1. The OARSI histopathology initiative – recommendations for histological assessments of osteoarthritis in the rabbit 
S. Laverty, C.A. Girard, J.M. Williams, E.B. Hunziker, K.P.H. Pritzker 
Osteoarthritis and Cartilage 
Volume 18, Pages S53-S65 (October 2010)
DOI: /j.joca
Copyright © 2010 Osteoarthritis Research Society International Terms and Conditions

2. Fig. 1
Representative macroscopic changes of the articular cartilage. India ink particles are absorbed to the cartilage surface or trapped in fissures and indicate areas of fissures. With full depth erosion of all cartilage zones, the bone appears as a pale area surrounded by India ink stained cartilage, highlighting fissures in cartilage contiguous to the erosion. Bar=1cm. (A) Score 1: Intact surface: surface normal in appearance and does not retain India ink. (B) Score 2: 0mm<Fissures ≤4mm, (C) Score 3: 4mm<Fissures ≤8mm. (D) Score 4: 8mm≤Fissures. (E) Score 5: 0mm<Full depth erosion of cartilage to bone ≤2mm. (F) Score 6: 2mm<Full depth erosion of cartilage to bone ≤5mm. (G) Score 7: 5mm<Full depth erosion of cartilage to bone.
Osteoarthritis and Cartilage  , S53-S65DOI: ( /j.joca )
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3. Fig. 2
Representative articular cartilage histopathology. Representative Safranin O–fast green stained cartilage sections from a rabbit with OA, demonstrating scores corresponding to the recommended histochemical/histological grading system outlined in Table V. The images provided reflect focal changes for most parameters. The numbers in parentheses reflect that the scores take into account the extent of articular surface involvement when assessing Safranin O–fast green staining or structure (The complete articular surface is not included in the atlas.) Similarly in the case of chondrocyte density the numbers in parentheses reflect when observed changes are multifocal (2) or multifocal confluent (3) (see definitions of terminology employed provided with Table V).
Osteoarthritis and Cartilage  , S53-S65DOI: ( /j.joca )
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4. Fig. 3
Representative synovial membrane histopathology. (A) Normal synovial membrane. (B) Normal synovial membrane with underlying adipose cells. (C) Moderate synoviocytes proliferation and slight hyperplasia, with moderate diffuse lymphoplasmacytic infiltration, slight villous hyperplasia and severe fibroblast proliferation, and moderate proliferation of blood vessels. Many cells contain hemosiderin pigments. (D) Severe hyperplasia of synoviocytes, some of which presenting apical cytoplasmic protrusions. A slight diffuse lymphoplasmacytic infiltrate is also present. (E) Severe hyperplasia and hypertrophy of synoviocytes, with slight diffuse lymphoplasmacytic infiltration, proliferation of fibroblasts and moderate proliferation of blood vessels. Many cells contain hemosiderin pigments. (F) Severe hyperplasia and hypertrophy of synoviocytes with slight lymphoplasmacytic infiltrate, severe proliferation of fibroblasts and blood vessels. (G) Perivascular lymphoplasmacytic infiltrate. (H) Lymphoplasmacytic follicle. (I) Severe hyperplasia and hypertrophy of the synoviocytes, with presence of some apical cytoplasmic projections. (J) A probable cartilage matrix detritus is partially embedded in the synovial membrane. Macrophages containing hemosiderin are also present. (K) A bone matrix piece (arrow) is embedded partially in the synovium. The synovial cells are slightly hyperplastic and hypertrophic. (L) Marked hemosiderosis with many macrophages containing hemosiderin. The synoviocytes are slightly hypertrophic. A moderate proliferation of fibroblasts and a severe proliferation of blood vessels are also present.
Osteoarthritis and Cartilage  , S53-S65DOI: ( /j.joca )
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5. Fig. 4
Osteophytes on the distal femur. Extensive osteophyte production (between arrows) on the distal femur abaxial to the trochlear groove.
Osteoarthritis and Cartilage  , S53-S65DOI: ( /j.joca )
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6. Fig. 5
Meniscal changes with OA. (A) Normal meniscus. (B) Moderate surface fissures (between arrows). Grade 3 meniscal change. Visualization enhanced by application of India ink. (C) Meniscus with complete tear. Grade 5 meniscal change and extensive tissue remodelling.
Osteoarthritis and Cartilage  , S53-S65DOI: ( /j.joca )
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7. Fig S1
Representative Safranin O stained cartilage sections from rabbit OA models demonstrating characteristic pathology. (A) Normal articular cartilage from the femoral condyle. (B) Cartilage from the tibial plateau. There is a loss of staining in the upper 1/3 hyaline cartilage of the most of the plateau (score 2), with a focal decrease in chondrocytes (score 1). The structure is however normal (score 0) and no clusters are present (score 0). The total score for this slide is 3. (C) Articular cartilage from the tibial plateau. There is a discrete diffuse loss of staining of the upper 1/3 of hyaline cartilage (score 2), without loss of chondrocytes (score 0). Only one superficial fissure is observed (score 2) and no clusters are present (score 0). The total score for the slide is 4. (D) Articular cartilage from the femoral condyle. There is a diffuse loss of staining in the upper 1/3 of the hyaline cartilage (score 2), and a multifocal decrease in chondrocyte density (score 2). The surface presents irregularities (score 1) but no clusters are present (score 0). The global score for this slide is 5. (E) Articular cartilage from the tibial plateau. There is a diffuse loss of staining of the superficial cartilage (score 2), a multifocal confluent decrease of chondrocytes (score 3). The upper 1/3 of the hyaline cartilage is eroded but for less than 50% of the surface (score 4) but no clusters are present. The total score for this slide is 9. (F) Articular cartilage from the femoral condyle. There is a diffuse loss of staining of the superficial cartilage (score 2), with surface irregularities, some fissures and erosion of the superficial hyaline cartilage over less than 50% of the surface (score 4) (not on photo), multifocal confluent decrease in chondrocytes (score 3) and more than eight clusters (score 3) (not on photo). The total score for the slide is 12. (G) Articular cartilage from the tibial plateau There is loss of staining of the 2/3 of the hyaline cartilage over less than 50% of the surface (score 3), associated with a focal erosion extending to 2/3 of the hyaline cartilage (score 6). There is a multifocal confluent loss of chondrocytes (score 3) without cluster formation (score 0). The total score for the slide is 12. (H) Articular cartilage from the tibial plateau There is a focal loss of staining of the hyaline cartilage (score 5), with a focal erosion of the upper 1/3 of the hyaline cartilage of less the 50% of the surface (score 4), multifocal confluent loss of chondrocytes (score 3) and rare clusters (score 1). The total score for the slide is 13. (I) Articular cartilage from the femoral condyle. There is a diffuse loss of staining of the upper 2/3 hyaline cartilage (score 4), with multifocal confluent decrease of chondrocytes (score 3), erosion of the upper 1/3 hyaline cartilage of less than 50% of the surface (score 4) and presence of numerous clusters (score 3). The total score for this slide is 14. (J) Articular cartilage from the femoral condyle. There is an extensive loss of staining in the upper 2/3 of the hyaline cartilage of less than the half of the condyle (score 3) and a multifocal confluent decrease in cells (score 3), associated with erosion of the upper 2/3 of the hyaline cartilage in less than 50% of the surface (score 6) and presence of numerous clusters (score 3). The global score for this slide is 15. (K) Articular cartilage from tibial plateau. There is a focal loss of staining of the hyaline cartilage, extending to the calcified zone (score 5), with severe loss of chondrocytes (score 4), focal erosion of upper 2/3 of the hyaline cartilage (score 6) and some clusters (score 2). The total score of this slide is 17. (L) Articular cartilage from the femoral condyle. There is an extensive loss of staining in the upper 2/3 of the cartilage (score 4), associated with a diffuse loss of chondrocytes (score 4), erosion extending close to the calcified cartilage on more than 50% of the surface (score 9) with many chondrones (score 3). The total score for this slide is 20.
Osteoarthritis and Cartilage  , S53-S65DOI: ( /j.joca )
Copyright © 2010 Osteoarthritis Research Society International Terms and Conditions