Abstract The aim of this systematic review was to evaluate published papers regarding the micronucleus assay in oral mucosal cells of patients undergoing orthodontic therapy (OT). A search of the scientific literature was made in the PubMed, Scopus, and Web of Science databases for all data published until November, 2021 using the combination of the following keywords: “fixed orthodontic therapy,” “genetic damage”, “DNA damage,” “genotoxicity”, “mutagenicity”, “buccal cells”, “oral mucosa cells,” and “micronucleus assay”. The systematic review was designed according to the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines. Nine studies were retrieved. Some authors demonstrated that OT induces cytogenetic damage in oral mucosal cells. Out of the nine studies included, two were classified as strong, five as moderate, and two as weak, according to the quality assessment components of the Effective Public Health Practice Project (EPHPP). Meta-analysis data revealed no relationship between mutagenicity in oral cells and OT in different months of treatment. At one month, the SMD = 0.65 and p = 0.08; after three months of OT, the SMD = 1.21 and p = 0.07; and after six months of OT, the SMD = 0.56 and p = 0.11. In the analyzed months of OT, I2 values were >75%, indicating high heterogeneity. In summary, this review was not able to demonstrate that OT induces genetic damage in oral cells. The study is important for the protection of patients undergoing fixed OT, given that mutagenesis participates in the multi-step process of carcinogenesis.

Abstract Background: The knee osteoarthritis (OA) is a joint disease characterized by degradation of articular cartilage that leads to chronic inflammation. Exercise programs and photobiomodulation (PBM) are capable of modulating the inflammatory process of minimizing functional disability related to knee OA. However, their association on the concentration of biomarkers related to OA development has not been studied yet. The aim of the present study is to investigate the effects of PBM (via cluster) with a physical exercise program in functional capacity, serum inflammatory and cartilage degradation biomarkers in patients with knee OA. Methods: Forty-two patients were randomly allocated in 3 groups: ESP: exercise + sham PBM; EAP: exercise + PBM and CG: control group. Six patients were excluded before finished the experimental period. The analyzed outcomes in baseline and 8-week were: the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) and the evaluation of serum biomarkers concentration (IL-1β, IL-6, IL-8, IL-10 e TNF-α, and CTX-II). Results: An increase in the functional capacity was observed in the WOMAC total score for both treated groups (p < 0.001) and ESP presents a lower value compared to CG (p < 0.05) the 8-week post-treatment. In addition, there was a significant increase in IL-10 concentration of EAP (p < 0.05) and higher value compared to CG (p < 0.001) the 8-week post-treatment. Moreover, an increase in IL-1β concentration was observed for CG (p < 0.05). No other difference was observed comparing the other groups. Conclusion: Our data suggest that the physical exercise therapy could be a strategy for increasing functional capacity and in association with PBM for increasing IL-10 levels in OA knee individuals. Trial registration: ReBEC (RBR-7t6nzr).

Abstract This study characterized the morphological aspects of marine collagen - spongin (SPG) extract from marine sponges, as well as, evaluating its in vitro and in vivo biological performance. Aplysina fulva marine sponge was used for the SPG extraction. It was investigated the physicochemical and morphological properties of SPG by using scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction and compared to PMMA and bovine collagen. Additionally, the SPG cytotoxicity and its influence on cell proliferation, through in vitro tests. Moreover, the in vivo biological response was investigated using an experimental model of tibial bone defect. The results demonstrated that SPG presented an irregular granular aspect, with a composition of OH, C=O, NH, CN and an amorphous profile. Also, in vitro viability results for the L929 and MC3T3 cell lines cultured with SPG extracts demonstrated normal growth in comparison to controls, except for MC3T3 viability at day 3. For in vivo analysis, using tibial bone defects in rats, SPG treated animals presented an increased rate of material resorption and higher granulation and bone formation deposition in the region of the defect, mainly after 45 days. As a conclusion, SPG was successfully extracted. The in vitro and in vivo studies pointed out that SPG samples produced an increase in L929 and MC3T3 viability and improved the performance in tibial bone defects. It can be concluded that SPG can be used as a bone graft for bone regeneration.

Abstract Research on biomaterials of natural origin has gained prominence in the literature. Above all, marine sponges, due to their architecture and structural components, present a promising potential for the engineering of bone tissue. In vitro studies demonstrate that a biosilica of marine sponges has osteogenic potential. However, in vivo works are needed to elucidate the interaction of biosilica (BS) and bone tissue. The objective of the study was to evaluate the morphological and chemical characteristics of BS compared to Bioglass (BG) by scanning electron microscopy (SEM) and X-ray dispersive energy (EDX) spectroscopy. In addition, to evaluate the biological effects of BS, through an experimental model of tibial bone defect using histopathological, histomorphometric, immunohistochemical (IHC) and mechanical tests. SEM and EDX demonstrated the successful extraction of BS. Histopathological analysis demonstrated that Control Group (GC) had greater formation of newly formed bone tissue compared to BG and BS, yet BG bone neoformation was greater than BS. However, BS showed material degradation and granulation tissue formation, with absence of inflammatory process and formation of fibrotic capsule. The results of histomorphometry corroborate with those of histopathology, where it is worth emphasizing the positive influence of BS in osteoblastic activity. IHQ demonstrated positive VEGF and TGF-β immunoexpression for GC, BS and BG. In the mechanical test no significant differences were found. The present results demonstrate the potential of BS in bone repair, further studies are needed other forms of presentation of BS are needed.

Abstract The aim of this study was to evaluate the effectiveness of 3 different fluences of low-level laser therapy (LLLT) in intermediate period of spinal cord repair using an experimental model in rats. Thirty two rats were randomly divided into four experimental groups: Control Group (CG); Laser treated group 500 J/cm² (L-500); Laser treated group 750 J/cm² (L-750) and Laser treated group 1000 J/cm² (L-1000). Spinal cord injury (SCI) was performed by an impactor equipment (between 9th and 10th thoracic vertebrae), with a pressure of 150 kdyn. Afterwards, the injured region was irradiated daily for 14 consecutive sessions, using an 808 nm laser, at the respective fluence of each experimental groups. Locomotor function and tactile sensitivity were performed on days 1 and 15 post-surgery. Animals were euthanized 15 days post-surgery and samples were retrieved for histological and immunohistochemistry analysis. Functional behavior and tactile sensitivity were improved after laser irradiation. Moreover, higher fluencies of LLLT reduced the volume of injury. Additionally, LLLT produced a decreased CD-68 expression. These results demonstrated that, for an intermediate period of SCI repair, LLLT at higher fluences, was effective in promoting functional recovery and modulating the inflammatory process in the spinal cord of rats after traumatic SCI.

Resumo Introdução: O envelhecimento está associado a mudanças estruturais no tecido muscular, que levam à perda da independência funcional. A preservação da força muscular através do treinamento de força e, recentemente, da terapia laser de baixa intensidade (TLBI), têm alta significância clínica. Objetivo: investigar os efeitos da fotobiomodulação (808 nm, 100 mW, 35,7 W/cm2 e 7 J) associada a um programa de força muscular direcionado à força do músculo do quadríceps, equilíbrio e capacidade funcional de mulheres idosas. Métodos: 35 mulheres saudáveis entre 60 e 70 anos de idade foram divididas em dois grupos: Grupo Placebo (n = 13) e Grupo Ativo (n = 14). O protocolo de exercício consistiu no exercício de flexão e extensão de joelhos seguido da aplicação da fotobiomodulação placebo ou ativa, 2 vezes por semana por 8 semanas consecutivas. Resultados: mostraram um aumento significativo no TC6 (p = 0,001), SPPB (p = 0,006) e 1-RM (p = 0,001) em ambos os grupos. O programa de treinamento de força associado a fotobiomodulação ativa promoveu um significativo aumento relativo à avaliação inicial, no índice de estabilidade medial/lateral direito (p = 0,007) e diminuição no Teste de Risco de Queda (p = 0,005). Conclusão: o treinamento de força produziu um significativo aumento da força muscular e da funcionalidade e, quando combinado com a fotobiomodulação, foi significativo em promover estabilidade postural e diminuição do risco de queda.

Abstract Introduction: Aging is associated with structural changes in muscle tissue, which leads to the loss of functional independence. The preservation of the muscle strength through strength training, and recently, low-level laser therapy (LLLT), has high clinical significance. Objective: to investigate the effects of photobiomodulation (PBM - 808 nm, 100 mW, 35.7 W/cm2 and 7 J) associated with a strength training program on quadriceps muscle strength, balance and functional capacity in elderly women. Methods: Thirty-five healthy women between 60 to 70 years old were divided into two groups: Placebo Group (n = 13) and Active Group (n = 14). The exercise protocol consisted of knee flexion-extension exercise followed by application of PBM placebo or active, twice a week for 8 consecutive weeks. Results: showed a significant increase in 6MWT (p = 0.001), SPPB (p = 0.006) and 1-MR (p = 0.001) in both groups. The strength training program associated with PBM active improved a significant increase, relative to baseline, to the right medial/lateral stability index (p = 0.007) and decrease in the Fall Risk Test (p = 0.005). Conclusion: the strength training produced a significant increase of muscle strength and functionality and when combined with the PMB it was significant in the improvement of postural stability and decrease of fall risk.

Resumen Introducción: Envejecimiento está asociado a cambios estructurales en el tejido muscular, que llevan a la perdida de la independencia funcional. La preservación de la fuerza muscular a través del entrenamiento de fuerza, y recientemente, la terapia láser de baja intensidad (TLBI), tiene alta significancia clínica. Objetivo: investigar los efectos de la fotobiomodulación (808nm, 100mW, 35,7 W/cm2 y 7J) asociado a un programa de fuerza muscular del músculo cuádriceps, equilibrio y capacidad funcional de mujeres mayores. Métodos: 35 mujeres sanas entre 60 y 70 años de edad fueran repartidas en dos grupos: Grupo Ejercicio y Láser Placebo (n = 13) y Grupo Ejercicio y Láser Activo (n = 14). El protocolo de ejercicio consistió en flexión extensión de rodillas seguido de la aplicación de la fotobiomodulación placebo o activa, 2 veces en la semana durante 8 semanas consecutivas. Resultados: mostraron un aumento significativo en el TC6 (p = 0,001), SPPB (p = 0,006) y 1-RM (p = 0,001) en los dos grupos. El programa de entrenamiento de fuerza asociado a la fotobiomodulación activa promovió un aumento significativo, relativo a la evaluación inicial, en el índice de estabilidad medial / lateral derecho (p = 0,007) y disminución en la prueba de riesgo de caída (p = 0,005). Conclusión: El entrenamiento de fuerza produjo un aumento significativo de la fuerza muscular y funcionalidad, incluso cuando se combinó con la fotobiomodulación fue significativo en promover estabilidad postural y disminución del riesgo de caída.

RESUMO Introdução: A laserterapia de baixa potência tem entre seus propósitos auxiliar a recuperação de tecidos biológicos, atenuando os efeitos da fadiga muscular e contribuindo com a melhora do desempenho em atletas. Aspectos metodológicos ainda limitam as conclusões do efeito agudo da laserterapia sobre o desempenho muscular. Objetivo: Verificar o efeito agudo do laser terapêutico de baixa potência na fadiga induzida do bíceps braquial de atletas de voleibol. Métodos: Este foi um estudo randomizado e duplo-cego, aprovado pelo Comitê de Ética da UNESP de Marília. Participaram do estudo 19 atletas de voleibol de ambos os sexos. Realizou-se coleta de dados eletromiográficos do músculo bíceps braquial no exercício isométrico de flexão de cotovelo antes e após a aplicação do laser terapêutico. Um haltere com 75% do pico de força, obtido por uma célula de carga, foi utilizado para o protocolo de fadiga. Em seguida, os voluntários foram submetidos à aplicação do laser (ativo ou placebo) em seis pontos do músculo bíceps braquial. Os dados eletromiográficos foram analisados no domínio da frequência, utilizando-se o software Myosystem®. Verificou-se a distribuição de normalidade dos dados pelo teste de Shapiro-Wilk, e utilizou-se Anova (split plot) de medidas repetidas a fim de testar a interação entre tempo e grupo. Resultados: Para nenhuma das variáveis analisadas foi observada interação significativa entre grupo e tempo, indicando que o grupo irradiado não apresentou vantagens com relação ao grupo placebo. Conclusão: Após o protocolo de fadiga proposto, uma única aplicação de laser de baixa potência não foi suficiente para produzir efeitos positivos no desempenho de força e no sinal eletromiográfico do músculo bíceps braquial de atletas de voleibol.

ABSTRACT Introduction: Low-power laser therapy has among its aims to aid the recovery of biological tissues, attenuating the effects of muscle fatigue and contributing to the improvement of performance in athletes. Methodological aspects still limit the conclusions of the acute effect of laser therapy on muscular performance. Objective: To verify the acute effect of low-power therapeutic laser in the induced fatigue in biceps brachii of volleyball athletes. Methods: This was a randomized double-blind study, approved by Institutional Review Board of UNESP, Marília. Nineteen volleyball athletes of both sexes participated in this study. Electromyographic data were collected from the biceps brachii muscle in isometric exercise of the elbow flexion before and after the application of the therapeutic laser. A dumbbell with 75% of the force peak, obtained by a load cell, was used for the fatigue protocol. The volunteers then underwent laser (active or placebo) application on six points of the biceps brachii muscle. The EMG data were analyzed in the frequency domain using the Myosystem ® software. The distribution of normality was verified by the Shapiro-Wilk test, and repeated measures ANOVA (split plot) was used to test the interaction between time and group. Results: No significant interaction between group and time was observed for any analyzes variables, indicating that the irradiated group did not show advantages over the placebo group. Conclusion: After the proposed fatigue protocol, a single low-power laser application was not sufficient to produce positive effects on strength performance and on the electromyographic signal of the biceps brachii muscle of volleyball athletes.

RESUMEN Introducción: La láserterapia de baja potencia tiene entre sus propósitos auxiliar la recuperación de los tejidos biológicos, atenuando los efectos de la fatiga muscular y contribuyendo con la mejora del desempeño en atletas. Los aspectos metodológicos todavía limitan las conclusiones del efecto agudo de la láserterapia sobre el rendimiento muscular. Objetivo: Verificar el efecto agudo del láser terapéutico de baja potencia en la fatiga inducida del bíceps braquial de atletas de voleibol. Métodos: Fue un estudio aleatorizado y doble ciego, aprobado por el Comité de Ética de la UNESP de Marília. Participaron del estudio 19 atletas de voleibol de ambos sexos. Se realizó la recolección de datos electromiográficos del músculo bíceps braquial en ejercicio isométrico de flexión de codo antes y después de la aplicación del láser terapéutico. Se utilizó una mancuerna con un 75% del pico de fuerza, obtenido por una célula de carga para el protocolo de fatiga. A continuación, los voluntarios fueron sometidos a la aplicación del láser (activo o placebo) en seis puntos del músculo bíceps braquial. Los datos electromiográficos se analizaron en el ámbito de la frecuencia, utilizando el software Myosystem ® . Se verificó la distribución de la normalidad de los datos por la prueba de Shapiro-Wilk, y se utilizó Anova (split plot) de medidas repetidas para probar la interacción entre tiempo y grupo. Resultados: Para ninguna de las variables analizadas se observó interacción significativa entre grupo y tiempo, indicando que el grupo irradiado no presentó ventajas con relación al grupo placebo. Conclusión: Después del protocolo de fatiga propuesto, una única aplicación láser de baja potencia no fue suficiente para producir efectos positivos en el desempeño de fuerza y en las señales electromiográficas del músculo bíceps braquial de atletas de voleibol.

The main purpose of the present study was to investigate the effects of low-level laser therapy (LLLT) used in two different fluencies on injured skeletal muscle after cryolesion by means of histopathological analysis and immunohistochemistry for COX-2. A total of sixty male Wistar rats were randomly distributed into three groups: injured animals without any treatment; 808 nm laser treated group, at 10 J/cm² and 808 nm laser treated group, at 50 J/cm². Each group was divided into two different subgroups (n=10) on days 6 and 13 post-injury. The results showed that the animals irradiated with laser at 10 J/cm² or 50 J/cm² presented the areas with cell infiltrate and pointed out to minor and mild areas with destroyed zones compared with the control group. Also, a COX-2 downregulation was noticed in the groups exposed to laser at two fluences evaluated in this study. Significant statistically differences (p<0.05) were noticed to collagen deposition in the laser treated animals, with the fluence of 50 J/cm² when compared to the other groups on day 13 post-surgery. Taken together, these results suggested that laser therapy could have positive effects on muscle repair in the rats after cryolesion.

OBJETIVO: Verificar os efeitos da associação do Biosilicato® com o US e com o LLLT no processo de consolidação óssea em ratos, a partir da análise biomecânica e histológica. MÉTODOS: Foram utilizados 40 ratos machos distribuídos em quatro grupos (n = 10): grupo controle fratura sem tratamento (GCF); grupo tratado com Biosilicato® (GB); grupo tratado com Biosilicato® + laser (GBL); grupo tratado com Biosilicato® + US (GBUS). RESULTADOS: A análise biomecânica não apresentou diferença estatisticamente significativa nos grupos após o período experimental de 14 dias. Na análise morfométrica, o grupo controle apresentou presença moderada de tecido ósseo neoformado no interior dos defeitos e o grupo tratado com Biosilicato® apresentou resultados semelhantes. No entanto, foi observado o potencial osteogênico do biomaterial, uma vez que houve grande presença de células e tecido ósseo ao redor das partículas. Interessantemente, os grupos Biosilicato® associado ao laser terapêutico e ao US demonstraram quantidades menores de deposição de tecido ósseo quando comparados aos grupos controle fratura e Biosilicato®. CONCLUSÃO: A partir dos dados deste estudo podemos concluir que o Biosilicato® foi capaz de acelerar e potencializar a recuperação óssea, através da modulação do processo inflamatório e da estimulação da formação de tecido ósseo novo. No entanto, quando a LLLT ou o US foram associados, não foram encontrados resultados positivos.

OBJECTIVE: Verify the effects of the association between Biosilicate® and ultrasound and, Biosilicate® and laser in bone consolidation process of rats, through the biomechanical and histological analysis. METHODS: Forthy male rats were used. The animals were randomized into four groups (n=10): control group fracture no treated (CGF); group treated with Biosilicate® (BG); group treated with Biosilicate® and laser (BLG); group treated with Biosilicate® and ultrasound (BUG). RESULTS: The biomechanical analysis showed no significant difference among any groups after 14 days post-surgery. In the morphometric analysis, the control group showed moderate presence of new formed bone tissue inside the defects areas and the Biosilicate® group showed similar results. Despite those facts, the biomaterial osteogenic potential was demonstrated by the great amount of cells and bone tissue around the particles. Curiously, the Biosilicate® plus laser or ultrasound groups showed lower amounts of bone tissue deposition when compared with control fracture and Biosilicate® groups. CONCLUSION: The data from this study can conclude that Biosilicate® was able to accelerate and optimized the bone consolidation, through the modulation of the inflammatory process and the stimulation of new bone formation. However, when resources were associated, there are no positive results.

OBJETIVO: Fazer uma revisão bibliográfica a respeito dos efeitos dos principais recursos eletrofísicos utilizados na aceleração do metabolismo ósseo e no tratamento da osteoporose. ANTECEDENTES: A Organização Mundial da Saúde (OMS) define a osteoporose como doença esquelética sistêmica caracterizada por diminuição da massa óssea e deterioração microarquitetural do tecido ósseo, com consequente aumento da fragilidade óssea e susceptibilidade à fratura. Vários tratamentos medicamentosos e não medicamentosos vêm sendo desenvolvidos na tentativa de aumentar a massa óssea e prevenir a osteoporose. Dentro desse contexto, os recursos eletrofísicos vêm tendo um papel de destaque, como recursos que apresentam um potencial osteogênico, capazes de estimular a proliferação de osteoblastos e biomodular o metabolismo ósseo. ESTRATÉGIA DE PESQUISA: Foram consultadas as bases de dados: The Cochrane Library, MEDLINE, Embase, LILACS, SciELO, referências dos artigos identificados, e contato com especialisas em laser, entre os anos de 1983 e 2009. CRITÉRIOS DE SELEÇÃO: Foram incluídos estudos experimentais e ensaios clínicos randomizados que avaliaram os efeitos dos recursos eletrofísicos na osteoporose. RECOMPILAÇÃO E ANÁLISE DE DADOS: Dois revisores selecionaram independentemente os estudos, avaliaram sua qualidade metodológica dos estudos e coletaram os dados. RESULTADOS: Todos os recursos eletrofísicos citados neste artigo se mostraram eficazes na estimulação do metabolismo ósseo. No entanto, a grande maioria dos estudos realizados evidenciam esses efeitos através de estudos in vitro e estudos experimentais com cobaias. Cabe ressaltar que trabalhos como esses são raros em seres humanos. Baseado nos achados desta revisão pode ser sugerido que os recursos eletrofísicios como o laser terapêutico, o ultrassom, campos eletromagnéticos e plataformas vibratórias são recursos que tem um potencial osteogênico entretanto mais estudos são necessários para definir os efeitos dos mesmos em humanos, bem como, protocolos mais eficazes de tratamento. CONCLUSÃO: A partir deste levantamento bibliográfico, fica evidente que os recursos eletrofísicos apresentam um grande potencial osteogênico, porém, a maior parte dos estudos é in vitro. São necessários mais estudos in vivo, definindo, assim, melhores parâmetros e doses, para que sejam utilizados no tratamento da osteoporose.

OBJECTIVE: The aim of this article was to provide a literature review regarding the impact of the main eletrophysical resources used on the acceleration of bone metabolism and on the osteoporosis treatment. DEFINITION: The OMS defines osteoporosis as a Sistemic esqueletical disease characterized for diminished bone mass and for deterioration of the bone mass microarchitecture, increasing the bone fragility and susceptibility to fracture. Many drug or non-drug treatments are being developed as an attempt to increase the bone mass, and prevent osteoporosis. Within this context, the eletrophysical resources is having a prominence paper, as a resource which presents a osteogenic potencial, capable of stimulating the proliferation of osteoblasts and biomodulate the bone metabolism. RESEARCH STRATEGIES: The data base consulted were: The Cochrane Library, MEDLINE, Embase, LILACS, SciELO, references of indentified articles and contact with laser's especialists, between 1983 and 2009. SELECTION CRITERIA: Were included experimental study and randomized clinical tests on the effects of eletrophysical resources on osteoporosis. RECOMPILATION AND DATA ANALISIS: Two reviewers independently selected the studies, assessed their methodological quality and collected the data. RESULTS: All the eletrophysical resources quoted on this article were effective in stimulation of bone metabolism. However, most of the studies show these effects through in vitro studies and experimental studies with animals. It is important to say that experiments like these are rare in human beings. Based on the findings of this review, it may be suggested that the eletrophysical resources like lasertherapy, ultra-sound, electromagnetic fields and vibration are resources that has osteogenic potencial, but more studies are needed to define the effects of it in humans, as well as more effective treatment protocols. CONCLUSION: With this literature review it is clear that eletrophysical resources have high osteogenic potential, but most of the studies are in vitro. It is needed more studies in vivo, defining therefore, better parameters and doses to be used in the treatment of osteoporosis.

Muitos estudos demonstram que programas de atividade física são eficazes para estimular o metabolismo ósseo, sendo utilizados como uma modalidade terapêutica em caso de perda óssea devido a osteoporose. Entretanto, vários pontos relacionados a intensidade e freqüência ideal para do exercício físico ainda não estão esclarecidos. Com isso, o objetivo deste estudo foi determinar os efeitos de um programa de exercícios físicos de alta intensidade na morfometria, na força óssea e no conteúdo mineral do fêmur de ratas osteopênicas. Foram utilizadas 40 ratas, distribuídas em 4 grupos: grupo intacto sedentário (SS); grupo osteopênico sedentário (OS); grupo intacto treinamento (ST) e grupo osteopênico treinamento (OT). O programa de exercício foi iniciado 8 semanas após a ovariectomia e foi realizado 3 vezes por semana, durante 8 semanas. Cada sessão foi constituída por 4 séries de 10 saltos cada. Após a eutanásia dos animais, os fêmures foram retirados e processados para as analises. RESULTADOS: os animais osteopênicos sedentários demonstraram uma diminuição da força óssea e uma diminuição dos pesos ósseos, da densidade óssea e do conteúdo de cálcio. As ratas osteopênicas exercitadas mostraram maiores valores na avaliação dos pesos ósseos, da força óssea, da densidade óssea e do conteúdo mineral, evidenciando o efeito positivo deste protocolo no metabolismo ósseo. Os resultados deste estudo indicam que a intensidade e a duração do programa de exercícios utilizado foi eficaz para produzir modificações nas propriedades geométricas e na forca óssea, nos fêmures das ratas osteopênicas, o que contribuiu para reverter as perdas ósseas após a ovariectomia.

BACKGROUND: Many studies have shown that physical exercises are able to stimulate bone formation and increase bone mass, constituting a therapeutic modality for the treatment of 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 were 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 an evaluation of physical properties, 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 has stimulatory effects on osteopenic rats' femora. It seems that the intensity and duration of the used protocol produced bone structural adaptations, which contributed to revert bone loss due to ovariectomy.