Fig. 2

Magnetic resonance imaging (MRI) of knee articular cartilage in normal sheep and in a sheep model of knee osteoarthritis surgically induced by anterior cruciate ligament transection and medial meniscectomy, followed by intra-articular injection of sterile saline (NC) or haMSCs into the right knee joint at 6 weeks (one dose) and 9 weeks (one dose) after surgery. (A) MRI analysis of changes in articular cartilage in different groups. The red arrows, yellow arrowhead, and red arrowhead indicate joint effusion, osteophyte formation, and bone marrow edema. Scale bar: 2 cm. (B) MOCART scores based on MRI results in different groups (three animals per group). *p < 0.05. Abbreviations: NC, negative control; haMSCs, human adipose-derived mesenchymal stem cells