Using Inducible Osteoblastic Lineage-Specific Stat3 Knockout Mice to Study Alveolar Bone Remodeling During Orthodontic Tooth Movement
July 21st, 2023
This study provides a protocol for using inducible osteoblast lineage-specific Stat3 knockout mice to study bone remodeling under orthodontic force and describes methods for analyzing alveolar bone remodeling during orthodontic tooth movement, thus shedding light on skeletal mechanical biology.
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 available. 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 remotely to provide further clues for the potential obligations of OTM model in biomechanical research. Begin by selecting 10 six-week old male mice and placing them into two groups labeled WT and CKO, with five mice in each group. Administer tamoxifen to all the mice every two days for a week.
Prepare a plastic mouse dissection platform as an operating table to immobilize the mice. Attach an elastic band to each rubber post for limb fixation. Tie another thread to the metal rod to hold the upper incisors.
Place the anesthetized mouse in the supine position on the operating table. Use four elastic bands to fix the limbs. One thread attached to the metal rod to hold the upper incisors.
Next, prepare closed coil springs for orthodontic force application. Ligate one end of the prepared spring to the maxillary left first molar. Ensure a stable force of 10 grams by measuring with the dynamometer.
Then ligate the other end to the central incisor using a 0.1 millimeter resin-reinforced steel ligature wire. After the operation, place the mice in a recovery cage. Monitor the mice for two to four hours until they regain sufficient consciousness to maintain sternal recumbent.
Provide a soft diet and observe the mice regularly for complications, administering analgesic drugs as needed. Begin by cutting the skin vertically off the cervical region of the euthanized mice. Separate the head from the body, with the entire skin of the head dissected.
Next, cut off the skin and buccinator muscles from the bilateral angulus oris to the posterior region of the mandible. Completely disconnect the buccal muscles and tendons from the cricoid to remove the mandible. Trim any extra bones to obtain the complete maxillae.
Remove the bone behind the bilateral third molars and peel off the palatal mucosa. Finally, disconnect the orthodontic appliance and cut the bone between the incisors along the median palatine suture to obtain the right and left alveolar bone. Alveolar bone remodeling in the Stat3 deletion in osteoblasts was confirmed by immunofluorescence staining of alveolar bone.
Stereomicroscopy revealed that the orthodontic tooth movement distance of the wild type mice increased on days four, seven and ten. However, the orthodontic tooth movement distance was reduced in the Stat3 knockout mice. Micro CT analysis on day 10 confirmed the reduced movement, indicating that Stat3 deletion decelerated orthodontic tooth movement.
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Overview
This study investigates the mechanism of bone remodeling under mechanical force, specifically during orthodontic tooth movement (OTM). Using inducible osteoblast lineage-specific Stat3 knockout mice, the research aims to elucidate the effects of mechanical stimuli on alveolar bone remodeling.
Key Study Components
Area of Science
- Bone remodeling
- Orthodontics
- Mechanical biology
Background
- Bone remodeling is influenced by mechanical forces.
- Orthodontic tooth movement induces significant bone changes.
- Previous studies focused on gene expression and cellular functions.
- Tracing specific gene functions in vivo during OTM is challenging.
Purpose of Study
- To explore the role of specific genes in bone remodeling during OTM.
- To utilize a time-efficient model for studying mechanical effects on bone.
- To enhance understanding of skeletal mechanical biology for clinical applications.
Methods Used
- Inducible osteoblast lineage-specific Stat3 knockout mice.
- Analysis of alveolar bone remodeling.
- Assessment of mechanical force impacts on bone.
- Comparative analysis with other experimental models.
Main Results
- Identification of gene functions during OTM.
- Insights into the mechanisms of bone response to mechanical stimuli.
- Demonstration of the effectiveness of the knockout mouse model.
- Contribution to the understanding of skeletal biology.
Conclusions
- The study provides a novel approach to studying bone remodeling.
- Findings may inform future clinical treatments in orthodontics.
- Highlights the importance of specific genes in mechanical bone responses.
