Cathepsin and matrix metalloprotease activity were decreased in Indian hedgehog–deleted mice 2 months after partial medial meniscectomy. Representative images produced with ProSense (A) and MMPSense (B) fluorescent imaging agents (top panels) and summary results (bottom panels) are shown. Data are means ± SD. No tamoxifen–partial medial meniscectomy (TM-PMM), n = 12; TM-PMM, n = 8; and TM-sham, n = 3. *P = 0.016, #P = 0.042.