Suppressive effect of hyaluronan on chondrocyte apoptosis in experimentally induced acute osteoarthritis in dogs

Dogs receiving anterior cruciate ligament transection (ACLT) were treated with either intravenous (IV) or intraarticular (IA) administration of hyaluronan (HA), and differences in appearance of chondrocyte apoptosis of the stifle joint were investigated. Chondrocyte apoptosis was detected using flow cytometry as well as by staining with TdT-mediated dUTP nick end labeling (TUNEL). The percentage of apoptotic chondrocytes in dogs with ACLT was significantly higher than that in intact (non-ACLT) dogs. Dogs treated with IA or IV injection of HA after ACLT had fewer apoptotic chondrocytes than non-treated dogs after ACLT. It was suggested that ACLT-induced apoptosis of chondrocytes was suppressed by HA administration of either IA or IV.