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Updated: May 15, 2026
02:56
Creating a Box-Cavity Defect Model in the Cortical Bone of Rat Femora
Published on: November 21, 2023
Calcified cartilage islands in rat cortical bone
Fiona Linnea Bach-Gansmo1, Sarah Catherine Irvine, Annemarie Brüel
1Department of Chemistry and iNANO, Aarhus University, Langelandsgade 140, 8000, Aarhus C, Denmark. flb06@inano.au.dk
Calcified Tissue International
|January 1, 2013
Summary
Rat leg bones contain unique, highly mineralized cartilage islands. These structures, absent in species with extensive bone remodeling, may influence bone
Area of Science:
- Bone biology
- Skeletal development
- Comparative anatomy
Background:
- Rats exhibit minimal haversian remodeling in cortical bone.
- Rat cortical bone formation occurs via endochondral ossification.
- This results in mineralized cartilage islands within the femoral mid-diaphysis.
Purpose of the Study:
- To investigate the mineralization and structural properties of cartilage islands in rat femur.
- To compare these properties with the surrounding cortical bone.
- To explore the potential role of these islands in the lack of haversian remodeling in rats.
Main Methods:
- Quantitative backscattered electron imaging for mineralization assessment.
- Immunostaining for collagen type II to confirm cartilaginous origin.
- Toluidine blue staining and 3D synchrotron X-ray tomographic microscopy for structural analysis.
- Nanoindentation to measure mechanical properties (reduced modulus and hardness).
Main Results:
- Cartilage islands exhibit significantly higher mineralization than surrounding bone.
- Islands are confirmed as cartilaginous and elongated along the femoral axis.
- Nanoindentation shows increased reduced modulus and hardness in islands.
- These islands are distributed centrally from growth plates to mid-femur.
Conclusions:
- Rat femoral cortical bone contains distinct, highly mineralized calcified cartilage islands.
- These islands possess superior mechanical properties compared to adjacent bone.
- The presence and properties of these islands may contribute to the limited haversian remodeling observed in rats.
- This finding offers insights into species-specific differences in bone remodeling and structure.
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