Wnt/beta-catenin signaling plays a critical role in bone formation and regeneration. Dentin and cementum share many similarities with bone in their biochemical compositions and biomechanical properties. Whether Wnt/beta-catenin signaling is involved in the dento-alveolar complex formation is unknown. To understand the roles of Wnt/beta-catenin signaling in the dento-alveolar complex formation, we generated conditional beta-catenin activation mice through intercross of Catnb+/lox(ex3) mice with Col1a1-cre mice. In mutant mice, tooth formation and eruption was disturbed. Lower incisors and molars did not erupt. Bone formation was increased in the mandible but tooth formation was severely disturbed. Hypomineralized dentin was deposited in the crown but roots of molars were extremely short and distorted. In the odontoblasts of mutant molars, expression of dentin matrix proteins was obviously downregulated following the activation of beta-catenin whereas that of mineralization inhibitor was increased. Cementum and periodontal ligament were hypoplastic but periodontal space was narrow due to increased alveolar bone formation. While cementum matrix proteins were decreased, bone matrix proteins were increased in the cementum and alveolar bone of mutant mice. These results indicate that local activation of beta-catenin in the osteoblasts and odontoblasts leads to aberrant dento-alveolar complex formation. Therefore, appropriate inhibition of Wnt/beta-catenin signaling is important for the dento-alveolar complex formation.
Animals ; beta Catenin ; Bone Matrix ; Crowns ; Dental Cementum ; Dentin ; Incisor ; Mandible ; Mice ; Molar ; Odontoblasts ; Osteoblasts ; Osteogenesis ; Periodontal Ligament ; Proteins ; Regeneration ; Tooth

PURPOSE: Optical molecular luminescence imaging is widely used for detection and imaging of bio-photons emitted by luminescent luciferase activation. The measured photons in this method provide the degree of molecular alteration or cell numbers with the advantage of high signal-to-noise ratio. To extract useful information from the measured results, the analysis based on a proper quantification method is necessary. In this research, we propose a quantification method presenting linear response of measured light signal to measurement time. MATERIALS AND METHODS: We detected the luminescence signal by using lab-made optical imaging equipment of animal light imaging system (ALIS) and different two kinds of light sources. One is three bacterial light-emitting sources containing different number of bacteria. The other is three different non-bacterial light sources emitting very weak light. By using the concept of the candela and the flux, we could derive simplified linear quantification formula. After experimentally measuring light intensity, the data was processed with the proposed quantification function. RESULTS: We could obtain linear response of photon counts to measurement time by applying the pre-determined quantification function. The ratio of the re-calculated photon counts and measurement time present a constant value although different light source was applied. CONCLUSION: The quantification function for linear response could be applicable to the standard quantification process. The proposed method could be used for the exact quantitative analysis in various light imaging equipments with presenting linear response behavior of constant light emitting sources to measurement time.
Animals ; Bacteria ; Cell Count ; Enzyme Multiplied Immunoassay Technique ; Imidazoles ; Light ; Luciferases ; Luminescence ; Nitro Compounds ; Optical Imaging ; Photons ; Signal-To-Noise Ratio