Changes in the craniofacial morphology in sclerostin knockout mice

Area of Science:

• Genetics and Molecular Biology
• Craniofacial Development
• Bone Biology

Background:

• Sclerostin, a protein encoded by the Sclerostin gene (Sost), plays a crucial role in bone metabolism and regulation.
• Understanding the role of sclerostin in craniofacial development is essential for comprehending skeletal abnormalities.

Purpose of the Study:

• To investigate the impact of sclerostin deficiency on craniofacial morphology.
• To analyze skeletal changes in the cranium, mandible, and femora of Sost knockout mice.

Main Methods:

• Micro computed tomography (micro-CT) was employed to assess craniofacial morphology in 60-day-old wild-type and Sost^Δ26/Δ26 mice.
• Analysis included ten anatomical landmarks, eight measurement parameters, and total mandibular volume.
• Femoral micro-CT and histological analysis evaluated cancellous bone volume, cortical bone volume, and osteoclast numbers.

Main Results:

• Sost^Δ26/Δ26 mice displayed a significantly smaller neurocranium compared to wild-type controls.
• A significant increase in mandibular length (angular process) and total mandibular volume was observed in Sost^Δ26/Δ26 mice.
• Femora of Sost^Δ26/Δ26 mice showed significantly larger cancellous and cortical bone volumes, with no significant difference in osteoclast numbers.

Conclusions:

• Sclerostin deficiency leads to a reduced neurocranium and augmented mandibular bone in Sost^Δ26/Δ26 mice.
• Increased cancellous and cortical bone volumes in the femora suggest a broader role of sclerostin in skeletal homeostasis.
• The findings highlight sclerostin's critical involvement in regulating craniofacial and appendicular skeletal development.