Effect of different oxygen tension on the cytoskeleton remodeling of goat temporomandibular joint disc cells / 华西口腔医学杂志

Objective The effect of different oxygen tensions on the cytoskeleton remodeling of goat temporomandibular joint (TMJ) disc cells were investigated. Methods Goat TMJ disc cells were cultured under normoxia (21% O₂) and hypoxia (2%, 4%, and 8% O₂). Toluidine blue, picrosirius red, and type Ⅰ collagen immunocytochemical staining were performed to observe the changes in cell phenotype under different oxygen levels. Immunofluorescent staining and real-time reverse transcription-polymerase chain reaction analysis were then performed to identify actin, tubulin, and vimentin in the cultured disc cells. Results TMJ disc cells still displayed fibroblast characteristics under different oxygen levels and their cytoskeletons had regular arrangement. The fluorescence intensities of actin and vimentin were lowest at 4% O₂(P<0.05), whereas that of tubulin was highest at 2% O₂ (P<0.05). No significant difference among the other groups was observed (P>0.05). Actin mRNA levels were considerably decreased at 2% O₂ and 4% O₂ in hypoxic conditions, while actin mRNA expression was highest in 21% O₂. Tubulin mRNA levels considerably increased at 2% O₂, while tubulin mRNA expression was lowest in 8% O₂ (P<0.05). Vimentin mRNA expression was lowest at 4% O₂ and highest at 21% O₂, and significant differences were observed between vimentin mRNA expression levels among these oxygen levels (P<0.05). Conclusion Cytoskeletons were reconstructed in different oxygen tensions, and 2% O₂ may be the optimal oxygen level required to proliferate TMJ disc cells.

Collagen structure and biomechanical properties of the goat temporomandibular joint disc / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To establish objectively biomechanical criteria for temporomandibular joint disc tissue engineerings.</p><p><b>METHODS</b>Eight temporomandibular joint discs from a four-month-old goat were separated completely. A cylindrical sample with diameter of 3 mm in the anterior, intermediate, and posterior bands was obtained, and the samples underwent pre-compression test with three cycles under a speed of 0.025 mm · s⁻¹. With the end condition for the maximum load of less than 4.9 N and 1.5 mm compression displacement, the formal compression test was performed with the same speed. Moreover, this test obtained the stress-strain relationship and elastic modulus of each disc band. Ultrastructure and collagen fiber orientation of the district zone were observed by scanning electron microscope and polarized light microscope.</p><p><b>RESULTS</b>1) The physiological strain range of an articular disc was within 10%, and the quasilinear constitutive equation of articular disc tissues can be fitted with the polynomial function: y = ax + bx² + cx³. 2) The elastic modulus of the intermediate disc zone was the largest (P < 0.05). No significant difference existed between the anterior and posterior bands (P = 0.361). 3) Scanning electron microscope and polarized light microscope showed an annular disc collagen network structure, which was the internal part of the goat temporomandibular joint disc. The collagen arrangement of intermediate bands was tensely arranged anterior-posteriorly. The collagen of anterior and posterior bands went through mediolaterally with intersection of anterior-posterior branch fibersd.</p><p><b>CONCLUSION</b>Annular collagen network structure is the basis for goat temporomandibular joint disc compression resistance properties. The intermediate band demonstrated higher compression resistance performance than the anterior and posterior bands.</p>

Topography and mechanical property of goat temporomandibular joint disc cells / 华西口腔医学杂志

<p><b>OBJECTIVE</b>This study is performed to investigate the cell topographies and biomechanical properties of two different types of temporomandibular joint (TMJ) discs from goats by using JPK Nano Wizard 3 biological atomic force microscopy (AFM). This process provides a guideline for selecting seed cells for TMJ disc tissue engineering.</p><p><b>METHODS</b>TMJ disc cells from primary goats were cultured by monolayer culture method. AFM was used to contact scan the topographies of the two types of TMJ disc cells under physiological environment. Approximately 20 chondrocyte-like and fibroblast-like cells were selected randomly to plot the force-versus-distance curves of the cytoplasm and nucleus. Young's modulus and adhesion were analyzed by JPK Data Processing.</p><p><b>RESULTS</b>The triangle-shapednucleus of the chondrocyte-like cell occupied a large portion of the cell. Cytoskeleton was arranged dendritically on the surface. Pseudopodia were extended from cell edges. The spindle-shaped nucleus of the fibroblast-like cell occupied a significantly larger region compared with the cytoplasmic region. Cytoskeleton was arranged regularly. Cell edges were smooth with less pseudopodia extended. No difference was found in the surface roughness between the two types of cells. According to the force-versus-distance curves, the Young's moduli of the two types of cells were not statistically different (P>0.05), but differences were found in the cytoplasmic regions (P=0.047). No statistical difference was found in the adhesions between the two types of cells (P>0.05).</p><p><b>CONCLUSION</b>The AFM topography and curves were compared and analyzed. The two types of TMJ disc cells exhibited significantly different topographies, but only slight difference in their mechanical abilities.</p>

Morphological changes of goat bone marrow mesenchymal stem cells differentiating into fibrochondrocytes / 中国组织工程研究

BACKGROUND:Our preliminary studies have shown that basic fibroblast growth factor can induce the differentiation of bone marrow mesenchymal stem cells into disc cells of the temporomandibular joint, and for basic fibroblast growth factor, 10μg/L is superior to 5μg/L in col agen synthesis. OBJECTIVE:To observe ultrastructural changes of bone marrow mesenchymal stem cells after being induced by different concentrations of basic fibroblast growth factor. METHODS:We cultured primary sheep bone marrow mesenchymal stem cells and selected passage 3 and 4 cells at good growth state. Bone marrow mesenchymal stem cells were stimulated with 5 and 10μg/L basic fibroblast growth factor and their growth state was observed under inverted phase contrast microscope. Uninduced cells served as controls. The slides with cellcrawling pieces were stained with Safranin O, picrosirius and type I col agen immunohistochemistry at days 7, 14 and 21, respectively. Simultaneously we col ected the cells at day 21 to observe the ultrastructural changes of bone marrow mesenchymal stem cells. RESULTS AND CONCLUSION:After being induced with different concentrations of basic fibroblast growth factor, bone marrow mesenchymal stem cells were able to differentiate into disc cells of the temporomandibular joint;and after being induced with 10μg/L basic fibroblast growth factor, cells were more like fibroblast-like cells of the temporomandibular joint disc. These findings indicate that bone marrow mesenchymal stem cells have morphological basis for differentiation to the fibroblast-like cells of the temporomandibular joint disc.

Effects of basic fibroblast growth factor on bone marrow mesenchymal stem cell differentiation into temporomandibular joint disc cells / 生物医学工程学杂志

The present paper is aimed to observe the effects of basic fibroblast growth factor (bFGF) on bone marrow mesenchymal stem cell (BMSCs) differentiation. The bFGF was used to stimulate BMSCs and histology, immunohistochemistry and enzyme linked immunosorbent assay (ELISA) were used to examine the extracellular matrix produced by induced BMSCs, evaluated the feasibility of BMSCs being the seeding cells of temporomandibular joint (TMJ) disc tissue engineering. The results showed that having been induced with bFGF, the BMSCs could differentiate into fibroblast-like cells, which could synthesize GAG and collagen type I matrix. So it is feasible for BMSCs as seeding cells for engineered TMJ disc.

Research progress of anticarious Chinese herbal / 中国中药杂志

Caries is a chronicly infectious disease which happens to the hard tissue of the teeth and is the most common dental disease of human. Many scholars have devoted to research anticarigenics drugs and the Chinese herbal was considerably concerned. The paper briefly introduces kinds of anticarigenics Chinese herbals, such as Turkish galls, TFA and Magnolia.

Isolation and cultivation of goat temporomandibular joint disc cells / 实用口腔医学杂志

Objective:To study the isolation, culture and identification of the TMJ cells and to observe the biological characteristics of cultured fibrochondrocytes. Methods:The TMJ discs were dissected from two 1 month goats under sterile conditions and were digested with collagenase. The cells were collected. Morphological changes and attachment efficiency were constantly observed under phase-contrast microscope. Immunohistochemical staining for type I collagen as well as toluidine blue staining were performed. Ultrastructures of the TMJ cells were observed under transmission electron microscope. Results: Most of the primary fibrochondrocytes presented a short spindle-shape while the rest showed polygon-shape. On the 7th day, the perliferating fibrochondrocytes started to contact each other to form a monolayer covering the bottom of the incubation disc. Immunohistochemical staining of type I and toluidine blue staining exhibited positive results. The fibrochondrocytes cytoplasms were rich in mictochondria and endoplasm reticulum. Conclusion: The fibrochondrcytes isolated from one-month-old goat TMJ disc have good proliferation ability in vitro and cells from passage 1 to 3 might be used as seed cells for TMJ disc tissue engineering.

Type and distribution of cells in goat temporomandibular joint discs and its significance in tissue engineering design / 中国组织工程研究

BACKGROUND:There is no common cognition in the cell type in the temporomandibular joint(TMJ)discs,and names describing TMJ disc cells also vary a lot.OBJECTIVE:To characterize the type and the distribution of cells in the TMJ disc of goats DESIGN,TIME AND SETTING:A single sample observation was completed in Cettutar and Motecutar Biologicat Center and Electron Microscope Center of Lanzhou University from March to May in 2007.MATERlALS:TMJ discs were obtained from two one-month-old healthy goats that were slaughtered freshly.METHODS:Bilateral TMJ discs of goats were cut off completely and were divided into 6 parts by 3 cuts in the major axis direction (mediolaterally)and 2 cuts in the minor axis direction(anteroposteriorly).Then the marked samples were fixed in 10%neutral formalin Iiquid for 24 hours and embedded by paraffin.MAIN OUTCOME MEASURES:Hematoxylin and eosin staining were used to identify regional variation of cell type and cellnumbers.Toluidine blue staining and collagen type Ⅰimmunohistochemical assay were performed to test the distribution of collagens.Transmission etectren microscopy was used to observe the ultrastructure of cells of goat TMJ discs.RESULTS:TMJ discs were comprised of cells and collagen fibers distributing unevenly.Collagens were mostly type Ⅰ.Collagen fibers were wave or crimping and approximately parallel to each other.with cells scattered in their matrix.Fibroblast-like cells and chondrocyte-like cells were the main two types of cells existing,with the former predominating over the later in a ratio of 2.05:1 approximately.There were no significant regional differences in cell type and distribution statistically.Transmission electron microscopy denoted that fibroblast-iike cells have fairly larger fusiform or irregular nuclei with very few organelles,while the chondrocyte-like cells exhibited round or elliptical nuclei,well defined pericellular electron lucent zones,unconspicuous cytocysta and non-distinctive pseudopodia CONCLUSION:There are no significant differences in type,number and arrangement of cells in TMJ discs of one-month-old goats statistically,with Fibroblast-like cells predominating slightly over chondrocyte-like cells.

The exploration of phantom system in endodontic teaching / 中华医学教育探索杂志

This article described the application of the phantom system in the experiment teaching of Endodontics.Through the process of teaching,we realized that the way of simulation in the experiment teaching not only can enhance the enthusiasm of students,but also can consolidate the basis of theoretical knowledge and improve the clinical skills of students.The system has become the necessary equipment and means in experimental teaching of modern stomatology.It is worth further promotion and application in dental teaching.

Condylar path of the patients with severe dental attrition / 实用口腔医学杂志

Objective:To study the characteristics of condylar path in the patients with severe dental attrition.Methods:Using D5A De nar fully adjustable articulator and the Pantronic recording system, the kinemat ic character of condylar paths of 15 patients with severe occlusal attrition was investigated. In addition, the effects of posterior condylar determinants on oc clusal rehabilitation were studied in 5 cases. Results: The mean intercondylar distance of the patients was (60.72?4.40) mm, and the immediate side shift (ISS) was 1.35 mm(right)and 1.24 mm(left),the progressive si de shift (PSS) were 14.65 degrees (right) and 17.11 degrees (left),respectively. The Pantronic protrusive condylar guidance (PRO) were 23.45 degrees (right) and 26.85 degrees (left); The Pantronic nonworking path (ORB) was 26.50 degrees and the Fisher angle was present between protrusive path and nonworking path. In th e 5 cases of occlusal rehabilitation ISS, PSS and Panotronic reproducibility ind ex (PRI) were decreased.Conclusion: Occlusal rehabilitation main ly affect ISS, PSS and PRI.