Fig 1: Icariin treatment promoted the expression of chondrogenic marker genes and inhibited the expression of chondrocyte hypertrophic genes in vivo. (A) The expression of Sox9, collagen type II alpha 1 (COL2A1), collagen type X (ColX), and matrix metalloproteinase 13 (MMP13) in articular cartilage, 12 weeks after murine anterior cruciate ligament transection (ACLT), were detected by immunohistochemical (IHC) staining. (B–E) The quantification of IHC staining of Sox9, Col2a1, ColX, and MMP13 in (A). The three mouse groups include: the sham group (no surgery and joint injection with normal saline), the ACLT + ICA group (ACLT surgery and icariin treatment) and the ACLT group (ACLT surgery and joint injection with normal saline). Data are presented as the mean ±SD. N=5. NS – nonsignificant. * P<0.05; ** P<0.01.