Investigation of Postnatal Craniofacial Bone Development with Tissue Clearing-Based Three-Dimensional Imaging

Area of Science:

• Craniofacial Biology
• Developmental Biology
• Tissue Engineering

Background:

• Traditional 2D methods limit craniofacial bone research due to complex spatial organization.
• A novel tissue clearing method is needed to visualize 3D craniofacial bone development.

Purpose of the Study:

• To develop and apply a novel tissue clearing method for 3D imaging of craniofacial bone development.
• To investigate the spatial relationships of osteogenesis and vasculature during postnatal craniofacial development.
• To compare craniofacial bone development mechanisms with long bone development.

Main Methods:

• Developed the Poly(Ethylene Glycol) Associated Solvent System (PEGASOS) for hard tissue transparency.
• Utilized 3D imaging to visualize craniofacial bone vasculature and osteogenesis.
• Employed fluorescent labeling strategies to track cellular activity and spatial relationships.

Main Results:

• PEGASOS efficiently renders hard tissues transparent while preserving fluorescent signals.
• Craniofacial osteogenesis initially occurs throughout bones, later restricting to sutures and bone marrow.
• Osteogenesis and vasculature show spatial association throughout development, including in adult calvarial bones with Gli1+ mesenchymal stem cells.

Conclusions:

• Craniofacial bones share osteogenesis mechanisms with long bones, despite distinct developmental pathways.
• The PEGASOS method provides a valuable new tool for 3D craniofacial research.
• Understanding spatial relationships is crucial for comprehending craniofacial development and regeneration.