría de la calidad de vida desde 0,401 a 0,891 puntos en la escala Euro Quol 5D. No se observaron efectos adversos. CONCLUSIÓN: Los pacientes con sindrome de disfunción dolorosa del trocánter mayor tratados con proloterapia evolucionaron con una reducción en su nivel de dolor y una mejoría en su calidad (AU)

OBJECTIVES: To describe the evolution of a cohort of patients with a major trochanter dysfunction pain syndrome treated with prolotherapy. METHODS: 30 patients with chronic pain received a median of 3.5 injections of 12.5% dextrose and 0.5% lidocaine in the entesis of the muscles that are inserted into the greater trocanter. Their changes in pain were assessed using a visual analogue scale (VAS) and quality of life, through the Euro Quol 5D score. RESULTS: Six months after the first injection, a mean pain reduction of 5.45 (95% CI 4.55 to 6.34) VAS points was observed, from a baseline average of 8.01 (5 to 10 ) to an average of 2.56 (1 to 7) at six-month; and an improvement in the quality of life from 0.401 to 0.891 points on the Euro Quol 5D scale. No adverse effects were observed. CONCLUSION: Patients with major trochanter dysfunction pain syndrome treated with prolotherapy evolved with a reduction in their level of pain and an improvement in their quality of life (AU)

Inhibitory effect of Astragalus polysaccharide on osteoporosis in ovariectomized rats by regulating FoxO3a /Wnt signaling pathway

Abstract Purpose: To investigate inhibitory effect of Astragalus polysaccharide (APS) on osteoporosis in ovariectomized rats by regulating FoxO3a/Wnt2 signaling pathway. Methods: Postmenopausal osteoporosis (PMOP) animal model was developed by excising the bilateral ovaries of rats. The model rats were administered with APS (200 mg/kg, 400 mg/kg, 800 mg/kg) by intragastric administration once daily for 12 weeks. Bone density, bone metabolism index and oxidative stress index were measured in all groups. Furthermore, the regulation of APS of FoxO3a / Wnt2 signaling pathway was observed. Results: APS has an estrogen-like effect, which can increase bone mass, lower serum ALP and BGP values, increase blood calcium content, and increase bone density of the femur and vertebrae in rats. At the same time, APS can increase the bone mineral content of the femur, increase the maximum stress, maximum load and elastic modulus of the ovariectomized rats, improve oxidative stress in rats by increasing the gene expression of β-catenin and Wnt2 mRNA and inhibiting the gene expression of FoxO3a mRNA. Conclusion: Astragalus polysaccharide can effectively alleviate oxidative stress-mediated osteoporosis in ovariectomized rats, which may be related to its regulation of FoxO3a/Wnt2/β-catenin pathway.

Efectos del ranelato de estroncio sobre la densidad mineral ósea en hombres / Effect of strontium ranelate on bone mineral density in men

La osteoporosis afecta al 6-7% de la poblaciónmasculina. Es alta la proporción de pacientes confractura osteoporótica sin diagnóstico previo de estaenfermedad. La mortalidad luego de una fracturaes mayor en hombres que en población femenina;a pesar de esto, la mayoría de los pacientes no reciben tratamiento. Los fármacos aprobados, en nuestro medio, para tratar la osteoporosis masculina son:bifosfonatos, teriparatida y ranelato de estroncio. Elobjetivo de este estudio fue evaluar el efecto del ranelato de estroncio sobre la densidad mineral ósea enhombres después de 1 año de tratamiento. Se incluyeron los registros de 20 hombres de 67.8±3.0 años,tratados con ranelato de estroncio (2 g/día) durante 1año. Todos los pacientes presentaban un T-score inferior a -2.5 en cadera o columna vertebral o un T-scoreinferior a -2.0 y factores de riesgo de fractura. Nohubo modificación de parámetros de laboratorio luego del tratamiento (calcemia, calciuria, fósforo sérico,parathormona, 25(OH)vitamina D, fosfatasa alcalinay desoxipiridinolina). Luego de 1 año de tratamiento con ranelato de estroncio se observó incrementode la densidad mineral ósea en columna lumbar:0.953±0.029 versus 0.997±0.030 g/cm2 (p=0.0068),cuello femoral: 0.734±0.013 versus 0.764±0.016 g/cm2 (p=0.0084) y cadera total: 0.821±0.02 versus0.834±0.02 g/cm2 (p=0.0419). Conclusión: luego de1 año de tratamiento el ranelato de estroncio produjoun incremento significativo de la densidad mineralósea en columna lumbar y fémur proximal en hombres con osteoporosis (AU)

Osteoporosis affects 6-7% of the male population. The proportion of patients with fragility fractures but without diagnosis of the disease is high. Mortality after hip fracture is higherin men than in women; in spite of this, mostpatients are left without treatment for osteoporosis. Drugs approved, for the treatment ofosteoporosis in our country are bisphosphonates, teriparatide, and strontium ranelate (SrR).The objective of this study was to evaluate theeffect of SrR on axial BMD in men after one yearof treatment. We obtained pertinent data frommedical registries of 20 men aged 67,8±3,0 years,treated with oral SrR (2 g/day) for 12 months. All patients had a T-score below -2,5 at the hipor the lumbar spine, or a T-score below -2,0and one or more risk factors for fracture. Thelevels of serum calcium, phosphate, alkalinephosphatase, 25-hydroxyvitamin D, or PTH,or urinary calcium and desoxipyridinoline remained unchanged following SrR administration. After treatment with SrR there weresignificant increases in BMD at the lumbarspine: 0,953±0,029 versus 0,997±0,030 g/cm2(p=0,0068), femoral neck: 0,734±0,013 versus 0,764±0,016 g/cm2 (p=0.0084), and total hip: 0,821±0,02 versus 0,834±0,02 g/cm2(p=0,0419). Conclusion: in osteoporotic men,treatment with SrR significantly increases BMDin the lumbar spine and the proximal femur (AU)

Zoledronic acid effect on bone of growing rats / Efecto del ácido zoledrónico en el hueso de ratas en crecimiento

Zoledronic acid (ZA) is an antiresorptive drug used in children with bone diseases like osteogenesis imperfecta, juvenil osteoporosis, fibrous dysplasia and primary bone tumors. The aim of the present study was to evaluate the effects of ZA dose accumulation on growing bone during different periods of treatment in normal rats. Methods: A 4x2 factorial design was used to study the effect of the dose of ZA (D: 0-2.5-12.5-25 µg Z/kg body weight/s.c. weekly) and the length of treatment (T: 15-30 days) in normal female Sprague Dawley rats. Bone morphometric, histomorphometric, densitometric and biomechanical studies were performed. Results: Femoral length and cross-sectional area were affected by both D and T. A significant interaction between D and T was observed in length with a lower value at higher dose and 30 days of treatment. Growth plate of the tibia showed a decrease in total thickness with D and T. Histomorphometric and connectivity parameters of trabecular bone were significantly increased with D and several parameters were also affected by T. Cortical bone strength was increased only with T. Biomechanical parameters of trabecular bone showed significant interaction with greater effect at higher D and T. Conclusion: Even though a mild negative effect of the highest dose of ZA on linear and appositional growth was observed, the other bone parameters evaluated were improved. A careful risk/benefit analysis would lead us to conclude that the mild deleterious effects of ZA during growth are outweighed by the benefit obtained with treatment. (AU)

El ácido zoledrónico (AZ) es un fármaco antirresortivo utilizado en niños con enfermedades óseas como osteogénesis imperfecta, osteoporosis juvenil, displasia fibrosa y tumores óseos primarios. El objetivo del presente estudio fue evaluar los efectos de las dosis acumuladas de AZ en el hueso en crecimiento de ratas hembras normales durante diferentes períodos de tratamiento. Métodos: se utilizó un diseño factorial de 4x2 para estudiar el efecto de la dosis de AZ (D: 0-2,5-12,5-25 µg Z / kg de peso corporal /sc semanalmente) y el período de tratamiento (T: 15-30 días) en ratas Sprague Dawley. Se realizaron estudios óseos morfométricos, histomorfométricos, densitométricos y biomecánicos. Resultados: la longitud y el área de sección transversal del fémur se vieron afectadas tanto por D como por T. Se observó una interacción significativa entre D y T en la longitud obteniéndose un valor más bajo a la dosis más alta y a 30 días de tratamiento. El cartílago de crecimiento de la tibia mostró una disminución en el espesor total con D y T. Los parámetros histomorfométricos y de conectividad del hueso trabecular aumentaron significativamente con D y varios parámetros también se vieron afectados por T. La fortaleza ósea cortical aumentó solo con T. Los parámetros biomecánicos del hueso trabecular mostraron una interacción significativa con un mayor efecto a mayor D y T. Conclusión: a pesar que se observó un leve efecto negativo de la dosis más alta de AZ sobre el crecimiento lineal y aposicional, el resto de los parámetros óseos evaluados mejoraron. Un análisis cuidadoso del riesgo /beneficio permite concluir que los efectos negativos leves del AZ durante el crecimiento son superados por el beneficio obtenido con el tratamiento. (AU)

Effects of continual intermittent administration of parathyroid hormone on implant stability in the presence of osteoporosis: an in vivo study using resonance frequency analysis in a rabbit model

Abstract Objective: This study aimed to evaluate the effects of continual intermittent administration of parathyroid hormone (PTH) on implant stability in the presence of osteoporosis, using rabbit models. Material and Methods: Fifteen female New Zealand white rabbits underwent ovariectomy and were administered glucocorticoids to induce osteoporosis, following which they were divided into three groups. The first group received intermittent subcutaneous PTH for 4 weeks until implant placement (PTH1), while the second and third groups received PTH (PTH2) and saline (control), respectively, for 4 weeks before and after implant placement. After intermittent administration of PTH or saline, titanium implants were inserted into the left femoral epiphyses of all animals, and the implant stability quotient (ISQ) was measured immediately after placement to assess the primary stability and at 2 and 4 weeks after implant placement to assess osseointegration. At 4 weeks after implant placement, histological and histomorphometric evaluations were conducted and the bone area around the implant socket was measured as a ratio of the total bone area to the total tissue area. Results: Regarding primary stability, the ISQ values for the PTH1 and PTH2 groups were significantly higher than those for the control group (p<0.05). Concerning osseointegration, the ISQ values at 2 and 4 weeks were significantly higher for the PTH2 group than for the PTH1 and control (p<0.05) groups. Histological assessments showed a thicker and more trabecular bone around the implant sockets in the PTH2 specimens than in the PTH1 and control specimens. The bone area around the implant socket was significantly greater in the PTH2 group than in the PTH1 and control groups (p<0.05). Conclusions: Our results suggest that continual intermittent PTH administration before and after dental implant placement is effective for the achievement of favorable stability and osseointegration in the presence of osteoporosis.

Efeito da terapia de longa duração com ácido zoledrônico no osso esponjoso da mandíbula e fêmur de ratos Wistar / Effect of long-term zoledronic acid treatment on cancellous bone in the mandible and femur of Wistar rats

Os bisfosfonatos (BF) são amplamente utilizados no tratamento de doenças osteolíticas como metástases ósseas e osteoporose. A osteonecrose dos maxilares associada ao uso de BF (OMAB) é caracterizada pela presença de osso exposto ou que pode ser sondado através de uma fístula que persiste por mais de oito semanas em pacientes com história de terapia de BF e sem história de radioterapia na região de cabeça e pescoço e/ou sem doença metastática nos maxilares. A incidência de OMAB aumenta com a potência, duração do tratamento e dose de BF recebida. Até o presente momento, a fisiopatologia da OMAB não está clara, dificultando a prevenção e o tratamento. O objetivo deste estudo foi avaliar o efeito da administração de altas doses Ácido Zoledrônico (AZ) por período prolongado no osso esponjoso da mandíbula e da metáfise proximal do fêmur de ratos Wistar. Para relacionar as descobertas à fisiopatologia da OMAB, o regime de administração de BF de um modelo animal relevante desta lesão foi reproduzido. Seis animais receberam AZ (0,6 mg / kg) e seis receberam solução salina no mesmo volume (Controles). Os compostos foram administrados por via intraperitoneal em cinco doses a cada 28 dias. A eutanásia dos animais ocorreu após 150 dias de início da terapia. As hemimandíbulas e fêmures direitos foram escaneados usando Micro-tomografia computadorizada (Micro-CT) de alta resolução (14 m). Para a primeira análise realizada neste estudo, os dados morfométricos do osso esponjoso foram calculados na região do segundo e primeiro molar na mandíbula e na metáfise do fêmur usando CTAnalyzer (Bruker, Bélgica). Para a segunda análise, cinco amostras de hemimandíbulas de cada grupo foram cortadas em lâminas histológicas (5 m) e coradas com Hematoxilina e Eosina. Para comparar os parâmetros morfométricos na Micro-CT e histologia, as imagens de Micro-CT foram espacialmente alinhadas à histologia. Os dados morfométricos do osso alveolar foram calculados usando o software CTAnalyzer (Bruker, Bélgica) na região entre as raízes mesial e distal do primeiro molar. A densidade da área vascular (área vascular/área total; VA/TA) e os dados histomorfométricos ósseos foram estimados usando Axiovision na mesma região (entre as raízes mesial e distal do primeiro molar). Foi adotada significância estatística de 5% ( = 0,05). Os animais tratados com AZ apresentaram aumento significativo na porcentagem de volume ósseo (p <0,05) com trabéculas mais espessas, osso mais compacto com menor separação trabecular na mandíbula e no fêmur. Na mandíbula, o aumento da densidade óssea e diminuição da separação trabecular foram fortemente correlacionados com a diminuição da área vascular observada no grupo AZ (p <0,05). Em conclusão, o tratamento de longa duração com altas doses de AZ foi significativamente associado ao aumento na densidade óssea e à diminuição dos espaços medulares, canais nutritivos e vasculatura do osso alveolar. A análise com Micro-CT revelou alterações semelhantes na estrutura óssea tanto na mandíbula quanto no fêmur do grupo AZ.(AU)

Bisphosphonates (BFs) are widely used in the treatment of osteolytic diseases such as bone metastases and osteoporosis. The osteonecrosis of the jaws related to BF (ONB) is characterized by the presence of exposed bone or bone that can be probed through a fistula that persists for more than eight weeks in patients with a history of BF therapy and without history of head and neck radiotherapy and / or without metastatic disease in the jaws. The incidence of ONB increases with potency, duration of treatment and dose of BF received. Thus far, the pathophysiology of ONB is unclear, hampering prevention and treatment. The aim of this study was to objectively assess the effect of long-term high-dose Zoledronic Acid (ZA) on cancellous bone in the jaw and femur of Wistar rats. In order to link our findings to the physiopathology of ONB, the therapeutic regiment of a relevant ONB animal model was reproduced. Twelve Wistar rats were randomly divided in two groups: six received Zoledronic acid (ZA; 0.6 mg / kg) and six (Controls) received saline solution in the same volume. The compounds were administrated intraperitoneally in five doses each 28 days. The rats were killed after 150 days of the therapy onset. Mandibles and femurs were scanned using a high-resolution (14m) micro-computerized tomography (Micro-CT). For the first analysis carried in this study, cancellous bone morphometric data were calculates in the region of the second and first molar in the mandible and in the proximal femur using CTAnalyzer (Bruker, Belgium). For the second analysis five samples were cut into histological slices (5m) and stained with Hematoxylin and Eosin. In order to compare the same morphological structures in Micro-CT and histology, the Micro-CT images were aligned to histology. Alveolar bone morphometric data (Micro-CT) was calculated using CTAnalyzer (Bruker, Belgium) in the region between the mesial and distal roots of the first molar. Blood vessels density and bone histomorphometric data were calculated using Axiovision (Carl Zeiss, Germany) in the same region used for Micro-CT evaluation. Statistical significance of 5% (=0.05) was adopted. ZA treated rats presented significant increase in the percentage of bone volume (p<0.05) with thicker trabeculae and more compact bone with smaller marrow spaces in the mandible and femur. In the mandible, the increase in bone density and decrease of marrow spaces size was strongly correlated with the decrease in the vascular area noticed in the ZA group (p<0.05). In conclusion, long-term high-dose ZA treatment was significant associated with the increase of bone density and the diminution of medullary spaces and nutritive canals size as well as decrease in vascularity of the alveolar bone. Micro-CT investigation showed similar changes in bone structure in the mandible and femur in the ZA group.(AU)

Effects of ethanol consumption and alcohol detoxification on the biomechanics and morphology the bone in rat femurs / Efeitos do consumo de etanol e da desintoxicação alcóolica sobre a biomecânica e morfologia óssea em fêmur de ratos

Abstract The objective of this study was to verify the effects of ethanol consumption and alcohol detoxification on the biomechanics, area and thickness of cortical and trabecular bone in rat femur. This was an experimental study in which 18 male Wistar rats were used, with 40 days of age, weighing 179±2.5 g. The rats were divided into three groups (n=06): CT (control), AC (chronic alcoholic), DT (detoxification). After experimental procedures, the animals were euthanized by an overdose of the anesthetic and their femurs were collected for mechanical testing and histological processing. All animals did not present malnutrition or dehydration during experimentation period. Morphometric analysis of cortical and trabecular bones in rat femurs demonstrated that AC animals showed inferior dimensions and alcohol detoxification (DT) allowed an enhancement in area and thickness of cortical and trabecular bone. Material and structural properties data of AC group highlighted the harmful effects of ethanol on bone mechanical properties. The results of this study demonstrated that chronic alcoholic rats (AC) presented major bone damage in all analyzed variables. Those findings suggested that alcohol detoxification is highly suggested in pre-operative planning and this corroborates to the success of bone surgery and bone tissue repair. Thanks to the financial support offered by PROBIC – UNIFENAS.

Resumo O objetivo deste estudo foi verificar os efeitos do consumo de etanol e da desintoxicação alcoólica sobre a biomecânica, área e espessura do osso cortical e trabecular em fêmur de ratos. Este foi um estudo experimental no qual foram utilizados 18 ratos Wistar machos, com 40 dias de vida, pesando 179±2,5 g. Os ratos foram divididos em três grupos (n=06): CT (controle), AC (alcoolista crônico), e DT (desintoxicado). Após os procedimentos experimentais os animais foram eutanaziados por uma overdose de anestésico e os fêmures coletados para os testes mecânicos e processamento histológico. Todos os animais não apresentaram desnutrição ou desidratação durante o período de experimentação. As análises morfométrica do osso cortical e trabecular demonstraram que os animais do grupo AC apresentavam dimensões inferiores, enquanto nos animais do grupo DT observou-se um aumento na área e espessura do osso cortical e trabecular. Dados dos materiais e das propriedades estruturais óssea do grupo AC destacam os efeitos nocivos do etanol sobre as propriedades mecânicas do osso. Os resultados deste estudo demonstraram que os ratos do grupo AC apresentaram danos significativos no osso em todas as variáveis ​​analisadas. Esses resultados sugerem que a desintoxicação alcoólica é recomendada no planejamento pré-operatório e isso corrobora para o sucesso de cirurgias e reparação no tecido ósseo. Agradecemos ao apoio financeiro oferecido pelo PROBIC – UNIFENAS.

Biocompatibility and osteogenesis of the castor bean polymer doped with silica (SiO2) or barium titanate (BaTiO3) nanoparticles

PURPOSE: To evaluate the biocompatibility and osteogenesis of castor oil polymer doped with SiO2 or BaTiO3 nanoparticles. METHODS: Twenty four male rats Wistar were submitted to bone defect filled with castor oil polymer. The animals were distributed in two experimental groups had been formed with 12 animals each: Group 1 - Castor oil polymer doped with 0.30 grams of SiO2 replacing 0.30 grams of CaCO3. Group 2 - Castor oil polymer doped with 0.30 grams of BaTiO3 replacing 0.30 grams of CaCO3. Euthanasia occurred 30 and 60 days after surgery and the femurs were sent to histological analysis and MEV. RESULTS: The implants were biocompatible and allowed for progressive osteogenesis through osteoconduction in both observation periods. There was significant bone neoformation at 30 and 60 days in both groups within the histomorphometric evaluation, but group 1's osteogenesis was lesser in the 30 and 60-day periods observed when compared to the animals of group 2. The MEV morphometric evaluation evidenced a lesser percentage of osseous tissue filling within the BaTiO2-doped polymer. CONCLUSION: The castor oil polymer doped with SiO2 or BaTiO3 remained biocompatible and allowed for progressive osteogenesis in both observation periods. .

Role of Triticum aestivum aqueous extract in glucocorticoid induced osteoporosis in rats.

Administration of aqueous extract of T. aestivum (200 and 400 mg/kg/day, po, for 30 days) and risedronate (20 mg/kg, sc, five times a week for 30 days) following methyl prednisolone sodium succinate (10 mg/kg, sc, thrice a week for 4 weeks) induced osteoporosis in Wistar rats showed an increase in the serum levels of bone mineral content markers, decrease in the serum and urinary levels of bone resorption markers. An incline in strength of femur and tibia was seen particularly with 400 mg/kg of T. aestivum. Maintenance of calcium homeostasis, formation of collagen and scavenging of free radicals can plausibly be the mode of action of aqueous extract of T. aestivum thereby combating osteoporosis induced by glucocorticoids.

Assessment of methyl methacrylate genotoxicity by the micronucleus test

The aim of this study was to evaluate the genotoxic potential of methyl methacrylate (MMA) vapor by simulating standard occupational exposure of 8 hours per day and using the micronucleus test. We used 32 adult male Wistar rats divided into three groups: A - 16 rats exposed to MMA for 8 hours a day, B - Eight rats receiving single subcutaneous doses of cyclophosphamide on the first day of the experiment (positive control), C - Eight rats receiving only water and food ad libitum (negative control). Eight rats from group A and all of the rats from groups B and C were sacrificed 24 hours after beginning the experiment (acute exposure in group A). The remaining animals in group A were sacrificed 5 days after the experiment began (repeated exposure assessment in group A, simulating occupational exposure 40 hours/week). Femoral bone marrow was collected from each rat at the time of sacrifice for use in the micronucleus test. Two slides were completed per animal and were stained with Giemsa staining. Two thousand polychromatic erythrocytes were counted per animal. The Kruskal-Wallis test followed by a multiple comparisons test (Dunn test) was used for statistical analysis. The median number of micronuclei was 7.00 in the group exposed to MMA for 1 day, 2.00 in the group exposed to MMA for 5 days, 9.00 in the group exposed to cyclophosphamide (positive control) and 0.756 in the negative control group (p < 0.0001). MMA was genotoxic when measured after 1 day of exposure but was not evidently genotoxic after 5 days.

The effects of alpha-tocopherol supplementation on fracture healing in a postmenopausal osteoporotic rat model

OBJECTIVE: Osteoporosis increases the risk of bone fractures and may impair fracture healing. The aim of this study was to investigate whether alpha-tocopherol can improve the late-phase fracture healing of osteoporotic bones in ovariectomized rats. METHOD: In total, 24 female Sprague-Dawley rats were divided into three groups. The first group was sham-operated, and the other two groups were ovariectomized. After two months, the right femora of the rats were fractured under anesthesia and internally repaired with K-wires. The sham-operated and ovariectomized control rat groups were administered olive oil (a vehicle), whereas 60 mg/kg of alpha-tocopherol was administered via oral gavage to the alpha-tocopherol group for six days per week over the course of 8 weeks. The rats were sacrificed, and the femora were dissected out. Computed tomography scans and X-rays were performed to assess fracture healing and callus staging, followed by the assessment of callus strengths through the biomechanical testing of the bones. RESULTS: Significantly higher callus volume and callus staging were observed in the ovariectomized control group compared with the sham-operated and alpha-tocopherol groups. The ovariectomized control group also had significantly lower fracture healing scores than the sham-operated group. There were no differences between the alpha-tocopherol and sham-operated groups with respect to the above parameters. The healed femora of the ovariectomized control group demonstrated significantly lower load and strain parameters than the healed femora of the sham-operated group. Alpha-tocopherol supplementation was not able to restore these biomechanical properties. CONCLUSION: Alpha-tocopherol supplementation appeared to promote bone fracture healing in osteoporotic rats but failed to restore the strength of the fractured bone.

Influence of estrogen deficiency and tibolone therapy on trabecular and cortical bone evaluated by computed radiography system in rats / Influência da deficiência estrogênica e do tratamento com tibolona no osso trabecular e cortical avaliada pelo sistema de radiografia computadorizada em ratas

PURPOSE: To verify the effects of tibolone administration on trabecular and cortical bone of ovariectomized female rats by computed radiography system (CRS). METHODS: The experiment was performed on two groups of rats previously ovariectomized, one received tibolone (OVX+T) while the other did not (OVX), those groups were compared to a control group (C) not ovariectomized. Tibolone administration (1mg/day) began thirty days after the ovariectomy and the treatment remained for five months. At last, the animals were euthanized and femurs and tibias collected. Computed radiographies of the bones were obtained and the digital images were used to determine the bone optical density and cortical thickness on every group. All results were statistically evaluated with significance set at P<0.05 percent. RESULTS: Tibolone administration was shown to be beneficial only in the densitometric analysis of the femoral head, performing higher optical density compared to OVX. No difference was found in cortical bone thickness. CONCLUSION: Ovariectomy caused bone loss in the analyzed regions and tibolone administered in high doses over a long period showed not to be fully beneficial, but preserved bone mass in the femoral head.

OBJETIVO: Verificar o efeito da administração de tibolona no tecido ósseo cortical e trabecular de ratas castradas através de radiografia computadorizada. MÉTODOS: O experimento foi realizado em dois grupos de ratas previamente ooforectomizadas, onde um grupo recebeu tibolona (OVX+T) e o outro não (OVX). Esses grupos foram comparados a um grupo controle (C) não ooforectomizado. A administração de tibolona (1mg/dia) começou trinta dias após a ooforectomia e o tratamento teve duração de cinco meses. No final, os animais foram mortos e fêmures e tibias coletados. As radiografias computadorizadas dos ossos foram obtidas e as imagens digitais usadas para determinar a densidade óssea e a espessura cortical em todos os grupos. Todos os resultados foram avaliados estatisticamente com significância estabelecida a 5 por cento. RESULTADOS: A administração de tibolona mostrou ser benéfica apenas para análise densitométrica da cabeça do fêmur, apresentando maiores valores de densidade comparada ao grupo OVX. Nenhuma diferença significativa foi encontrada para espessura óssea cortical. CONCLUSÃO: A ooforectomia ocasionou perda óssea nas regiões analisadas e a tibolona administrada, em dose elevada e durante um longo período, mostrou não ser totalmente benéfica, porém preservou a massa óssea na cabeça femoral.

Changes in morphology of long bone marrow tissue of rats submitted to cryotherapy with liquid nitrogen / Alterações na morfologia do tecido medular de ossos longos de ratos submetido à crioterapia com nitrogênio líquido

PURPOSE: To study the main effects of local use of liquid nitrogen on bone marrow tissue in rats. METHODS: The femoral diaphyses of 42 Wistar rats were exposed to three local and sequential applications of liquid nitrogen for one or two minutes, intercalated with periods of five minutes of passive thawing. The animals were sacrificed after one, two, four and 12 weeks and the specimens obtained were analyzed histomorphologically. RESULTS: In the second experimental week of one-minute protocol, histological degree of inflammation obtained a mean score of one (mild), ranging from 0 (absent or scarce) and two (moderate) (Kruskal-Wallis test p=0.01). In the second experimental week of two-minute protocol, degree of inflammation to the medullar tissue obtained an average score of two (Kruskal-Wallis test p=0.01). CONCLUSION: The degree of inflammation of the bone marrow tissue was higher in protocol of three applications of two minutes compared to protocol of three applications of one minute.

OBJETIVO: Investigar os principais efeitos do uso local de nitrogênio líquido sobre o tecido medular ósseo em ratos. MÉTODOS: As diáfises femorais de 42 ratos Wistar foram expostas a três aplicações sequenciais locais de nitrogênio líquido por um ou dois minutos, intercaladas por períodos de cinco minutos de degelo espontâneo. Os animais foram sacrificados após uma, duas, quatro e 12 semanas e os espécimes obtidos foram analisados histomorfologicamente. RESULTADOS: Na segunda semana experimental do protocolo de um minuto, o grau histológico de inflamação obteve um escore médio de um (leve) variando entre 0 (ausente ou escarço) a dois (moderado) (Teste de Kruskal-Wallis p=0.01). Na segunda semana experimental do protocolo de dois minutos, o grau histológico de inflamação do tecido medular obteve um escore máximo de dois (moderado) (Teste de Kruskal-Wallis p=0.01). CONCLUSÃO: O grau de inflamação do tecido medular ósseo foi maior no protocolo de três aplicações de dois minutos comparado ao protocolo de três aplicações de um minuto.

Ação local do alendronato sódico na reparação óssea de ratos espontaneamente hipertensos (SHR) / Local action of sodium alendronate in bone repair of spontaneously hypertensive rat (SHR)

FUNDAMENTO: A hipertensão arterial é uma desordem caracterizada por alterações relevantes no tecido ósseo. O alendronato sódico tem indicação no tratamento de doenças ósseas, por causa de sua afinidade pela hidroxiapatita, inibindo as reabsorções ósseas. OBJETIVO: Analisar a ação local do alendronato sódico na reparação óssea de ratos espontaneamente hipertensos (SHR). MÉTODOS: Um defeito ósseo foi criado no fêmur esquerdo de 80 ratos. De acordo com o material utilizado no local, criaram-se quatro grupos: controle (C), amido (Am), alendronato 1 mol (A1) e alendronato 2 mol (A2). Após 7 e 21 dias, os animais foram sacrificados. Foram realizadas análises histológicas e histomorfométricas e os dados foram submetidos a análise de variância (ANOVA) e teste de Tukey (5 por cento). RESULTADOS: Aos 7 dias, observou-se, na área do defeito, tecido conjuntivo com hemorragia e inflamação em todos os grupos. Alguns apresentavam matriz osteóide. Os grupos A1 e A2 apresentaram, ainda, uma rede de fibrina. Aos 21 dias, as trabéculas ósseas fechavam praticamente a extensão do defeito nos grupos C e Am. No grupo A1 de animais machos, observaram-se trabéculas que se irradiavam do canal medular até a área do defeito. Nos grupos A1 e A2, constatou-se apenas a presença de tecido conjuntivo com mínima deposição de osteóide. Um achado histológico marcante foi a formação de tecido ósseo extracortical subperiosteal nos animais dos grupos A1 e A2. CONCLUSÃO: Concluiu-se que a administração do alendronato sódico não contribuiu para o reparo ósseo nos ratos SHR, mas possivelmente tenha sido responsável pelas formações ósseas extracorticais observadas.

BACKGROUND: The arterial hypertension is a disorder characterized by relevant alterations in the bone tissue. The sodium alendronate is indicated in the treatment of bone diseases, because of its affinity with the hydroxyapatite, inhibiting the bone reabsorptions. OBJECTIVE: To analyze local action of the sodium alendronate in the bone repair of spontaneously hypertensive rat (SHR). METHODS: A bone defect was created in the left femur of 80 rat. In agreement with the material used at the place, four groups were created: control (C), starch (St), alendronate 1 mol (A1) and alendronate 2 mol (A2). After 7 and 21 days, the animals were sacrificed. Histomorfometrical and histological analyses were accomplished and the data were submitted the variance analysis (ANOVA) and test of Tukey (5 percent). RESULTS: At 7 days, in the area of the defect, conjunctive tissue with hemorrhage and inflammation in all of the groups was observed. Some presented osteoid matrix. The groups A1 and A2 presented, further, a fibrin net. At 21 days, the bone trabeculae practically closed the extension of the defect in the groups C and St. In the group A1 of male animals, trabeculae were observed that irradiated from the medullary canal to the area of the defect. In the groups A1 and A2, only presence of conjunctive fabric with low osteoid deposit was observed. An outstanding histological discovery was the formation of extracortical subperiosteal bone tissue in animals of the groups A1 and A2. CONCLUSION: The administration of sodium alendronate did not contribute to bone repair in SHR rat, but possibly has been responsible for the extracortical bone formation observed.

High Concentrations of Pamidronate in Bone Weaken the Mechanical Properties of Intact Femora in a Rat Model

PURPOSE: Bisphosphonates have been used to treat osteoporosis for more than ten years. However, complications associated with long-term administration of bisphosphonates, such as nonunion after pelvic insufficiency fracture or osteonecrosis of the jaw, have been recently reported in the literature. We investigated the relationships among the mechanical properties of the intact rat femur as well as healing fracture calluses and the intraosseous concentration of pamidronate (ICP), after long-term administration of pamidronate in a rat osteoporosis model. MATERIALS AND METHODS: We performed bilateral ovariectomy in 25 3-month-old female Sprague-Dawley rats. Beginning three months after ovariectomy, disodium pamidronate (0.5mg/kg) was injected every month. After the six-month administration period, the left femoral shaft was fractured using the closed fracture technique. Five weeks after fracture, 23 rats were euthanized and both femora were removed. We checked the mechanical properties of the intact (right) and fractured (left) femora using a three-point bending technique. Intraosseous concentration of pamidronate was checked by high-performance liquid chromatography. RESULTS: The mean ICP was 61.8+/-15.7ng/mg of bone. High ICP decreased the ultimate load to failure, stiffness, and ultimate stress of the intact femora (p=0.015, 0.027, 0.039, respectively). There was a tendency to decrease the ultimate load to failure in the healing callus when the ICP increased (p= 0.183). High ICP decreased the bone mineral density of the femoral head (p=0.005). CONCLUSION: High concentrations of pamidronate in intact bone decreased the bone mineral density and weakened the mechanical strength of the rat femora. The mechanical strength of the early healing callus was not correlated with concentration of pamidronate in the bone.

Comparison of tissue reaction and osteointegration of metal implants between hydroxyapatite/Ti alloy coat: an animal experimental study.

BACKGROUND: One important clinical application of hydroxyapatite (HA) is coating on metal implants to stimulate osteo-integration thus enhancing fixation of the implant to bone, especially plasma-sprayed HA coating applied on Ti alloy substrate. The poor bonding strength between HA and Ti alloy has been of great concern to orthopedists. The biocomptable coat such as Ti alloy (TiO2) coat is one method to improve adhesive strength. OBJECTIVE: The objective of this study was to detect and analyze possible differences in bone formation, bone integration and tissue reaction between group I (uncoated Titanium), group II (Hydroxyapatite coated Titanium), and group III (Hydroxyapatite/TiO2 coated Titanium) implant specimens when embedded into bony hosts. METHOD: Rectangular specimens were implanted into the femoral bone of adult dogs in randomly different sites including: proximal left, proximal right, distal left, distal right. The tailor-made implant specimens were inserted in 5 x 5 mm preprepared sockets. Radiographic evaluation was taken at 0, 1, 3 and 6 months. All animals were sacrificed at 3 and 6 months post implantation. The femoral bone containing implants were dissected and then prepared to be further investigated. The bone-implant interface was analyzed by H&E surface staining, radiography and scanning electron microscopy. Data concerning percentage of osteointegration and adhesiveness of hydroxyapatite layer from different kinds of implants along the entire length of each implants were collected and analyzed for evaluation of any significant differences. RESULTS: No osteo-integration was noted in Group I, but there was 25.57 per cent osteointegration in Group II and 28.63 per cent in Group III. No statistically significant differences were observed between Group II and Group III. However, the coating layer in Group II was found to have detached, in some area, from the metal substrate. Histologically, no adverse tissue reaction was found around any kind of implant. CONCLUSION: Biocompatable bond coat is one of the methods to improve adhesive strength of hydroxyapatite coated implants. In the present study it could be concluded that, besides the improvement in adhesiveness, the intervening TiO2 coating layer had no negative effect concerning bone formation and integration and also showed no adverse surrounding soft tissue reaction.

Effect of 17á-estradiol or alendronate on the bone densitometry, bone histomorphometry and bone metabolism of ovariectomized rats

The objective of the present study was to evaluate the effect of 17á-estradiol or alendronate in preventing bone loss in 3-month-old ovariectomized Wistar rats. One group underwent sham ovariectomy (control, N = 10), and the remaining three underwent double ovariectomy. One ovariectomized group did not receive any treatment (OVX, N = 12). A second received subcutaneous 17á-estradiol at a dose of 30 æg/kg for 6 weeks (OVX-E, N = 11) and a third, subcutaneous alendronate at a dose of 0.1 mg/kg for 6 weeks (OVX-A, N = 8). Histomorphometry, densitometry, osteocalcin and deoxypyridinoline measurements were applied to all groups. After 6 weeks there was a significant decrease in bone mineral density (BMD) at the trabecular site (distal femur) in OVX rats. Both alendronate and 17á-estradiol increased the BMD of ovariectomized rats, with the BMD of the OVX-A group being higher than that of the OVX-E group. Histomorphometry of the distal femur showed a decrease in trabecular volume in the untreated group (OVX), and an increase in the two treated groups, principally in the alendronate group. In OVX-A there was a greater increase in trabecular number. An increase in trabecular thickness, however, was seen only in the OVX-E group. There was also a decrease in bone turnover in both OVX-E and OVX-A. The osteocalcin and deoxypyridinoline levels were decreased in both treated groups, mainly in OVX-A. Although both drugs were effective in inhibiting bone loss, alendronate proved to be more effective than estradiol at the doses used in increasing bone mass