Browsing by Subject "Mandible"

Now showing 1 - 5 of 5
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    Development of the mouse mandibles and clavicles in the absence of skeletal myogenesis
    (Murcia : F. Hernández, 2007) Rot-Nikcevic, I.; Downing, K.J.; Hall, B.K.; Kablar, B.
    In this report we employed double-knock-out mouse embryos and fetuses (designated as Myf5-/-: MyoD-/- that completely lacked striated musculature to study bone development in the absence of mechanical stimuli from the musculature and to distinguish between the effects that static loading and weight-bearing exhibit on embryonic development of skeletal system. We concentrated on development of the mandibles (= dentary) and clavicles because their formation is characterized by intramembranous and endochondral ossification via formation of secondary cartilage that is dependent on mechanical stimuli from the adjacent musculature. We employed morphometry and morphology at different embryonic stages and compared bone development in double-mutant and control embryos and fetuses. Our findings can be summarized as follows: a) the examined mutant bones had significantly altered shape and size that we described morphometrically, b) the effects of muscle absence varied depending on the bone (clavicles being more dependent than mandibles) and even within the same bone (e.g., the mandible), and c) we further supported the notion that, from the evolutionary point of view, mammalian clavicles arise under different influences from those that initiate the furcula (wishbone) in birds. Together, our data show that the development of secondary cartilage, and in turn the development of the final shape and size of the bones, is strongly influenced by mechanical cues from the skeletal musculature.
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    Mandibular bone alterations of ovariectomized rats under vitamin D insufficiency
    (Murcia : F. Hernández, 2008) Said, Faika; Ghoul-Mazgar, Sonia; Ruhin, Blandine; Abdellaoui, Mohieddine; Chlaghmia, Faycel; Safta, Sihem; Guezguez, Leila; Saidane-Mosbahi, Dalila; Khemiss, Fathia
    Experimental osteoporosis was studied in mandible bone by means of ovariectomy and vitamin D insufficiency. METHODS: 42 female Wistar rats were divided into the following four groups: (1) ovariectomized rats maintained in 12h day-night light conditions (ov-l), (2) ovariectomized rats maintained in 24h dark light conditions (ov-ob), (3) sham-operated rats maintained in 12h day-night light conditions (ch-l) and (4) sham-operated rats maintained in 24 h dark conditions (ch-ob). 12 weeks later the animals were sacrificed, the mandibles were excised, cleaned and weighed, the right side of the mandibles were histologically examined and the left side of the mandibles were prepared for mineral phase analysis by X-ray diffraction. Immunohistochemical analysis was performed to detect apoptotic cells by anti-PARP p85 antibody. RESULTS: In group 2, the weight of mandibles significantly decreased. Chondroid areas were observed in ovariectomized groups and polarized light observation validated the collagen distribution disturbance in these groups (groups 1 and 2). Apoptotic osteoblasts were localized in groups 1, 2 and 4. They were numerous in group 2. The mineral phase analysis did not find differences between the groups. CONCLUSION: This study validates a new model of osteoporotic animal associating estrogens deficiency and vitamin D insufficiency where matrix synthesis and osteoblast biology are altered, but not biomineralization.
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    Puerarin and zinc additively prevent mandibular bone loss through inhibiting osteoclastogenesis in ovariectomized rats
    (Universidad de Murcia. Departamento de Biología Celular e Histología, 2017) Liu, Hao; Li, Wei; Jia, Shengnan; Li, Binbin
    Puerarin and zinc play a key role in preventing osteoporotic-related bone loss. Previous research on puerarin or zinc mainly focused on the antiosteoporotic effects of long bone. However, it is obscure for puerarin or zinc to prevent mandibular osteoporosis. Here, we explore the effects on additive coadministration of puerarin and zinc on preventing mandibular bone loss in ovariectomized rats, and evaluate the underlying mechanisms ex vivo. Rats were ovariectomized and administrated puerarin, zinc or both. After 12 weeks, bone mineral density (BMD) and histomorphometry of mandibles were measured by micro-CT. The mechanical properties were determined using a threepoint bending test. Then, osteogenic differentiation of primary bone marrow stromal cells (BMSCs) and osteoclastogenesis of bone marrow mononuclear were performed ex vivo. The culture supernatant and serum level of bone biochemical markers including osteoprotegerin (OPG), osteopontin (OPN), receptor activator of nuclear factor (NF)-κB ligand (RANKL), and tartrate-resistant acid phosphatase (TRAP) were detected by ELISA. Culture supernatant and serum levels of calcium were measured using a Plasma Emission Spectrometer. One-way ANOVA was used for statistical analyses. The results showed that administration of puerarin plus zinc prevented the decrease in mandibular BMD and bone morphometrical parameters more effectively than single use of puerarin or zinc (p<0.05), which was similar to the biomechanical tests (p<0.05). Furthermore, puerarin and zinc additively up-regulated OPG, OPN protein levels, Ca ion level and down-regulated RANKL, TRAP protein levels. In conclusion, puerarin and zinc additively prevent mandibular bone loss through inhibiting osteoclastogenesis in ovariectomized rats, which will shed more light on the potential use of puerarin and zinc in the prevention/treatment of oral bone loss clinically.
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    Role of skeletal muscle in mandible development
    (F. Hernández y Juan F. Madrid. Universidad de Murcia: Departamento de Biología Celular e Histología, 2014) Rot, Irena; Mardesic-Brakus, Snjezana; Costain, Willard J.; Saraga-Babic, Mirna; Kablar, Boris
    As a continuation of the previous study on palate development (Rot and Kablar, 2013), here we explore the relationship between the secondary cartilage mandibular condyles (parts of the temporomandibular joint) and the contributions (mechanical and secretory) from the adjacent skeletal musculature. Previous analysis of Myf5-/- :MyoD-/- mouse fetuses lacking skeletal muscle demonstrated the importance of muscle contraction and static loading in mouse skeletogenesis. Among abnormal skeletal features, micrognathia (mandibular hypoplasia) was detected: small, bent and posteriorly displaced mandible. As an example of Waddingtonian epigenetics, we suggest that muscle, in addition to acting via mechanochemical signal transduction pathways, networks and promoters, also exerts secretory stimuli on skeleton. Our goal is to identify candidate molecules at that muscle-mandible interface. By employing Systematic Subtractive Microarray Analysis approach, we compared gene expression between mandibles of amyogenic and wild type mouse fetuses and we identified up- and downregulated genes. This step was followed by a bioinformatics approach and consultation of webaccessible mouse databases. We searched for individual tissue-specific gene expression and distribution, and for the functional effects of mutations in a particular gene. The database search tools allowed us to generate a set of candidate genes with involvement in mandibular development: Cacna1s, Ckm, Des, Mir300, Myog and Tnnc1. We also performed mouse-to-human translational experiments and found analogies. In the light of our findings we discuss various players in mandibular morphogenesis and make an argument for the need to consider mandibular development as a consequence of reciprocal epigenetic interactions of both skeletal and non-skeletal compartments.
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    Unveiling the smallest – systematics, classification and a new subfamily of featherwing beetles based on larval morphology (Coleoptera: Ptiliidae).
    (CSIRO Publishing, 2019) Sörensson, M.; Delgado, Juan A.; Zoología y Antropología Física