Histopathology of the synovial membrane. A-D, Representative sections of synovial membranes stained with hematoxylin and eosin from healthy rabbits (A), high fat diet (HFD) rabbits (B), chronic antigen-induced arthritis (AIA) rabbits (C), and HFD+AIA rabbits (D), original magnifications x200, scale bar = 50 µm. E, Global synovitis score, quantified as described in materials and methods. Bars show the mean and SEM (n = 7 to 9 rabbits per group). F, Detail of the inflammatory cells observed in the AIA synovium (left side) and in the AIA + HFD synovium (right side), original magnifications x630, scale bar = 25 µm. Inflammatory foam cells of AIA + HFD synovial membrane show an increased size compared with inflammatory cells of AIA synovium.