Related Experiment Video
Updated: Mar 30, 2026
Destabilization of the Medial Meniscus and Cartilage Scratch Murine Model of Accelerated Osteoarthritis
Published on: July 6, 2022
Histopathological analyses of murine menisci: implications for joint aging and osteoarthritis
1Materials Science and Engineering Program, Department of Mechanical and Aerospace Engineering, University of California, San Diego, USA.
Objective:
To establish a standardized protocol for histopathological assessment of murine menisci that can be applied to evaluate transgenic, knock-out/in, and surgically induced OA models.
Methods:
Knee joints from C57BL/6J mice (6-36 months) as well as from mice with surgically-induced OA were processed and cut into sagittal sections. All sections included the anterior and posterior horns of the menisci and were graded for (1) surface integrity, (2) cellularity, (3) Safranin-O staining distribution and intensity. Articular cartilage in the knee joints was also scored.
Results:
The new histopathological grading system showed good inter- and intra-class correlation coefficients. The major age-related changes in murine menisci in the absence of OA included decreased Safranin O staining intensity, abnormal cell distribution and the appearance of acellular areas. Menisci from mice with surgically-induced OA showed severe fibrillations, partial/total loss of tissue, and calcifications. Abnormal cell arrangements included both regional hypercellularity and hypocellularity along with hypertrophy and cell clusters. In general, the posterior horns were less affected by age and OA.
Conclusion:
A new standardized protocol and histopathological grading system has been developed and validated to allow for a comprehensive, systematic evaluation of changes in aging and OA-affected murine menisci. This system was developed to serve as a standardized technique and tool for further studies in murine meniscal pathophysiology models.
Insights
A new grading system standardizes the histopathological assessment of mouse menisci for aging and osteoarthritis (OA) studies. This protocol enables comprehensive evaluation of meniscal changes in various mouse models.
Area of Science:
- Biomedical research
- Orthopedics
- Histopathology
Background:
- Murine menisci are crucial for studying aging and osteoarthritis (OA).
- Existing methods lack standardization for comprehensive histopathological assessment.
- A validated protocol is needed for evaluating transgenic, knock-out/in, and surgically induced OA models.
Purpose of the Study:
- To establish a standardized protocol for histopathological assessment of murine menisci.
- To develop a grading system applicable to aging, OA, and genetically modified mouse models.
- To enable systematic evaluation of meniscal pathophysiology.
Main Methods:
- Knee joints from C57BL/6J mice (aged 6-36 months) and surgically induced OA models were processed.
- Sagittal sections including anterior and posterior meniscal horns were graded.
- Grading criteria included surface integrity, cellularity, and Safranin-O staining intensity and distribution; articular cartilage was also scored.
Main Results:
- The developed grading system demonstrated good inter- and intra-class correlation coefficients.
- Age-related changes included decreased Safranin-O staining, abnormal cell distribution, and acellular areas.
- Surgically induced OA led to severe fibrillations, tissue loss, calcifications, and abnormal cellularity; posterior horns were generally less affected.
Conclusions:
- A novel, standardized protocol and histopathological grading system for murine menisci has been developed and validated.
- This system allows for comprehensive and systematic evaluation of aging and OA-affected murine menisci.
- The protocol serves as a standardized tool for future research in murine meniscal pathophysiology models.
