Morphometric evaluation of condylar cartilage of growing rats in response to mandibular retractive forces

INTRODUCTION: The mandibular condylar surface is made up of four layers, i.e., an external layer composed of dense connective tissue, followed by a layer of undifferentiated cells, hyaline cartilage and bone. Few studies have demonstrated the behavior of the condylar cartilage when the mandible is positioned posteriorly, as in treatments for correcting functional Class III malocclusion. OBJECTIVE: The aim of this study was to assess the morphologic and histological aspects of rat condyles in response to posterior positioning of the mandible. METHODS: Thirty five-week-old male Wistar rats were selected and randomly divided into two groups: A control group (C) and an experimental group (E) which received devices for inducing mandibular retrusion. The animals were euthanized at time intervals of 7, 21 and 30 days after the experiment had began. For histological analysis, total condylar thickness was measured, including the proliferative, hyaline and hypertrophic layers, as well as each layer separately, totaling 30 measurements for each parameter of each animal. RESULTS: The greatest difference in cartilage thickness was observed in 21 days, although different levels were observed in the other periods. Group E showed an increase of 39.46% in the total layer, reflected by increases in the thickness of the hypertrophic (42.24%), hyaline (46.92%) and proliferative (17.70%) layers. CONCLUSIONS: Posteriorly repositioning the mandible produced a series of histological and morphological responses in the condyle, suggesting condylar and mandibular adaptation in rats.

INTRODUÇÃO: a superfície do côndilo da mandíbula é constituída por quatro camadas: uma externa (constituída de tecido conjuntivo denso), seguida pela camada de células indiferenciadas, cartilagem hialina e osso. Poucos estudos demonstraram o comportamento da cartilagem condilar quando a mandíbula é posicionada posteriormente, como na terapia para correção de Classe III funcional. OBJETIVO: o objetivo desse trabalho foi avaliar os aspectos morfológicos e histológicos do côndilo de ratos, em resposta ao posicionamento posterior da mandíbula. MÉTODOS: foram selecionados 30 ratos Wistar, machos, com cinco semanas de vida, aleatoriamente divididos em dois grupos: grupo controle (GC) e grupo experimental (GE), que recebeu dispositivos para induzir a retrusão mandibular. Os animais foram sacrificados após 7, 21 e 30 dias de experimento. Para a análise histológica, foi realizada a mensuração da espessura condilar total, incluindo as camadas proliferativa, seriada e hipertrófica, assim como cada camada separadamente, totalizando 30 medições para cada parâmetro, de cada animal. RESULTADOS: a maior diferença na espessura da cartilagem foi observada em 21 dias, apesar de serem verificados níveis diferentes nos demais períodos. Em GE, foi possível observar um aumento de 39,46% na camada total, representado pelo aumento na espessura das camadas hipertrófica (42,24%), seriada (46,92%) e proliferativa (17,70%). CONCLUSÕES: o reposicionamento posterior da mandíbula produziu uma série de respostas histológicas e morfológicas no côndilo, e sugerem a ocorrência de uma adaptação condilar e mandibular em ratos.

In vitro effects of caffeine in growth cartilage of rats / Efeitos in vitro da cafeína na cartilagem de crescimento de ratos

OBJETIVO: Avaliar os efeitos in vitro da cafeína na proliferação, apoptose e expressão de transcriptos gênicos de diferenciação condrogênica na cartilagem de crescimento.MÉTODO: As epífises cartilaginosas de fêmures de ratos neonatos foram divididas em dois subgrupos: os tratados com cafeína e o grupo controle, ambos observados nos tempos de 0, 7, 14 e 21 dias. As epífises cartilaginosas de fêmures de cada subgrupo e de cada tempo foram submetidas à histomorfometria, análise imunoistoquímica, técnica de túnel e RT-PCR em tempo real.RESULTADO: A diminuição da atividade proliferativa e o aumento de condroblastos em apoptose aos 21 dias foram encontrados em ambos os subgrupos. Entretanto a diminuição da proliferação celular causada pela cafeína foi menor quando comparada ao grupo controle e aumentou significativamente a expressão de transcriptos gênicos para diferenciação condrogênica, representada pelo SOX-9 e pelo RUNX-2. Entretanto o cultivo in vitro com cafeína demostrou efeitos antagônicos: apesar dos efeitos positivos na proliferação e diferenciação de condroblatos, cafeína aumentou a apoptose, caracterizada pelo aumento da expressão de caspase-3 e do numero de células em apoptose (p< 0.05).CONCLUSÃO: A cafeína apresenta efeitos antagônicos in vitro na cartilagem em crescimento, aumentando a proliferação, diferenciação e apoptose celular. Estudo experimental.

OBJECTIVE: To evaluate the in vitro effetcs of caffeine on proliferation, apoptosis and gene transcripts expression of chondrogenic differentiation in growth cartilage.METHODS: The cartilaginous epiphyses of femurs of newborn rats, which were divided into two subgroups: treated with caffeine and control group, both observed over the time periods of 0, 7, 14 and 21 days. The cartilaginous epiphyses of femurs of each subgroup and each time span were subjected to histomorphometric, immunohistochemical analysis, Tunel technique and RT-PCR in real time.RESULTS: The decrease in proliferative activity and the increase of apoptotic chondroblasts at 21 days were found regardless of the subgroup. However, the decrease in cell proliferation caused by caffeine was lower than in the control group and significantly increased the expression of gene transcripts for chondrogenic differentiation, represented by SOX-9 and RUNX-2. However, the in vitro culture with caffeine revealed antagonistic effects: despite the positive effect on chondroblasts proliferation and differentiation, caffeine increased apoptosis, characterized by increased expression of caspase 3 and of the number of cells undergoing apoptosis (p<0.05).CONCLUSION: Caffeine presents antagonistic effects in vitro on growth cartilage, increasing the proliferation, differentiation and cell apoptosis. Experimental Study.

Preventive role of zinc chloride against toxicity of ciprofloxacin on the growing cartilage of wistar albino rat litter

To assess the preventive role of zinc chloride on toxicity of ciprofloxacin administration in wistar albino rat litter. It was a Prospective experimental study. The study was carried out in the department of Anatomy, Basic Medical Sciences Institute, Jinnah Postgraduate Medical Centre, Karachi, Pakistan during March 2002 to February 2003 one year study. Ciprofloxacin and zinc chloride were administered to newly born albino rat litters separately and simultaneously at a dose of 20 mg/kg body weight and 1200 micro g/Kg body weight respectively, intraperitonealy twice daily from 1-14 day after birth. The animals were sacrificed by deep ether anaesthesia. The fore and hind limbs were dis-articulated from the axial skeleton, soft tissue was removed and bones were fixed in 10% buffered formalin. Decalcification was done in 10% nitric acid and 10% formic acid changes. After paraplast embedding, 4 micro m thick longitudinal sections of proximal and distal ends of long bones were cut by a rotary microtome. Routine staining with haemotoxylin and eosin was performed. Histomorphometery was done to measure the thickness of epiphyseal cartilage and was compared with similar values of the control animals. The results were statistically analyzed to evaluate the significance. Our study revealed that ciprofloxacin administration in new born albino rat litter decreased the width of epiphyseal growth plate cartilage by 13.7 +/- 0.42 micro m, 10.43% in humerus and 6.6 +/- 1.2 micro m 4.72% in femur as compared to control, whereas, simultaneous zinc chloride administration restricted the decrease to 1.27 micro m +/- SD in humerus and 2.05 micro m +/- SD in femur. Simultanous zinc chloride administration minimized the epiphseal cartilage damage induced by ciprofloxacin in Wistar albino rat litter

Factores que regulan la morfogénesis y el crecimiento mandibular humano / Factors that regulate the morphogenesis and human mandibular growth

La regulación del crecimiento y desarrollo cráneo-facial está controlada por una serie de interacciones celulares y con la matriz extracelular que estimulan los procesos de proliferación y diferenciación. De fundamental importancia es la cresta neural, una población de células especializadas de células progenitoras que generan los huesos, cartílagos y tejido conectivo de la región. La mandíbula se forma por osificación membranosa en el mesénquima del primer arco faríngeo, pero desarrolla cartílagos secundarios como centros de crecimiento en el cóndilo, en el proceso coronoídeo, en el ángulo mandibular y en la sutura intermaxilar (sínfisis). Estos cartílagos difieren en su origen, su estructura histológica y su respuesta a factores hormonales, metabólicos y mecánicos con respecto a los cartílagos de los huesos largos. Debido a que las células proliferativas son mesenquimáticas y no cartilaginosas, los mecanismos celulares y moleculares que regulan el crecimiento en los cartílagos secundarios, son todavía muy poco conocidos. Los productos génicos BMP (proteina morfogenética de hueso), Ihh (Indian hedgehog), FGF (factor de crecimiento de fibroblastos), Sox-9 y VEGF (factor de crecimiento vascular endotelial) son de gran importancia en el crecimiento mandibular. Este trabajo resume la información reciente acerca de los factores de crecimiento y factores de transcripción, potenciales reguladores del proceso de osificación membranosa y del crecimiento de los cartílagos secundarios de la mandíbula.

Regulation of growth and craniofacial development is controlled by the interactions of cells with each other and with the extracellular environment through signal transduction pathways that control the differentiation process by stimulating proliferation or causing cell death. Of fundamental importance to mandibular development is the neural crest, a specialized population of stem and progenitor cells which generate the bone, cartilage and conjunctive tissue of the first branchial arch. The mandible arises by intramembranous ossification, but develops secondary cartilages as growth centers. Secondary cartilages of the mandible arise in the condylar process, in the coronoid process, angular process of the mandible, and in the intermandibular suture (mental symphysis). These are different, not only in their origins, but in their histologic organization and in their response to hormonal and mechanical factors with articular cartilages of long bones. Because the cells that divide to effect growth and adaptation in these cartilages are of perichondrial/periosteal rather than chondrogenic origin, the cellular and molecular mechanisms that regulate their growth are only beginning to be understood. The main differences of secondary cartilages from cartilages of the limbs and cranial base are, that condylar condroblasts arise from undifferentiated conjuntive cells and the appearance of vascular canals that cross cartilage perpendicularly and connect with the ossification zone. Collagen type I seems to be more important in this process than collagen type II. BMP signaling maintains regulatory roles in skeletons and skeletal growth. Indian hedgehog, Sox-9, fibroblastic growth factor (FGF) and vascular endothelial growth factor (VEGF), are also important in mandibular growth. This article summarizes information regarding growth factors and transcription proteins that are potential growth regulators in these secondary cartilages.

Effects of glucosamine on the tibial epiphyseal disk of ovariectomized rats: morphologic and morphometric analysis

OBJECTIVE: The aim of this study was to analyze the effect of glucosamine sulfate on the tibial epiphyseal disk of the ovariectomized rats. METHODS: After ovariectomy (OVx), 28 female rats were randomly divided into 4 experimental groups with 7 animals each, treated as follows: OVx 21 - vehicle (NaCl 0.9 percent) 0.5 mL/day) for 21 days; OVx GS21 - 230 mg/kg/day glucosamine sulphate for 21 days; OVx 45 - treated with NaCl 0.9 percent as above for 45 days; and OVx - GS45230 mg/kg/day glucosamine sulphate for 45 days. Seven intact animals in the proestrous phase were used as controls (CG). Upon treatment completion, the animals were sacrificed and the left knee joint was dissected and prepared for histological analysis. RESULTS: The percentage of remaining cartilage in new bone of the CG; that found in THE OVx GS45 group was significantly less than that of the OVx 21, OVx GS21, and OVx 45 groups. The percentage of trabecular bone in proestrous animals was the highest. The OVx GS45 group showed higher values compared with the other ovariectomized groups. These results were paralleled by the findings regarding the cells of the proliferative zone, since the CG had the highest values, and the values of the OVx GS45 group were greater than those of the OVx 21, OVx GS21, and OVx 45 groups. CONCLUSION: Our studies suggested that glucosamine may stimulate tibial cartilage and bone growth after ovariectomy in rats.

OBJETIVO: O alvo deste estudo foi analisar o efeito do sulfato de glicosamina no disco epifisário da tíbia em ratas ooforectomizadas. MÉTODOS: Após a ooforectomia (OVx), 28 ratas foram aleatoriamente divididas em 4 grupos experimentais de 7 animais cada, tratados da seguinte maneira: OVx 21 - veículo (0,5ml de NaCl 0.9 por cento ip uma vez ao dia) por 21 dias; OVx GS21 230 - mg/kg peso corporal por dia de sulfato de glicosamina, 21 dias; OVx 45 - tratados com NaCl 0.9 por cento igual ao grupo OVx 21, por 45 dias; e OVx GS45 - 230 mg/kg peso corporal por dia com sulfato de glicosamina, 45 dias. Sete animais intactos, na fase de proestro, foram usados como controle (CG). Ao completar o tratamento, os animais foram sacrificados e a articulação do joelho esquerdo foi dissecada e preparada para análise histológica. RESULTADOS: A porcentagem de cartilagem remanescente no novo osso do CG foi a menor. Os achados no grupo OVx GS45 foi significantemente menor do que no grupo OVx 21, OVx GS21 e OVx 45. A porcentagem de osso trabecular nos animais em pró-estro foi a maior. O grupo OVx GS45 mostrou valores maiores em relação aos outros grupos ooforectomizados. Esses resultados foram correspondentes aos achados em relação às células da zona proliferativa, desde que o CG teve os maiores valores e os valores do grupo OVx GS45 foram superiores aos dos grupos OVx 21, OVx GS21 e OVx 45. CONCLUSÃO: Nossos estudos sugerem que a glicosamina pode estimular o crescimento da cartilagem e do osso tibial após a ooforectomia em ratas.

Effect of Ciprofloxacin on growing cartilage in albino Rat pups

Administration of quinolone therapy is controversial during growing age as stated by earlier worker. The flroquinolones are currently not indicated for young children, because of arthropathy and adverse effect on growing cartilage shown by studies. However the effects of ciprofloxacin on epiphyseal growth plate has remained undocumented. This study is therefore, undertaken to determine the risk of ciprofloxacin administration an growing cartilage by prospective experimental animal study model using Wistar albino rat pups. Ciprofloxacin was administered to newly born Wistar albino rat pups with a doze of 20mg/kg body weight intraperitonealy twice a day from day-1 to day-14 after birth. The animals were sacrificed by deep ether anesthesia. The limbs were disarticulated from axial skeleton, soft tissue was removed. The intact bone mean length in millimeter of right and left humerus and femur was measured with the help of electronic vernier caliper and bones were fixed in 10% buffered farmalin. Decalcification was done in 10% nitric acid and 10% formic acid changes. After paraplast embeding, 4 mm thick longitudinal sections of the proximal long bones were cut by a rotary microtome. Routine staining with haemotoxylin and eosin was performed. Histomorphometry was done measuring the thickness of epiphyseal cartilage and was compared with similar value of control animals. The results were statistically analysed to find out the significance. The ciprofloxacin induces a mordanting effect as abviated by increased basophilia. Our study reveales that cirprofloxacin administration in the newly born pups decreased the width of epiphyseal growth plate cartilage by 10.43% in humerus and 4.72% in femur as compared to the growth of control cartilage. The decrease in the width was brought about mainly by the reduced count of the proliferative cells in the proliferative zone and the diminuation in the average size of the hypertrophic condryocytes in the hypertrophic zone. The reserve zone has become markedly reduced in thickness. The ciprofloxacin post-natal administration effected growth plate retardation by inhibiting the mitosis in the proliferative zone and also effected the mean length of humora and femora leading to reduction in limb length of rat pups

Avaliação do peso de cartilagem desidratada e hidratada / Weight assessment of dehydrated and hydrated cartilage

A cartilagem de banco pode ser utilizada para tratamento cirúrgico do lagoftalmia, reconstrução nasal e auricular, reconstrução do assoalho da órbita e cirurgia do mento. Este trabalho tem como objetivo avaliar o peso da cartilagem desidratada e hidratada e a variação do peso após a implantação de ambas as cartilagens em dorso de ratos. Foram utilizados 10 ratos Norvergicus submetidos a dois implantes de cartilagens conservadas em álcool etílico a 70, obtidas de cadá- veres. Uma cartilagem a ser implantada permaneceu em solução com a álcool 70 e outra, em solução fisiológica (NaCl 0,9), por 24 h antes do procedimento cirúrgico. O peso médio inicial era de 0,5 g e após a hidratação passou a pesar 1,2 g em média. As cartilagens foram então implantadas no dorso dos ratos e após 8 dias retiradas e pesadas novamente para avaliação estatística do ganho de peso.

The cartilage bank can be used for lagoftalmia surgical treatment, nose and ear reconstruction and low jaw surgery. This study has the objective of evaluating the weight of hydrated and dehydrate cartilage and the variation of weight after the implementation of both cartilages on the back of mice. Ten Norvergicus mice were submitted to the implanting of cartilages obtained from corpses and that were kept in alcohol etilic 70. One of the cartilage to be implanted was kept in a solution with alcohol 70 and the other one in SF (NaCl 0,9) for 24h before the surgery procedure. The medium initial weight was 0.5g and after the hydratation it medium weighted 1.2g. The cartilages were then implanted on the back of mice and taken out 8 days later and weighted again for statistic evaluation on weight increase.

An overview of cartilage tissue engineering

Articular cartilage regeneration refers to the formation of new tissue that is indistinguishable from the native articular cartilage with respect to zonal organization, biochemical composition, and mechanical properties. Due to a limited capacity to repair cartilage, scar tissue frequently has a poorly organized structure and lacks the functional characteristics of normal cartilage. The degree of success to date achieved using a purely cell- or biological-based approach has been modest. Potentially the development of a hybrid strategy, whereby, chondrocytes or chondrogenic stem cells are combined with a matrix, making cartilage in vitro, which is then subsequently transplanted, offers a route towards a new successful treatment modality. The success of this approach depends upon the material being biocompatible, processable into a suitable three-dimensional structure and eventually biodegradable without harmful effects. In addition, the material should have a sufficient porosity to facilitate high cell loading and tissue ingrowth, and it should be able to support cell proliferation, differentiation, and function. The cell-polymer-bioreactor system provides a basis for studying the structural and functional properties of the cartilaginous matrix during its development, because tissue concentrations of glycosaminoglycan and collagen can be modulated by altering the conditions of tissue cultivation.

Sindrome de Eagle Traumático / Traumatic Eagle's syndrome

La presente comunicación es a propósito de un caso de fractura de la apófisis estiloides del temporal o Síndrome de Eagle traumático. Efectuamos una revisión de la literatura sobre el tema, y describimos sus diferentes etiologías y su patogenia con especial referencia a la embriología y a la osificación anormal de la cadena estilohioidea, así como al diagnóstico diferencial y al tratamiento médico y quirúrgico. Nuestro paciente tuvo una remisión total de la sintomatología con tratamiento médico