Photomicrographs with inflammatory reactions in knee joints of animals from groups 1 to 4. Photomicrographs of knee joints from groups 1 to 4 (H & E staining). N/CIA: group 1 (collagen-induced arthritis (CIA) + normal diet (N)) with synovitis, leukocyte infiltration and moderate cartilage erosions (original magnification ×10). PCpre/CIA: group 2 (CIA + pretreatment with the phosphatidylcholine-enriched diet) with moderate inflammatory reactions and slight damage to the cartilage (original magnification ×10). N/control: group 4 (control group with the normal diet), a knee joint with intact structure (original magnification ×10). PCther/CIA: group 3 (CIA + the phosphatidylcholine-enriched diet started with the clinical onset of the disease) with serious inflammatory reactions, extensive cartilage destruction and subchondral bone damage (original magnification ×10). Group 5 (PCpro/control) is not presented since no relevant difference was found in the histological appearance of the two control groups.