(A) Representative toluidine-blue-stained sections of the stifle joints of CPB-deficient (Cpb2−/−; backcrossed >9 generations to the C57BL/6J background) and wild-type C57BL/6J control mice (Cpb2+/+) surgically induced to develop OA by medial meniscectomy. Arrowheads indicate areas of total cartilage loss. Scale bar for the low (top) magnification images, 500 μm; scale bar for the high (bottom) magnification images, 200 μm. (B) Histologic quantification of cartilage degeneration, osteophyte formation, and synovitis in (A). Data represent the mean ± s.e.m; Cpb2−/−, n=4; Cpb2+/+, n=5). *P≤0.05 by Mann-Whitney test.