Deletion of Indian hedgehog alleviates osteoarthritis cartilage damage. (A) Coronal sections of mouse knee joints are shown after Safranin O staining. PMM, partial medial meniscectomy; TM, tamoxifen. (B) Osteoarthritis Research Society International Osteoarthritis Cartilage Histopathology Assessment System (OOCHAS) scores are shown. Data are means ± SD. No TM-PMM, n = 12; TM-PMM, n = 12; TM-Sham, n = 10. *P < 0.0001. In the control groups (No TM-Sham, n = 10; TM-Sham, n = 10; No TM-No Surgery, n = 8; TM-No Surgery, n = 8), there were no significant differences, #P = 0.585.