Histological analysis of infrapatellar fat-pad sections stained with Mallory – Azan from rabbits with antigen-induced arthritis. Rabbits with antigen-induced arthritis (AIA) were treated with daily injections of adrenomedullin (AM) or saline (control) into the knee joint spaces for 20 days. The infrapatellar fat pads were harvested from rabbit knees 21 days after arthritis induction. The tissues were sectioned longitudinally perpendicular to the patella ligament in the middle of the tissue, and were stained with Mallory – Azan. (a) AIA rabbit knee was treated with daily intra-articular injections of 3 μg AM for 20 days. (b) AIA rabbit knee was treated with daily intra-articular injections of 1 ng AM for 20 days. (c) The contralateral knee of (a) was treated with daily intra-articular injections of saline for 20 days. Photographs taken at ×40 magnification. Bar = 500 μm.