Fig. 3

Safranin O staining of pathological sections of the knee joint of mice in groups. (Scale bar = 100 μm). (A). female control group; (B). ovariectomized group;( C). ovariectomized group supplemented with estrogen; and (D). male group; The blue area represents the subchondral bone, and the red area represents the articular cartilage.F. femour. T. tibia. Sham, sham operation; DMM, medial meniscus instability operation