Related Experiment Video
Updated: Apr 19, 2026
Development and Evaluation of a Rat Model of Full-Thickness Cartilage Defects
Published on: May 19, 2023
An Articular Cartilage Repair Model in Common C57Bl/6 Mice
Masatake Matsuoka1, Tomohiro Onodera1, Fumio Sasazawa1
1Department of Orthopaedic Surgery, Hokkaido University Graduate School of Medicine , Sapporo, Japan .
Abstract:
To analyze the genetic and biomolecular mechanisms underlying cartilage repair, an optimized mouse model of osteochondral repair is required. Although several models of articular cartilage injury in mice have recently been established, the articular surface in adult C57Bl/6 mice heals poorly. Since C57Bl/6 mice are the most popular strain of genetically manipulated mice, an articular cartilage repair model using C57Bl/6 mice would be helpful for analysis of the mechanisms of cartilage repair. The purpose of this study was to establish a cartilage repair model in C57Bl/6 mice using immature animals. To achieve this goal, full-thickness injuries were generated in 3-week-old (young), 4-week-old (juvenile), and 8-week-old (adult) C57Bl/6 mice. To investigate the reproducibility and consistency of full-thickness injuries, mice were sacrificed immediately after operation, and cartilage thickness at the patellar groove, depth of the cartilage injury, cross-sectional width, and cross-sectional area were compared among the three age groups. The depth of cartilage injury/cartilage thickness ratio (%depth) and the coefficient of variation (CV) for each parameter were also calculated. At 8 weeks postoperatively, articular cartilage repair was assessed using a histological scoring system. With respect to the reproducibility and consistency of full-thickness injuries, cartilage thickness, depth of cartilage injury, and cross-sectional area were significantly larger in young and juvenile mice than in adult mice, whereas cross-sectional width and %depth were almost equal among the three age groups. CVs of %depths were less than 10% in all groups. With respect to articular cartilage repair, young and juvenile mice showed superior results. In conclusion, we established a novel cartilage repair model in C57Bl/6 mice. This model will be valuable in achieving mechanistic insights into the healing process of the joint surface, as it will facilitate the use of genetically modified mice, which are most commonly developed on a C57Bl/6 background.
Insights
Developing a cartilage repair model in young C57Bl/6 mice enhances study of joint surface healing. This optimized model utilizes immature animals for improved reproducibility and mechanistic insights into cartilage regeneration.
Area of Science:
- Biomedical Engineering
- Regenerative Medicine
- Orthopedics
Background:
- Articular cartilage repair mechanisms are poorly understood in adult C57Bl/6 mice.
- C57Bl/6 mice are crucial for genetic manipulation studies, necessitating a suitable cartilage repair model.
- Existing models show limited healing in adult C57Bl/6 mice.
Purpose of the Study:
- To establish a reproducible and consistent osteochondral repair model in immature C57Bl/6 mice.
- To analyze cartilage repair in young, juvenile, and adult C57Bl/6 mice.
- To facilitate genetic studies of cartilage repair mechanisms.
Main Methods:
- Full-thickness cartilage injuries were created in 3-week-old (young), 4-week-old (juvenile), and 8-week-old (adult) C57Bl/6 mice.
- Injury reproducibility was assessed by measuring cartilage thickness, injury depth, width, and area.
- Articular cartilage repair was evaluated histologically 8 weeks post-injury.
Main Results:
- Young and juvenile mice exhibited significantly larger cartilage thickness, injury depth, and area compared to adults.
- Cross-sectional width and injury depth/thickness ratio were consistent across age groups.
- Coefficient of variation for injury depth/thickness ratio was below 10% in all groups, indicating high reproducibility.
- Histological assessment revealed superior cartilage repair in young and juvenile mice.
Conclusions:
- A novel, reproducible cartilage repair model was successfully established in immature C57Bl/6 mice.
- This model provides a valuable platform for investigating the genetic and biomolecular mechanisms of joint surface healing.
- The model's suitability for genetically modified mice enhances future research in cartilage regeneration.
