Fig. 4

Representative images of meniscus and ligament modifications during post-traumatic OA in DMM joints. a Staining of the contralateral control meniscus. b Toluidine blue staining showed meniscal changes in the DMM mice associated with OA development, including bone formation in the fibrous meniscal attachment site, proteoglycan and bone deposition (red arrow). Col2 deposition was also seen at the sites of high toluidine Blue staining with Sox9-expressing cells (black arrows). c Cruciate ligament insertion site in DMM joints showed areas of strong toluidine blue staining, concomitant with col2 deposition and Sox9 expression. Low mag = low magnification, scale bar = 100 μm; High mag = high magnification, scale bar = 50 μm