Effects of fluoride on skeletal development of zebrafish and its correlation with OPG/RANKL pathway / 中华地方病学杂志

Objective:To study the effects of fluoride exposure on skeletal development of zebrafish larvae and its possible molecular mechanisms.Methods:Six hours post fertilization(6 hpf) wild-type zebrafish embryos were selected and exposed to sodium fluoride [NaF, control group (0 mg/L NaF), low fluoride group (25 mg/L NaF) and high fluoride group (100 mg/L NaF)] for 9 days. Fluorine ion selective electrode was used to detect the overall fluorine content of zebrafish larvaes, and the death and development of zebrafish larvaes were observed and counted. Bone mineralization and chondrogenesis of the zebrafish larvaes were analyzed by alizarin red staining and alcin blue staining, respectively. The expression levels of sry-related-high-mobilty-group box 9a (Sox9a), osteprotegerin (OPG) and receptor-activator of nuclear factor kappa beta ligant (RANKL) were analyzed by real-time quantitative PCR.Results:Compared with control group [(0.12 ± 0.01) μg/140 larvaes], the overall fluorine contents of zebrafish larvaes in low fluoride group [(0.28 ± 0.03) μg/140 larvaes] and high fluoride group [(0.64 ± 0.10) μg/140 larvaes] were significantly higher, and the differences were statistically significant ( P < 0.05). Compared with control group, zebrafish larvaes in high fluoride group had shorter body length, higher swim bladder loss rate and higher spinal curvature rate ( P < 0.05). The alizarin red staining area, integrated optical density (IOD) and the number of mineralized vertebrae were higher in low fluoride group, while the alcin blue staining area of cartilage formation was lower ( P < 0.05). In the high fluoride group, alizarin red staining area, IOD and the number of mineralized vertebrae were lower, while the alcin blue staining area of cartilage formation was higher ( P < 0.05). Compared with control group, the expression levels of OPG mRNA and OPG/RANKL mRNA in low fluoride group were higher ( P < 0.05); the expression level of RANKL mRNA was higher in high fluoride group, while the expression level of OPG/RANKL mRNA was lower ( P < 0.05). Conclusion:A short period of fluoride exposure from zebrafish embryo to zebrafish larvae can cause abnormal bone development of zebrafish larvae, which may be related to endochondral osteogenesis and OPG/RANKL pathway.

Fibrodisplasia Osificante Progresiva: Reporte De Casos / Progressive Ossifying Fibrodysplasia: Case Reports

Resumen Presentamos 2 casos con diagnóstico de fibrodisplasia osificante progresiva (FOP) en el Hospital de Especialidades "Eugenio Espejo". La FOP es una enfermedad rara de transmisión autosómica dominante. En la mayoría de pacientes se debe a una mutación nueva en familias no afectadas previamente. Se caracteriza por osificación heterotópica progresiva del tejido conectivo, aponeurosis, fascia, ligamentos, tendones y músculo esquelético. El diagnóstico precoz mejora el pronóstico y la calidad de vida.

Abstract. We report two cases with diagnosis of progressive ossifying fibrodysplasia (FOP) at the "Eugenio Espejo" Specialty Hospital. The FOP is a rare autosomal dominant disease. In most of the patients is due to a mutation in families not affected previously. It's characterized by progressive ossification of connective tissue, aponeurosis, fascia, ligaments, tendons and skeletal muscle. The early diagnosis improves the prognosis and the quality of life.

Effects of low-intensity pulsed ultrasound on fracture healing and caveolin-1 gene expression in the radius defects of rabbits / 复旦学报（医学版）

Objective To explore the effect of low-intensity pulsed ultrasound (LIPUS) on long bone fracture healing and to examine caveolin-1 gene expression in the radius defects of rabbits.Methods A total of 24 New Zealand rabbits with 3-mm bone defects at lower 1/3 in both radii were randomly assigned to 4 groups (n=6).Daily LIPUS treatment was performed to the right fracture sites at a intensity of 30 mW/cm2 for 20 minutes,while the left sites received sham treatment with power off.To assess the effects of LIPUS on bone defects,X-ray imaging and hematoxylin-eosin staining were applied 7,14,21,28 days after the surgery.Additionally,the immunohistochemical staining was used to determine the subcllular localization of caveolin-1 and semi-quantify the caveolin-1 level,qPCR was performed to detect the mRNA level of caveolin-1,gene Col2a1 and Col10a1,and osteocalcin.Results On day 14,the radiological score of the right radii and mineralized callus area were significantly higher than that of the left ones,both of them were elevated with time flied.Histological examination suggested that the differentiation and apoptosis of chondrocytes along with the formation and bridging of the bone trabeculas appeared earlier in the right radius defects.The immunohistochemical staining showed that on day 7 and 14,the level of caveolin-1 increased with the proliferation and differentiation of condrocytes,and was significantly higher in callus tissues on the right sites.On day 21 and 28,the mesenchymal stem cells migrated to the surface of cartilage matrix started to differentiate into osteoblasts,the level of caveolin-1 decreased,and was significantly lower on the right sites.The result of qPCR indicated that compared with the left sites the caveolin-1 gene expression on the right sites was significantly higher on day 7,while significantly lower on day 21.The mRNA expression levels of Col2a1,Col10a1 and osteocalcin on the right sites were significantly higher on day 7 and 14,but they were significantly lower on day 21 and 28,except for Col10a1 on day 28.Conclusions Advancing endochondral ossification is considered to be a crucial mechanism during long bone fracture healing promoted by LIPUS.The caveolin-1 gene expression first increased in the chondrocytes then decreased in the mesenchymal stem cells during the process.

Bone regeneration with bone marrow mesenchymal stem cells, platelet rich plasma and decellularized cartilage matrices complex / 实用口腔医学杂志

Objective:To study the bone regeneration capacity of the complex of bone marrow mesenchymal stem cells(BMSCs) and platelet rich plasma (PRP) with decellularized cartilage matrix (DCM).Methods:BMSCs were isolated from young rabbit and cultured;PRP were prepared from the fresh blood of rabbit and the DCM were come from the fresh ears of rabbits and processed into a mixture of BMSCs-PRP-DCM.The mixture was injected subcutaneously into nude mice,8 weeks after injection bone regeneration was examine by HE staining and Massons staining decellularization.Results:The BMSCs show good differentiation capacity in vitro and the cartilage fragments were well decellularized.Excellent endochondral ossification ability of the complex was observed by in vivo experiment.Conclusion:The BMSCs-PRP-DCM complex has good capacity of endochondral ossification.

Progress in exogenous factors affecting the growth and remodeling of condylar process / 华西口腔医学杂志

Condyle is a critical growth region of the mandible where mandible by endochondral ossification occurs. Condylar cartilage belongs to the secondary cartilage, which is not only affected by genetic factors but also by stress, drug intake, and other local factors. To promote the growth of the mandible, various exogenous and local factors were used to alter the biological environment of the condylar cartilage to stimulate endochondral ossification. This article reviews studies on the influence of exogenous factors on condylar growth and reconstruction. This literature review will provide a reference point for the treatment of patients with mandibular retraction.

Effect and mechanism of total flavone of epimedium on primary callus formation in ovariectomized rats with fractures / 中国骨伤

<p><b>OBJECTIVE</b>To explore the effects and related mechanisms of total flavone of epimedium treatment(TFE)on primary callus for mation in ovariectomized rats.</p><p><b>METHODS</b>Forty male SD rats weighted from 209 to 246 g and aged 6 to 8 weeks were selected. Six weeks after ovariectomy a femur fracture model with middiaphyseal segment fracture was established, estimated and randomly divided into TFE group (150 mg·kg⁻¹·d⁻¹) and control group(received saline). HE staining was used to evaluate the morphologic difference of primary callus during the bone callus healing between these two groups. The relative expression of Runt-related transcription factor 2(Runx2) mRNA in the callus was identified by real-time polymerase chain reaction. Immunohistochemical technique was used to observe the Casein kinase 2-interacting protein 1(CKIP-1) protein level in the callus of the two groups. Maximum fracture load was tested by three point bend test.</p><p><b>RESULTS</b>The BMD, primary callus volume, trabecular member(Tb.N) and trabecular thickness(Tb.Th) were higher in TFE group than that in control group(<0.001). The Tb.N and Tb.Th of primary callus were higher in TFE group than control group (=0.001). The volume and bone volume/tissue volume of primary callus were in TFE group than control group(<0.01). The trabecular separation(Tb.Sp) of primary callus were in control group higher than TFE group(<0.01). The HE staining of the 6 week slices showed that the degree of cartilage ossification in callus of the TFE group was significantly higher than that in control group under high magnification. Real-time PCR revealed that the comparative expression of Runx2 mRNA in control group was higher than that in TFE group(<0.001); the positive number of CKIP-1 was less in TFE group than that in control group (<0.001). TFE could increase the maximum load of the primary callus (<0.001).</p><p><b>CONCLUSIONS</b>TFE can promote the cartiage ossification of callus in ovariectomized rats, enhancing the bone strength and bone quality in the process of fracture healing via the CKIP-1/Runx2 pathway.</p>

Use of mandibular chin bone for alveolar bone grafting in cleft patients / 대한악안면성형재건외과학회지

BACKGROUND: We evaluated and compared the outcomes of different ossification processes in patients with alveolar cleft in whom correction was performed using endochondral bone graft or intramembranous bone graft. METHODS: The patients were divided into two groups: the endochondral bone (iliac bone or rib bone) graft group and the intramembranous bone (mandibular bone) graft group. Medical records and radiologic images of patients who underwent alveolar bone grafting due to alveolar cleft were analyzed retrospectively. Through postoperative and follow-up radiologic images, the height of the interdental bone septum was classified into four types based on the highest point of alveolar ridge. Then, the height of the interdental bone septum and the area of the bone graft were evaluated according to the type of bone graft. In addition, the occurrence of complications and the need for an additional bone graft, the result of postoperative orthodontic treatment, and the eruption of impacted teeth were investigated. RESULTS: Thirty patients were included in this study. There was no significant difference in the change of the interdental bone height and the area of the bone graft according to the type of bone. There was no significant difference in the success rate of the surgery according to the type of bone. One patient underwent an additional bone graft surgery during the follow-up period. CONCLUSIONS: The outcomes of alveolar bone grafting were not significantly different according to the type of bone graft. If appropriate to the size of the recipient site, the chin bone is a useful graft material in alveolar cleft, as is the iliac bone.

5-Aza-2'-deoxycytidine acts as a modulator of chondrocyte hypertrophy and maturation in chick caudal region chondrocytes in culture / 대한해부학회지

This study was carried out to explore the effect of DNA hypomethylation on chondrocytes phenotype, in particular the effect on chondrocyte hypertrophy, maturation, and apoptosis. Chondrocytes derived from caudal region of day 17 embryonic chick sterna were pretreated with hypomethylating drug 5-aza-2'-deoxycytidine for 48 hours and then maintained in the normal culture medium for up to 14 days. Histological studies showed distinct morphological changes occurred in the pretreated cultures when compared to the control cultures. The pretreated chondrocytes after 7 days in culture became bigger in size and acquired more flattened fibroblastic phenotype as well as a loss of cartilage specific extracellular matrix. Scanning electron microscopy at day 7 showed chondrocytes to have increased in cell volume and at day 14 in culture the extracellular matrix of the pretreated cultures showed regular fibrillar structure heavily embedded with matrix vesicles, which is the characteristic feature of chondrocyte hypertrophy. Transmission electron microscopic studies indicated the terminal fate of the hypertrophic cells in culture. The pretreated chondrocytes grown for 14 days in culture showed two types of cells: dark cells which had condense chromatin in dark patches and dark cytoplasm. The other light chondrocytes appeared to be heavily loaded with endoplasmic reticulum indicative of very active protein and secretory activity; their cytoplasm had large vacuoles and disintegrating cytoplasm. The biosynthetic profile showed that the pretreated cultures were actively synthesizing and secreting type X collagen and alkaline phosphatase as a major biosynthetic product.

The study of the mechanism in the endochondral ossification of bone mesenchymal stem cells in mice by continued enhanced function of fibroblast growth factor type Ⅱ receptor mutation / 重庆医学

Objective To study the role of ERK signal pathway in the endochondral ossification of bone mesenchymal stem cells ,and to explore the mechanism of ERK signal pathway in persistent enhanced FGFR2 function on development of mice BMSCs by a knock‐in mouse model with the FGFR2S252W/+ .Methods Mice with neo‐FGFR2 gain‐of‐function mutation were mated with EII‐Cre mice .The genotype of generation mice were identified by PCR and divided into wild type group and mutant type group ac‐cording to their genotype .6 week‐old mice were sacrificed to receive bone mesenchymal stem cells .The western blot was used to compare the level of P‐ERK and ERK and the RT‐PCR was applied to detect the genes of Col2 ,Col10 ,OC ,OP in chondrogenic dif‐ferentiation medium of BMSCs .Then ,treatment of cultured BMSCs with PD98059 ,compare the changes of genes and utilize the in vitro culture of long bones detect the role of ERK signal pathway in the endochondral ossification by FGFR2 mutant .Results We successfully derive BMSCs from FGFR2S252W/+ mutant mice and found the activity of ERK signal pathway of FGFR2S252W/+ was en‐hanced .After been cultured in chondrogenic differentiation medium ,the expressions of the BMSCs mRNA of Col2 ,Col10 from mu‐tant group were decreased ,while the expressions of OC ,OP were increased .Those OC ,OP genes levels showed an increased treated by PD98059 .Using in vitro culture of long bones ,we found the retardation of total length growth of long bones has been rescued by PD98059 treatment ,suggesting that ERK signal pathways was responsible for the retarded long bone development in FGFRS252W/+mice .Conclusion The results indicate these effects are mediated by the ERK signal pathway .Furthermore ,the retardation of long bones has been recued by PD98059 treatment ,suggesting that ERK signal pathway is responsible for the retarded long bone devel‐opment in FGFR2S252W/+ mice .

Effects of Bisphosphonate on the Expression of Matrix Enzymes during Endochondral Ossification / 체질인류학회지

Bisphosphonates have been reported to have chondroprotective activities in addition to its original functions. However, mechanisms for these just began to be elucidated. Under the hypothesis that bisphosphonates may regulate expression and activities of matrix enzymes during degradation of cartilage for bone formation, we administrated an alendronate (1 mg/kg) to newborn rats subcutaneously once a day for 4, 7, and 10 days. To identify the effects of alendronate on cartilage, thickness of cartilage layer was measured by histomorphometry on the proximal epiphysis of tibia. Immunofluorescence staining and RT-PCR were performed to investigate the expressions of matrix enzymes in both in vitro and in vivo. MTS assay revealed that at 10(-3) M in concentration, alendronate significantly reduced viability of chondrocytes. The mRNA expressions of MMP-1, MMP-9, EMMPRIN, and TIMP-3 in primary chondrocytes were decreased by the alendronate treatment. Interestingly, TIMP-1 mRNA expression was significantly increased, whereas a constitutive form, TIMP-2 was relatively unchanged by the treatment. The thickness of proliferating layer at postnatal day 7 was not significantly different, whereas thickness of hypertrophied layer was significantly thicker in the alendronate group than in the control (p<0.01). Immunofluorescence demonstrated that the expressions of MMP-9, TIMP-2 and -3 were reduced, whereas TIMP-1 expression was increased by the alendronate administration. These results suggest that the alendronate have chondroprotective properties by down-regulation of MMPs and up-regulation of TIMPs during endochondral ossification.

The expression of pimonidazole hydrochloride(HP-1)in rat condylar cartilage in the early growth stage / 实用口腔医学杂志

Objective:To investigate hypoxia location in condylar cartilage in the early growth stage of rats.Methods:40 Sprague-Dawley rats were breastfed from 1 4 d to 21 d of age.1 0 rats were sacrificed at 1 2,24,48 and 96 h respectively after initiation of normal food at 21 d of age.The rats were administered pimonidazole hydrochloride (HP-1 )at a dose of 60 mg/kg by intraperitoneal injection 2 h before sacrifice.The expression of HP-1 in the whole condylar cartilage was detected by immunohistochemical staining.Results:HP-1 was mainly expressed in the chondrocytes of the fibrous and proliferative layer of cartilage,primarily concentrated in the weight-bearing area of joint-anterior aspect of the condyle and posterior aspect of the articular eminence at all time points.The highest expres-sion was observed at 24 h after initiation of normal food (P <0.01 ).Conclusion:In the early growth stage of rats,dietary loading may directly induce hypoxia in uper layer of condylar cartilage,the hyoxia level may change with time of dietary loading.

Una propuesta teórica y conceptual para el modelado de la aparición de centros de osificación en diferentes tipos de huesos planos y largos / Une proposition théorique et conceptuelle pour le modelage des centres d'ossification dans différents types d'os plats et longs / Theoretical and conceptual proposal for appearance modeling of ossification centers in different types of flat and long bones

Se mostró un contexto de trabajo sobre el modelado de procesos de formación endocondral en cualquier tipo de osificación presente en los huesos del cuerpo. Siguiendo la suposición de que PTHrP (hormona paratiroidea) e Ihh (proteína Indian hedgehog) forman un bucle regulatorio bioquímico para el proceso endocondral, y BMP2 (proteína morfogenética de hueso-2) y Noggin en el intramembranoso, se implementaron los mecanismos regulatorios de este proceso. Para ello se utilizó un conjunto de ecuaciones de reacción-difusión ampliamente usadas en morfogénesis, en las que los factores bioquímicos se suponen secretados por células precursoras, mesenquimales y condrocitos, en el caso intramembranoso y endocondral, respectivamente. Se concluyó que la solución condujo a patrones denominados de Turing, que representan estos procesos de osificación de una forma muy aproximada(AU)

A work context on the modeling of endocondral formation process in any type of ossification present in the bones of the human body was shown. Assuming that PTHrP and Ihh form a biochemical regulatory loop for the endocondral process and BMP2 and Noggin for the intramembranous one, regulatory mechanisms for this formation process were implemented. For this purpose, a set of widely used diffusion reaction equations in morphogenesis were used in which the biochemical factors are supposed to be secreted by precursor cells, mesenchymal and chondrocytes in the case of intramembranous and chondroidal respectively. It was concluded that the solution led to the denominated Turing patterns which represent these ossification processes in a highly estimated form(AU)

Dans ce travail, un modelage du processus de formation endochondrale dans tout type d'ossification des os du corps est présenté. Supposant que PTHrP (peptide lié à l'hormone parathyroïdienne) et Ihh (protéine Indian Hedgehog) forment une boucle biochimique régulatrice pour le processus endochondral, et BMP2 (protéine morphogénétique osseuse-2) et Noggin pour le processus endomembraneux, des mécanismes régulateurs se produisent alors dans ce processus. C'est pourquoi, un groupe d'équations de réaction-diffusion largement utilisées dans la morphogenèse, où les facteurs biochimiques sont apparemment sécrétés par des cellules souches, mésenchymateuses et chondrocytes, a été utilisé. On a conclu que la solution a conduit à des modèles dits de Turing, représentant ces processus d'ossification de manière très similaire(AU)

Representación del desarrollo de la espongiosa primaria por medio de un sistema de reacción-difusión: Una hipótesis sobre el inicio de la formación de hueso inmaduro. Parte 1: Descripción del modelo / Representation of the development of the primary spongiosa by means of a reaction-diffusion system: a hypothesis on the onset of immature bone formation. Part 1: Model description

Se presenta un modelo bioquímico que predice la formación de la arquitectura de la espongiosa primaria, a partir de la interacción de 2 factores moleculares: VEGF (factor de crecimiento endotelial vascular) y MMP13 (metaloproteinasas 13). Se supone que el MMP13 regula la degradación del cartílago y el VEGF permite la vascularización y el avance del frente de osificación mediante la presencia de osteoblastos. El acople de este conjunto de moléculas se representa mediante ecuaciones de reacción-difusión con parámetros en el espacio de Turing, y se obtiene como resultado un patrón espacio-temporal estable que da paso a la formación de las trabéculas presentes en el tejido esponjoso...

A biochemical model is presented which predicts the formation of the architecture of the primary spongiosa, based on the interaction of two molecular factors: VEGF (vascular endothelial growth factor) and MMP-13 (metalloproteinases-13). It is assumed that MMP-13 regulates cartilage degradation, and VEGF allows vascularization and the advance of the ossification front through the presence of osteoblasts. The coupling of this set of molecules is represented by means of reaction-diffusion equations with Turing space parameters, and a stable spatio-temporal pattern is obtained which leads to the formation of the trabeculae present in the spongy tissue...

Representación del desarrollo de la espongiosa primaria por medio de un sistema de reacción-difusión: Una hipótesis sobre el inicio de la formación de hueso inmaduro. Parte 2: Implementación numérica / Representation of the development of the primary spongiosa by means of a reaction-diffusion system: a hypothesis on the onset of immature bone formation. Part 2: Numerical implementation

Se presenta la implementación numérica del modelo bioquímico descrito mediante el sistema de reacción-difusión de la parte 1. De los resultados obtenidos se puede concluir que la retroalimentación química de los 2 factores moleculares a través de un sistema de reacción-difusión (RD) con parámetros en el espacio de Turing, puede explicar la aparición de los patrones espacio-temporales encontrados en la arquitectura de la espongiosa primaria. Para la solución numérica fue usado el método de los elementos finitos junto con el método de Newton-Raphson para aproximar las ecuaciones diferenciales parciales lineales. Los patrones de osificación obtenidos pueden representar la formación de la espongiosa primaria durante la osificación endocondral...

A presentation is made of the numerical implementation of the biochemical model described by means of the reaction-diffusion system in Part 1. Based on the results obtained it may be concluded that the chemical feedback of the two molecular factors by means of a reaction-diffusion (RD) system with Turing space parameters may explain the appearance of the spatio-temporal patterns found in the architecture of the primary spongiosa. For the numerical solution, use was made of the finite element method in combination with the Newton-Raphson method to approximate the linear partial differential equations. The ossification patterns obtained may represent the formation of the primary spongiosa during endochondral ossification...

Un modelo matemático de la placa de crecimiento / A mathematical model of growth plate

La placa de crecimiento es una estructura que está conformada por células, denominadas condrocitos, que se ordenan en columnas y confieren el alargamiento del hueso debido a su proliferación e hipertrofia. En cada columna se pueden observar condrocitos en estado proliferativo (que se dividen constantemente), e hipertrófico (que crecen para obtener una forma casi esférica). Estas células expresan diferentes proteínas y moléculas a lo largo de su vida media y tienen un comportamiento especial que puede depender de su entorno local mecánico y bioquímico. En este artículo se desarrolla un modelo matemático que describe la relación entre la geometría, el crecimiento por proliferación e hipertrofia y la invasión vascular con los factores bioquímicos y mecánicos presentes durante el desarrollo endocondral

The growth plate is a structure composed of cells called chondrocytes arranged in columns and causing the bone lengthening due to its proliferation and hypertrophy. In each column it may observed the presence of chondrocytes in proliferation stage (constantly divided) and hypertrophy stage (growing to obtain a almost spherical shape). These cells express different proteins and molecules during half-life and have a special behavior that may to depend on its mechanical or biochemical local environment. In present paper it is developed a mathematical model describing the relationship among the geometry, proliferation and hypertrophy growth and the vascular invasion by biochemical and mechanical factors present during the endochondral development

Modelamiento matemático de la enfermedad de Legg-Calvé-Perthes / Mathematical modeling of Legg-Calvé-Perthes disease

La enfermedad de Legg-Calvé-Perthes es un desorden caracterizado por la necrosis avascular de la cabeza femoral del esqueleto en desarrollo. Aunque la enfermedad fue descrita hace un siglo, aún existe gran controversia respecto a su etiología y al tratamiento que se le debe dar. Tanto la etiología como el tratamiento tienen una fuerte relación con eventos biológicos y mecánicos. Un entendimiento de dichos eventos y de su acción combinada, podría dar lugar a una mejor comprensión y manejo de la enfermedad. Este trabajo propone un acercamiento a esta comprensión mediante el uso del modelamiento computacional, el cual debe tener en cuenta, entre otros factores, la patogénesis de la enfermedad y los diferentes resultados en dependencia de la edad a la cual esta se manifieste en el niño

The Legg-CalvÚ-Perthes disease is a disorder characterized by the avascular necrosis of femoral head of developing skeleton. Although this disease was described a century ago still there is a significant controversy on its etiology and its treatment. Between etiology and treatment there is a close relation with biological and mechanical events. The knowledge of such events and of its combined action, could give rise to a better understanding and management of this disease. Present paper proposes a approach to this understanding by means of the use of a computer modeling, which must to has into account among other factors, the disease pathogenesis and the different results depending on age of appearance in the child

The Role of Microtubule in the Regulation of Endochondral Bone Formation in the Developing Mouse Cranial Base / 체질인류학회지

Endochondral bone formation of the developing cranial base is a complex process. This mechanism requires precise orchestration of many cellular events and cartilage matrix metabolism, such as proliferation, becoming round in shape, termination of proliferation, hypertrophic size-increase, and finally programmed cell death. Active formation and degradation of cartilage matrix take place, in which microtubules are involved for intracellular events; bone apposition follows these events. However, the involvement of microtubules during these changes in the developing cranial base has not been identified yet. Thus, we investigated the involvement of microtubules in the regulation of endochondral bone formation during cranial base development. Using tubulin-binding drug nocodazole, we examined the effects of altering the structure and function of microtubules during in vivo organ culture of the mouse cranial base. Cultured specimens were analyzed with HE staining, immunohistochemistry, and cell counting in order to study the morphological and molecular changes that occurred in the tissues. Disruption of the microtubular array by nocodazole reduced cells expressing proliferation marker Ki67, osteogenic marker BSP, and BMP4 within the sphenooccipital synchondrosis region; chondrocyte hypertrophy was ceased in the hypertrophic zone; degeneration of cartilage matrix and bone matrix apposition was inhibited in the ossification center of the basooccipital cranial base. Our data demonstrated that disruption of microtubules by nocodazole have multiple inhibitory effects on the sequential changes that occur during endochondral bone formation, suggesting the importance of normal microtubule-polymerization in cranial base development.

Role of hypoxia inducible factor-1α and VHL in murine endochondral ossification / 上海交通大学学报（医学版）

Objective To investigate the role of hypoxia inducible factor-1α (HIF-1α) and von Hippel-Lindau (VHL) in murine endochondral ossification. Methods The knockout of HIF-1α or VHL gene in murine osteoblasts was accomplished by conditional knockout technique at 4th, 8th and 12th week, and the differences between wild-type group and knock-out group in endochondral ossification were detected by HE staining, micro-CT scanning, trabecular bone area measurement, calcium content measurement, tetracycline fluorescence labeling, Real-time PCR and Western blotting. Results After knockout of HIF-1α gene in osteoblasts, the expression of vascular endothelial growth factor ( VEGF) reduced, the rate of new bone formation stepped down, the content of calcium became less, and the trabecular bone volume decreased (P <0.05) . After knockout of VHL gene in osteoblasts, the expression of VEGF increased, the rate of new bone formation stepped up, the content of calcium became more, and the trabecular bone volume was promoted (P < 0.001). Conclusion During murine endochondral ossification, VHL/HIF-1α signal pathway promotes angiogenesis through the stimulation of VEGF expression, which subsequently accelerates osteogenesis.

Effects of epidermal growth factor receptor on endochondral ossification and recruitment of osteoclasts in mice / 吉林大学学报(医学版)

Objective To determine the role of epidermal growth factor receptor(EGFR) signaling in endochondral ossification.Methods Long bones,from EGFR knockout mice(EGFR-/-),wild type(EGFR+/+) and(or) heterozygous mice(EGFR+/-) were collected and Trichrome Masson staining,in situ hybridization and tartrate-resistant acid phosphatase(TRAP) staining were used to observe endochondral ossification and recruitment of osteoclasts;Osteoclast formation was observed by addition of EGFR tyrosine kinase inhibitor AG1478 to the cultured osteoclasts from bone marrow cells.Results Due to the same phenotype of EGFR+/+ and EGFR+/-,they were regarded as EGFR+/+ in our study.EGFR deficiency caused delayed primary endochondral ossification of cartilage anlage and delayed osteoclast recruitment.The hypertrophic cartilage area in EGFR-/-mice was about 5 times longer than that in EGFR+/+ mice.There was different distribution of MMP-9 between EGFR+/+ and EGFR-/-in E16.5,but there was no difference about the quantity of MMP-9 in osteoclasts between EGFR-/-and EGFR+/+.However,inhibition of EGFR signaling with AG1478 significantly decreased osteoclast formation compared with control group with DMSO(P

The study on the bone resorption rate after vertical alveolar ridge augmentation

< 0.05). Also significant difference is on volume resorption on two groups (P < 0.05). CONCLUSION: We found that more bone resorption occurred with iliac(endochondral) bone and when we use intraoral bone, that bone can maintain their vitality for alveolar ridge augmentation.