Visualization of the localization of phospholipids in developing rat teeth by matrix-assisted laser desorption/ionization imaging mass spectrometry.

Matrix-assisted laser desorption/ionization imaging mass spectrometry (IMS) is used to comprehensively visualize the spatial distribution of numerous biomolecules. The present study was designed to investigate the distribution of phospholipids in developing rat teeth by IMS to identify the characteristic phospholipid molecules for tooth development, and to evaluate the suitability of tissue preparation methods. Rats at postnatal day 3 were euthanized, and the resected head specimens were either fixed or not fixed with 4% paraformaldehyde (PFA), and decalcified or not decalcified in 10% ethylenediaminetetraacetic acid (EDTA) before being frozen.

Immunohistochemical characterization of the mandibular condyle for type I and II collagen, aggrecan, MMP-9, and MMP-13 in MMP-2-deficient mice.

Mice devoid of matrix metalloproteinase (MMP)-2 due to gene targeting have been reported to show articular cartilage destruction in the knee joint; however, the phenotype of the mandibular condylar cartilage remains unknown. Thus, in the present study, we investigated the mandibular condyle in Mmp2 mice. We obtained and bred Mmp2 mice from the same source as the previous study, and performed genotyping using genomic DNA extracted from finger snips.

The visualization of the mineral and protein distribution in the same histological sections of rat calcified growth plate cartilage.

Objective: To determine whether the combination of scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX) and immunostaining would visualize the mineral and protein distribution in the same histological sections.

Methods: Paraffin sections of fixed rat hindlimbs were processed for SEM-EDX and subsequently for immunofluorescence staining.

Results: The localization of calcium, phosphorus, and carbon with type II collagen could be visualized in the same region of calcified growth plate cartilage on the same section.

Calcification and resorption of mouse Meckel's cartilage analyzed by von Kossa and tartrate-resistant acid phosphatase histochemistry and scanning electron microscopy/energy-dispersive X-ray spectrometry.

Meckel's cartilage is essential for the normal development of the mandible. The fate of the intermediate portion of Meckel's cartilage is unique as most of it disappears soon after birth except for the part that forms the sphenomandibular ligament. The mechanism of the disappearance of Meckel's cartilage is unknown; therefore, this study was designed to investigate the process of Meckel's cartilage degradation, focusing on cartilage matrix calcification and the appearance of chondroclasts.

Three-dimensional visualization of osteoclasts in embryonic mouse mandibles using SEM array tomography.

Objective: Three-dimensional (3-D) images of osteoclasts in vivo have been elusive, due to their large size and intricate morphology. The present study was designed to reconstruct the 3-D morphology of whole osteoclasts in developing mouse mandibles using scanning electron microscopy (SEM) array tomography.

Methods: Mandibles of 16 days post coitum mouse embryos were fixed and embedded in epoxy resin after decalcification.

Degradation of extracellular matrices propagates calcification during development and healing in bones and teeth.

Background: Bone, dentin, and enamel are tissues formed through calcification, a process involving deposition of calcium phosphate minerals on extracellular organic matrices. Calcification, the underlying mechanism of which is unknown, is initiated with mineral deposition followed by advancing of the deposit and subsequent maturation of the mineral crystal.

Highlight: We have reviewed the current knowledge of how calcification proceeds during bone development, bone healing, and enamel and dentin development, based on reported studies.