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A Reliable and Reproducible Critical-Sized Segmental Femoral Defect Model in Rats Stabilized with a Custom External Fixator
Published on: March 24, 2019
A murine femoral segmental defect model for bone tissue engineering using a novel rigid internal fixation system
Kai Liu1, Dianqi Li, Xiangyu Huang
1The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, PR China.
The Journal of Surgical Research
|March 26, 2013
Summary
Researchers developed a new internal fixation device for a mouse femur defect model. A 2.0 mm defect size was identified as critical, showing nonunion and suitable for bone regeneration studies.
Area of Science:
- Orthopedics
- Biomedical Engineering
- Animal Models
Background:
- Mice are crucial for bone research, but lack ideal long bone defect models.
- External fixation devices have limitations; internal fixation is preferred for segmental bone defects.
- A simple, reproducible, and standardized murine critical-size defect model is needed.
Purpose of the Study:
- To establish a murine critical-size femoral segmental defect model.
- To design and verify an internal fixation system for this model.
- To determine the critical defect size for nonunion in mouse femurs.
Main Methods:
- An internal plate-and-bolts fixation system was designed using computer-aided analysis of adult C57BL/6 mouse femurs.
- A 1.5 mm or 2.0 mm segmental defect was created in the femoral midshaft of 67 mice.
- Biomechanical stability (compression, bending), X-ray, micro-CT, and histology were used to assess healing and model validity.
Main Results:
- The internal fixation device and surgical procedure had no adverse effects on the mice.
- The bone-implant construct showed biomechanical stability comparable to intact femurs.
- A 2.0 mm defect did not heal (nonunion) within 12 weeks, while bone mineral density remained unaffected.
Conclusions:
- A 2.0 mm femoral segmental defect in C57BL/6 mice, stabilized with the designed internal fixation, represents a critical size defect.
- This model is suitable for bone tissue engineering and bone regeneration research.
- The developed internal fixation system provides a reliable method for creating and studying critical-size defects in mice.
