Os efeitos de um programa de atividade física de carga progressiva nas propriedades físicas e na força óssea de ratas osteopênicas

Background: Many studies have shown that physical exercises are able to stimulate bone formation and increase bone mass, constituting a therapeutic modality to treat bone loss due to osteoporosis. However, some points about the intensity, duration and frequency of the exercises remain confusing and contradictory. Thus, the aim of this study was to determine the effects of a progressive loading exercise program on femur of osteopenic rats. To induce osteopenia we used the animal model of ovariectomy (OVX). Forty animals was studied and divided into 4 groups: sham-operated sedentary (SS); ovariectomy-sedentary (OS); sham-operated training (ST) and ovariectomy training (OT). The trained groups performed jumps into water: 4 series of 10 jumps each, with an overload of 50% to 80% of the animal's body weight, during 8 weeks. Femora were submitted to a physical properties evaluation, a biomechanical test, calcium and phosphorus content measurement and a morphometric histological evaluation. Results: osteopenic animals showed a decrease of bone strength and lower values of bone weights, bone density and calcium content. The exercised osteopenic rats showed higher values of geometrical, physical properties, bone strength and calcium content compared to controls. The results of the present study indicate that the progressive loading exercise program had stimulatory effects on femora of osteopenic rats. It seems that the intensity and duration of the protocol used produced bone structural adaptations, which contributed to reverse bone loss due to ovariectomy.

Determinação da densidade mineral e da elasticidade óssea após a aplicação de ondas de choque extracorpóreas no terceiro metacarpiano de equinos atletas

The porpoise of this study was to evaluate the effects of extracorporeal shock waves in third metacarpus bone from healthy horses by determination of bone elasticity. It were used 20 Thoroughbred horses, male and female, with two years old, on top of training and selected as the state healthy. At the beginning of the experiment (D0), all animals were submitted for evaluation of bone elasticity held in the third metacarpus bone. The animals were divided into two groups (Control Group - CG and Experimental Group - EG). The application of extracorporeal shock wave therapy (ESWT) was performed on the right forelimb of the animals in the experimental group in the same place evaluated for bone elasticity and was used apparatus for extracorporeal therapy of waves with 0.15 mJ/mm2 energy flux density and 2000 pulses with E6R20 probe, with focus feature of the shock wave of 20 mm. The ESWT were repeated every 21 days, a total of three sessions (D0, D21 and D42). The analysis of bone elasticity determination was realized at D21, D42 and D72. The average of speed ultrasound differed between groups at D21, D42 and D72, and the animals from EG had lower bone mineral density after applications of ESWT. There was also difference in the analysis of bone mass (Z-Score) between the groups at D21 and D42, which animals from EG showed a significant decrease in bone mass. The risk of fracture was higher in animals from experimental group at D21. It was concluded that ESWT is able to promote change in bone mineral density.

Experimental development of bisphosphonate-related osteonecrosis of the jaws in rodents

Osteonecrosis of the jaw (ONJ) following the use of bisphosphonates has become of increased interest in the scientific community, due in particular to its as-yet-unsolved pathogenesis. An experimental model of ONJ was induced in normal male rats [alendronate (ALN); 1 mg/Kg/day; n = 10] and matched controls (saline solution; n = 10). After 60 days of drug treatment, all animals were subjected to extractions of the left first lower molars and were euthanized at 3 and 28 days postsurgery. The following analyses were performed: (i) descriptive and quantitative (scores) histological evaluation, (ii) stereometry of distal sockets and (iii) biochemical measurement of C-telopeptide cross-linked collagen type I (CTX) and bone-specific alkaline phosphatase (BALP). The results showed that 28 days postsurgery the animals treated with ALN had areas of exposed and necrotic bone, associated with significant infection, especially in the interalveolar septum area and crestal regions, compared with controls. The levels of CTX, BALP and bone volume, as well as the degrees of inflammation and vascularization, were significantly reduced in these animals. Therefore, analysis of the data presented suggests that ALN therapy is associated with the development of osteonecrosis in the jaws of rodents after tooth extraction. © 2012 International Journal of Experimental Pathology.

Magnesium deficiency results in an increased formation of osteoclasts

Magnesium (Mg2+) deficiency is a frequently occurring disorder that leads to loss of bone mass, abnormal bone growth and skeletal weakness. It is not clear whether Mg2+ deficiency affects the formation and/or activity of osteoclasts. We evaluated the effect of Mg2+ restriction on these parameters. Bone marrow cells from long bone and jaw of mice were seeded on plastic and on bone in medium containing different concentrations of Mg2+ (0.8 mM which is 100% of the normal value, 0.4, 0.08 and 0 mM). The effect of Mg2+ deficiency was evaluated on osteoclast precursors for their viability after 3 days and proliferation rate after 3 and 6 days, as was mRNA expression of osteoclastogenesis-related genes and Mg2+-related genes. After 6 days of incubation, the number of tartrate resistant acid phosphatase-positive (TRACP+) multinucleated cells was determined, and the TRACP activity of the medium was measured. Osteoclastic activity was assessed at 8 days by resorption pit analysis. Mg2+ deficiency resulted in increased numbers of osteoclast-like cells, a phenomenon found for both types of marrow. Mg2+ deficiency had no effect on cell viability and proliferation. Increased osteoclastogenesis due to Mg2+ deficiency was reflected in higher expression of osteoclast-related genes. However, resorption per osteoclast and TRACP activity were lower in the absence of Mg2+. In conclusion, Mg2+ deficiency augmented osteoclastogenesis but appeared to inhibit the activity of these cells. Together, our in vitro data suggest that altered osteoclast numbers and activity may contribute to the skeletal phenotype as seen in Mg2+ deficient patients. © 2012 Elsevier Inc. All rights reserved.

Estudo clínico, biomecânico e histológico do efeito da menopausa induzida por ooforectomia no tecido ósseo. Modelo experimental em ratas

Pós-graduação em Bases Gerais da Cirurgia - FMB

Hidroterapia e eletroterapia em ratos com denervação do nervo isquiático

Pós-graduação em Ciência Animal - FMVA

Efeitos da castração e androgenização neonatal sobre o dimorfismo sexual esquelético e secreção de leptina e corticosterona em ratos

Pós-graduação em Ciências Fisiológicas - FOA

Perfil metabólico de cálcio e ósseo de pacientes soropositivos para HIV em uso ou não da terapia antirretroviral

Pós-graduação em Alimentos e Nutrição - FCFAR

Expressão das proteínas osteoprotegerina, RANK e RANKL durante o processo de reparo alveolar em ratos: estudo imunoistoquímico

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Avaliação da densitometria óssea em fêmur de rato após consumo de álcool e fluoreto de sódio

Pós-graduação em Odontologia - FOA

Perfil da ingestão de alimentos e de nutrientes relacionados à saúde óssea, de mulheres com mais de 60 anos, moradoras da cidade de Bauru, São Paulo

Pós-graduação em Fisiopatologia em Clínica Médica - FMB

Prática de atividade física e qualidade de vida de pacientes com osteoporose e osteopenia

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação da densidade mineral óssea e os fatores a ela associados em indivíduos adultos com Diabetes Mellitus

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo da fragilidade em fêmures de ratos diabéticos pela análise densitométrica e biomecânica

Pós-graduação em Ciência Animal - FMVA

Associação entre a densidade mineral óssea da coluna lombar e do fêmur e do perfil lipídico e lipoprotéico em pacientes pós-menopáusicas com osteoporose

Pós-graduação em Ginecologia, Obstetrícia e Mastologia - FMB