Name: Murine Alveolar Bone Specimen Collection
Uploaded: 2023-07-21T12:20:00
Description: Watch this Scientific Journal Video about Murine Alveolar Bone Specimen Collection at JoVE.com

murine alveolar bone specimen collection 

Analyse des Umbaus des Alveolarknochens zur Erforschung der mechanischen Biologie des Skeletts

It is generally known that bone is under constant reconstruction throughout life, in response to mechanical forces according to Wolff&#39;s law1,2. Appropriate mechanical stimulation, such as gravity and daily exercise, maintains bone mass and strength and prevents bone loss by stimulating both osteoblasts and osteoclasts. Osteoclasts, responsible for bone resorption3,4,5,6,7, and osteoblasts, responsible for bone formation8,9,10, maintain bone homeostasis and function jointly in the biological process of bone remodeling. In contrast, in the absence of loading stimuli, as in astronauts under long-term microgravity, bones suffer 10% bone mineral density loss, thus increasing the risk of osteoporosis11,12. Furthermore, noninvasive and convenient mechanical therapies, including orthodontics and distraction osteogenesis, have emerged as treatments for bone diseases13,14. All these have shown that mechanical force plays a critical role in maintaining bone quality and quantity. Recent studies generally analyzed bone remodeling in response to mechanical loading using time-consuming models such as running wheel and tail suspension tests, which usually took 4 weeks or more to simulate force loading or unloading15,16. Therefore, there is demand for a convenient and efficient animal model for studying bone remodeling driven by force loading.
The alveolar bone is the most active in terms of bone remodeling, with a high turnover rate17. Orthodontic tooth movement (OTM), a common treatment for malocclusion, is an artificial process of alveolar bone remodeling in response to mechanical force. However, OTM, which induces rapid bone remodeling18, is also a time-saving way to study the effects of mechanical force on bone remodeling compared with other models with a long experimental period. Therefore, OTM is an ideal model to study bone remodeling under mechanical stimuli. It is noteworthy that the mechanism of alveolar bone remodeling is often time-sensitive, and it is necessary to observe the changes in alveolar bone remodeling at certain time points after modeling. With the dual advantages of temporal and spatial control of DNA recombination and tissue specificity, an inducible conditional gene knockout mouse model is a suitable choice for OTM studies.
Conventionally, OTM-mediated alveolar bone remodeling has been divided into tension zones involving bone formation and pressure zones involving bone resorption19,20,21, which is more detailed but difficult to regulate. Furthermore, Yuri et al. reported that the time of bone formation in OTM differed on the tension and compression sides22. In addition, a previous study had demonstrated that the first molar could initiate wide remodeling of the maxillary alveolar bone under orthodontic force, which was not constrained to the tension and pressure zones23. Therefore, we selected the area located within three roots of M1 in the cross-section of the maxillary bone as the region of interest (ROI) and described methods to assess the activity of osteoblasts and osteoclasts in the same area to evaluate alveolar bone remodeling under OTM.
As a nuclear transcription factor, signal transducer and activator of transcription 3 (STAT3) has been proven critical in bone homeostasis24,25. Previous studies have reported low bone mineral density and recurrent pathological fractures in Stat3-mutant mice26,27. Our previous study demonstrated that deletion of Stat3 in Osx+ osteoblasts caused craniofacial malformation and osteoporosis, as well as spontaneous bone fracture28. Recently, we provided in vivo evidence with an inducible osteoblast-specific Stat3 deletion mouse model (Col1&#945;2CreERT2; Stat3fl/fl, hereafter called Stat3Col1&#945;2ERT2) that STAT3 is critical in mediating the effects of orthodontic force driving alveolar bone remodeling29. In this study, we provide methods and protocols for using inducible osteoblast lineage-specific Stat3 knockout mice to study bone remodeling under orthodontic force and describe methods for analyzing alveolar bone remodeling during OTM, thus shedding light on skeletal mechanical biology.

Autor im Rampenlicht: Vergleich des Umbaus von Alveolen und langen Knochen zur Erforschung des Potenzials des OTM-Modells 

Verwendung von induzierbaren osteoblastischen Abstammungs-spezifischen Stat3-Knockout-Mäusen zur Untersuchung des Alveolarknochenumbaus während kieferorthopädischer Zahnbewegung

Our research focuses on the mechanism of bone remodeling under mechanical force, including alveolar bone and long bones. We try to answer how bones respond to mechanical stimuli to shed new light on skeletal mechanical biology for further clinical treatment. Currently, studies on OTM were limited to gene expression analysis in vivo or cellular function analysis in vitro.To this end, a challenge arose. How to trace and explore the function of specific genes in specific lineages during OTM in vivo? That's why we use inducible conditional knockout mice here.Orthodontic tooth movement, which induces rampant bone remodeling, is a time-saving method to study the effects of mechanical force on bone remodeling compared to other models that have a long experimental period. Our protocol also reveals dynamic alveolar bone remodeling at different time points with inducible gene-specific knockout mice. There are many important cell lineages in the alveolar bone.We aim to trace them and find out their underlying mechanisms during OTM. Furthermore, we will compare the mechanisms between alveolar bone and long bone remodeling to provide further clues for the potential of OTM model in biomechanical research.

Watch this Scientific Journal Video about Murine Alveolar Bone Specimen Collection at JoVE.com

Murine Alveolar Bone Specimen Collection   

Sammlung von murinen Alveolarknochenproben 

Beginnen Sie damit, die Haut vertikal von der Halswirbelsäule der euthanasierten Mäuse abzuschneiden, trennen Sie den Kopf vom Körper, wobei die gesamte Haut des Kopfes präpariert wird. Als nächstes schneiden Sie die Haut und die Buccinator-Muskeln vom bilateralen Angulus oris bis zum hinteren Bereich des Unterkiefers ab. Trennen Sie die bukkalen Muskeln und Sehnen vollständig von den Coracoideus, um den Unterkiefer zu entfernen.Schneiden Sie alle überschüssigen Knochen ab, um den vollständigen Oberkiefer zu erhalten. Entfernen Sie den Knochen hinter den beidseitigen dritten Backenzähnen und ziehen Sie die Gaumenschleimhaut ab. Zum Schluss trennen Sie die kieferorthopädische Apparatur und durchtrennen den Knochen zwischen den Schneidezähnen entlang der mittleren Gaumennaht, um den rechten und linken Alveolarknochen zu erhalten.Der alveoläre Knochenumbau in der STAT3-Deletion in Osteoblasten wurde durch Immunfluoreszenzfärbung des Alveolarknochens bestätigt. Die Stereomikroskopie zeigte, dass die kieferorthopädische Zahnbewegungsdistanz der Wildtyp-Mäuse an den Tagen vier, sieben und zehn zunahm. Die kieferorthopädische Zahnbewegungsdistanz war jedoch bei den STAT3-Knockout-Mäusen reduziert.Die Mikro-CT-Analyse an Tag 10 bestätigte die reduzierte Bewegung, was darauf hindeutet, dass die STAT3-Deletion die kieferorthopädische Zahnbewegung verlangsamte.

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Murine Alveolar Bone Specimen Collection 

Using Inducible Osteoblastic Lineage-Specific Stat3 Knockout Mice to Study Alveolar Bone Remodeling During Orthodontic Tooth Movement

The alveolar bone, with a high turnover rate, is the most actively-remodeling bone in the body. Orthodontic tooth movement (OTM) is a common artificial ...