Intra-articular cross-linked hyaluronic acid-dexamethasone (cHA-Dex) hydrogel injections increased type II collagen (COL II) expression, while it decreased type X collagen (Col X) and matrix metalloproteinase 13 (MMP-13) expressions in cartilage, histologically. Immunohistochemical staining was used for COL II, COL X, and MMP-13. Positive signals are indicated by brown staining. Increased COL II expression (a), and decreased COL X (b) and MMP-13 (c) expressions were detected in the articular cartilage of cHA-Dex gel-treated animals comparing with the ACLT + saline or cHA only groups. The images obtained under the 10×, 20× objective lenses respectively.