Bone callus formation is highly disrupted by dietary restriction in growing rats sustaining a femoral fracture

Purpose:To evaluate the effects of food restriction on fracture healing in growing rats.Methods:Sixty-eight male Wistar rats were assigned to two groups: (1) Control and (2) Dietary restriction. After weaning the dietary restricted animals were fed ad libitum for 42 days with 50% of the standard chow ingested by the control group. Subsequently, the animals underwent bone fracture at the diaphysis of the right femur, followed by surgical stabilization of bone fragments. On days 14 and 28 post-fracture, the rats were euthanized, and the fractured femurs were dissected, the callus was analyzed by dual-energy X-ray absorptiometry, micro-computed tomography, histomorphometry, mechanical tests, and gene expression.Results:Dietary restriction decreased body mass gain and resulted in several phenotypic changes at the bone callus (a delay in cell proliferation and differentiation, lower rate of newly formed bone and collagen deposition, reductions in bone callus density and size, decrease in tridimensional callus volume, deterioration in microstructure, and reduction in bone callus strength), together with the downregulated expression of osteoblast-related genes.Conclusion:Dietary restriction had detrimental effects on osseous healing, with a healing delay and a lower quality of bone callus formation.(AU)

Nandrolone decanoate appears to increase bone callus formation in young adult rats after a complete femoral fracture

Purpose: To evaluate the influence of nandrolone decanoate on fracture healing and bone quality in normal rats. Methods: Male rats were assigned to four groups (n=28/group): Control group consisting of animals without any intervention, Nandrolone decanoate (DN) group consisting of animals that received intramuscular injection of nandrolone decanoate, Fracture group consisting of animals with a fracture at the mid-diaphysis of the femur, and Fracture and nandrolone decanoate group consisting of animals with a femur fracture and treatment with nandrolone decanoate. Fractures were created at the mid-diaphysis of the right femur by a blunt trauma and internally fixed using an intramedullary steel wire. The DN was injected intramuscularly twice per week (10 mg/kg of body mass). The femurs were measured and evaluated by densitometry and mechanical resistance after animal euthanasia. The newly formed bone and collagen type I levels were quantified in the callus. Results: The treated animals had longer femurs after 28 days. The quality of the intact bone was not significantly different between groups. The bone callus did show a larger mass in the treated rats. Conclusion: The administration of nandrolone decanoate did not affect the quality of the intact bone, but might have enhanced the bone callus formation.(AU)

Bone healing after biodegradable mini-plate fixation

PURPOSE:To compare bone healing in mandibular vertical body osteotomies (MVBO) after fixation with a resorbable 2.0mm-profile fixation system in the first and third postoperative months in rabbits.METHODS:Twenty hemimandibles of ten rabbits were divided into two groups according to duration of resorbable fixation-one or three months. The MVBOs were performed and one four-hole, resorbable, 2.0mm mini-plate fixation system was used on each side. The computed tomography (CT) scans, scanning electron microscopy (SEM), and histomorphometric outcomes of groups I and II were compared.RESULTS:Significant differences were found between the one- and three- month assessments in terms of newly formed bone ratio values (p<0.05). There was more new bone formation at the third month on both the CT and histomorphometric examinations. A better adaptation of the bone tissues to the resorbable mini-plate and screws was observed on SEM at three months.CONCLUSION:The resorbable mini-plates provided a fixation stable enough to allow immediate oral alimentation and callus formation in both groups.(AU)

Utilização de métodos não invasivos de imagem para avaliação da regeneração óssea em falhas ósseas induzidas experimentalmente em III/IV metacarpianos de ovinos / Use of non-invasive imaging methods for evaluation of bone regeneration in bone defects induced experimentally in III/IV metacarpus of sheep

Background: The events involved in the process of bone regeneration of fractures are influenced by physiological factors and a number of techniques can be used to assess bone tissue. The radiographic examination (ER) is often used in clinical practice to evaluate the consolidation process. Ultrasound (US) allows evaluation of the fibrous callus, present in early stages of consolidation. Thermograph is method of evaluation for image, which allows you to estimate activity of some tissue. The aim of this study was to evaluate bone fill process, during 60 days, through thermograph, ultrasound and x-ray of ostectomy induced experimentally.Materials, Methods & Results: Six female Santa Inês breed ewes were subjected to unicortical ostectomy of seven millimeters in diameter, in the proximal region of the dorsum-medial surface of III/IV metacarpal, chosen randomly. The animals were submitted to radiographic evaluations, ultrasound and thermograph, prior to the surgery and during 60 days, in between 7, 14, 21, 28, 35, 42, 49 and 56 days postoperatively. The radiographic images were evaluated by examiners “blind” (two radiologists and two sonographers), that didnt know the postoperative day that the image member evaluated. The thermograph images were processed in program for measuring the average temperature in the region of bone gap, over time. The Friedman test was applied to assess the progression of the studied variables over the period of the experiment. Over the period of 60 days it was possible to observe the difference of fault, fill scores by radiographic examination and ultrasound examination (P < 0.001). The Wilcoxon test was applied to observer the differences in scores between the examiners over the period of the experiment. Statistically significant difference was observed between the evaluators of radiographic images from day 14, not being observed between by the evaluators of ultrasound images.[...](AU)

Whole-body vibration improves fracture healing and bone quality in rats with ovariectomy-induced osteoporosis

To investigate the effect of vibration therapy on the bone callus of fractured femurs and the bone quality of intact femurs in ovariectomized rats. METHODS: Fifty-six rats aged seven weeks were divided into four groups: control with femoral fracture (CON, n=14), ovariectomized with femoral fracture (OVX, n=14), control with femoral fracture plus vibration therapy (CON+VT, n=14), and ovariectomized with femoral fracture plus vibration therapy (OVX+VT, n=14). Three months after ovariectomy or sham surgery, a complete fracture was produced at the femoral mid-diaphysis and stabilized with a 1-mm-diameter intramedullary Kirschner wire. X-rays confirmed the fracture alignment and fixation. Three days later, the VT groups underwent vibration therapy (1 mm, 60 Hz for 20 minutes, three times per week for 14 or 28 days). The bone and callus quality were assessed by densitometry, three-dimensional microstructure, and mechanical test. RESULTS : Ovariectomized rats exhibited a substantial loss of bone mass and severe impairment in bone microarchitecture, both in the non-fractured femur and the bone callus. Whole-body vibration therapy exerted an important role in ameliorating the bone and fracture callus parameters in the osteoporotic bone. CONCLUSION: Vibration therapy improved bone quality and the quality of the fracture bone callus in ovariectomized rats.(AU)

Utilização de métodos não invasivos de imagem para avaliação da regeneração óssea em falhas ósseas induzidas experimentalmente em III/IV metacarpianos de ovinos / Use of non-invasive imaging methods for evaluation of bone regeneration in bone defects induced experimentally in III/IV metacarpus of sheep

Background: The events involved in the process of bone regeneration of fractures are influenced by physiological factors and a number of techniques can be used to assess bone tissue. The radiographic examination (ER) is often used in clinical practice to evaluate the consolidation process. Ultrasound (US) allows evaluation of the fibrous callus, present in early stages of consolidation. Thermograph is method of evaluation for image, which allows you to estimate activity of some tissue. The aim of this study was to evaluate bone fill process, during 60 days, through thermograph, ultrasound and x-ray of ostectomy induced experimentally.Materials, Methods & Results: Six female Santa Inês breed ewes were subjected to unicortical ostectomy of seven millimeters in diameter, in the proximal region of the dorsum-medial surface of III/IV metacarpal, chosen randomly. The animals were submitted to radiographic evaluations, ultrasound and thermograph, prior to the surgery and during 60 days, in between 7, 14, 21, 28, 35, 42, 49 and 56 days postoperatively. The radiographic images were evaluated by examiners “blind” (two radiologists and two sonographers), that didn’t know the postoperative day that the image member evaluated. The thermograph images were processed in program for measuring the average temperature in the region of bone gap, over time. The Friedman test was applied to assess the progression of the studied variables over the period of the experiment. Over the period of 60 days it was possible to observe the difference of fault, fill scores by radiographic examination and ultrasound examination (P < 0.001). The Wilcoxon test was applied to observer the differences in scores between the examiners over the period of the experiment. Statistically significant difference was observed between the evaluators of radiographic images from day 14, not being observed between by the evaluators of ultrasound images.[...]

Lithothamnium calcareum no tratamento de osteotomia experimental em coelhos (Oryctolagus cuniculus) / Lithothamnium calcareum in the treatment of experimental osteotomy in rabbits (Oryctolagus cuniculus)

Avaliaram-se os efeitos da suplementação com Lithothamnium calcareum na consolidação de osteotomia experimental em coelhos, por meio de exames radiográfico e histológico. Utilizaram-se 10 coelhos machos da raça Nova Zelândia, de quatro a cinco meses de idade, com massa corporal média de 2,5kg, os quais foram submetidos à osteotomia do terço médio da tíbia direita e à fixação interna com dois pinos intramedulares. Os coelhos foram distribuídos aleatoriamente em dois grupos experimentais (A e B) com cinco animais cada. O grupo A recebeu diariamente dieta contendo 0,75% de L. calcareum, e o grupo B constituiu o controle sem tratamento adicional à fixação da osteotomia. A evolução clínica ocorreu sem intercorrências. As radiografias foram realizadas antes do estudo e em intervalos de 15 dias até o final do experimento, e a histologia foi realizada aos 60 dias. As avaliações radiográficas permitiram acompanhar a evolução do processo de consolidação que ocorreu em todos os casos. Histologicamente, verificou-se consolidação completa em todos os animais do grupo B (controle) e em 75% do grupo A. Dos resultados pode-se concluir que, embora tenha ocorrido a consolidação clínica e a radiográfica aos 60 dias em todos os casos, histologicamente o grupo-controle (B) foi melhor, mostrando que o organismo sadio não necessita de estímulo para o processo de reparação óssea. Novas pesquisas devem ser realizadas para avaliar o efeito da suplementação mineral em animais portadores de deficiências nutricionais.(AU)

The purpose of this work was to evaluate Lithothamnium calcareum suplementation in the consolidation of experimental osteotomy in rabbits, through radiographic and histology examinations. Ten male New Zealand white rabbits, 4-5 months of age with an average body mass of 2.5kg, had surgically induced mid-tibial osteotomies, fixed with two intramedullary pins. The animals were randomly divided into two experimental groups (A and B). Group A received a diet containing 0.75% of L. calcareum, and group B served as control without further treatment of the osteotomy fixation. Radiographs were done every 15 days until the end of the experiment and histology was performed at day 60. Radiographs show consolidation in all cases. Histologically there was bone consolidation in all animals in group B (control), and 75% in group A. From the results we can conclude that, although there was clinical and radiographic bone consolidation in all cases after 60 days, the control group proved to be better histologically, showing that a healthy organism needs no aid to repair bone. Further research should be conducted to assess the effects of mineral supplementation on animals with nutritional deficiencies.(AU)

Implante de biomateriais e a consolidação óssea em cadelas submetidas à ovariossalpingo-histerectomia / Influence of biomaterials on the bony consolidation in spayed female dogs

Avaliou-se a hidroxiapatita com alandronato e hidroxiapatita com colágeno na aceleração da consolidação óssea do rádio de cadelas adultas submetidas à ovariossalpingo-histerectomia (OSH). Utilizaram-se 14 cadelas adultas, distribuídas aleatoriamente em dois grupos: grupo-controle e grupo OSH (submetidas à OSH). Quatro meses após a OSH, as cadelas dos dois grupos foram submetidas à cirurgia para produção de uma falha óssea de 4mm de diâmetro nos terços distal e proximal do rádio. No terço distal do membro direito, foi utilizada a hidroxiapatita com alandronato e, no membro esquerdo, a hidroxiapatita com colágeno; no terço proximal, não se utilizou nenhum biomaterial. Houve retardo na consolidação das falhas ósseas nas cadelas submetidas à OSH comparadas com as não submetidas. A hidroxiapatita com alandronato acelerou o processo de reparação e, em todos os animais dos dois grupos, a densidade óssea foi significativamente maior no terço distal onde foi implantada. Os dois biomateriais apresentaram biocompatibilidade, constatada pela ausência de reação inflamatória ou outra reação indesejável.(AU)

The hydroxyapatite with alendronate and hydroxyapatite with collagen were evaluated in the acceleration of the bony consolidation of adult spayed bitch radius. For that, 14 adult bitches were distributed in two groups (control and spayed). Four months after ovariohysterectomy, the groups were submitted to the surgery for production of a 4mm diameter bony flaw in the distal and proximal third regions of the radius. In the distal region of the right thoracic limb, hydroxyapatite with alendronate was used. In the distal region of the left thoracic limb, hydroxyapatite with collagen was used. Any biomaterial was used in proximal part of the limb. There was a retard in bony flaws consolidation in the spayed bitches. Hydroxyapatite with alendronate showed better result, since the place it was implanted considerably increased the bony formation. Both biomaterials presented biocompatibility, verified by the absence of inflammatory reaction or other undesirable reaction.(AU)

Avaliação radiográfica, densitométrica e histológica do uso de perfurações ósseas para o estímulo de consolidação de fraturas do terço distal do rádio de cães / Radiographic, densitometric and histological evaluation of the use of bone perforations on fracture consolidation of distal third of radius from dogs

Objetivando estimular o processo de formação do calo ósseo do terço distal do rádio de cães de pequeno porte, foram utilizados 24 animais srd, adultos, de ambos os sexos. Os cães, separados em dois grupos experimentais de 12 animais denominados de controle e tratado foram divididos em 4 momentos (m1= 15 dias, m2= 30 dias, m3= 45 dias e m4= 60 dias), e submetidos a fraturas cirúrgicas. no grupo tratado, foram realizadas perfurações ósseas nos bordos do foco da fratura, no sentido crânio-caudal e médio-lateral. No final de cada momento, os animais controles e tratados foram avaliados radiograficamente, histologicamente e a densidade mineral óssea (dmo) determinada no local da fratura. Na avaliação radiográfica do grupo tratado com 15 e 30 dias foi verificado o processo de reparação óssea mais intenso do que no grupo controle. Nos momentos m3 e m4, não se observaram diferenças no processo de reparação entre os dois grupos. Os valores da dmo foram maiores nos animais tratados. o estudo histológico revelou aos 15 e 30 dias, hiperplasia de condrócitos, e inicio de ossificação endocondral nos membros perfurados; o grupo controle mostrou tecido conjuntivo de sustentação e irúcio de hiperplasia de condrócitos. Nos m3 e m4 do grupo tratado, se verificaram formação e remodelação de calo periosteal em fases mais avançadas quando comparados ao grupo controle. conclui-se que o uso de perfurações melhora o suprimento de fluxo sangüíneo e a ativação de células osteogênicas no local de fratura, estimulando o início do processo de consolidação da fratura.(AU)

To stimulate the bone callus development process from distal third of radius, 24 adult mongrel dogs used were from both sexes. These dogs were separated in two experimental groups of 12 animals each, named control and treated, divided in 4 moments (M1=15 days; M2=30 days; M3=45 days; M4=60 days), who underwent were performed surgical fractures. In treated group, it was performed bone perforations on proximal and distal edges, craniolateral and mediolateral to the fracture site. At the end of each moment, control and treated animals were evaluated by radiography, histology, and bone mineral densitometry (BMD) was determined on fracture site. According to the radiographic data of treated dogs, it was verified on days 15 and 30 more intense bone regeneration than control group. During M3 and M4, it wasn't detected any difference in bone reparation process between control and treated groups. In densitometric study, BMD values were greater in treated animaIs than in control dogs. Histological studies revealed at 15 and 30 days chondrocyte hyperplasia and initial endochondral ossification on drilled limbs; control group showed sustainment connective tissue and initial chondrocyte hiperplasia. At M3 and M4 of the treated group, were verified development and remodeling of periosteal callus in more advanced phases when comparing with limbs from control group. It can be concluded that using perforations enhances blood flow supply and activation of osteogenic cells on fracture site, stimulating the beginning of fracture consolidation process.(AU)