Figure 1

Attenuation of osteoarthritis development in conplastic (BL/6^NZB) mice following destabilization of the medial meniscus (DMM). Representative Safranin O/Fast green-stained sections of the knee joints (right knee = SHAM; left knee = DMM) of DMM-operated 17-week-old male BL/6^C57 (A) and BL/6^NZB (B) at 8 weeks after surgery. Images show the medial femorotibial compartment of SHAM or DMM-operated knees. Femur (F), tibia (T) as well as anterior (A) and posterior (P) location of the menisci are also represented (magnification 10x). Scale bar, 500 μm. Quantification of cartilage damage in BL/6^C57 (C) and BL/6^NZB (D) mice at 8 weeks following DMM is shown as OARSI score (BL/6^C57 = 9; BL/6^NZB = 10), a semi quantitative scoring system where the minimum value 0 corresponds to the normal cartilage and the maximum value 6 represents a cartilage destruction of more that 75% of the articular surface. Comparison of OARSI score between BL/6^C57 and BL/6^NZB mice after DMM surgery (E). Tissue structure (smooth, fibrillation, undulating), cellularity (normal, hyper cellularity, hypo cellularity), and matrix staining of Safranin O/Fast Green (normal and disrupted staining) were scored and summed together for anterior and posterior menisci. Quantification of anterior meniscus total score of BL/6^C57 (F) and BL/6^NZB (G) after DMM surgery (BL/6^C57 = 8; BL/6^NZB = 6). Comparison of anterior meniscus total score between BL/6^C57 and BL/6^NZB after DMM surgery (H). All data are shown as mean ± SEM; ***p < 0.001, **p < 0.01, *p < 0.05, p = 0.0534 by non-parametric Mann–Whitney test.