[Nitric oxide synthase and apoptosis activity in chondrocytes of articular cartilage in posttraumatic knee...

The dynamics of nitric oxide synthase (NOS) and apoptosis activity was studied in the in chondrocytes of articular cartilage of the patients with posttraumatic knee instability. Statistically significant increase of chondrocyte NOS activity was detected in the earliest period after the trauma (1.5 months). This was accompanied by the appearance of a great number of apoptotic cells in the zones of the cartilage with high NOS activity. Remarkably, these changes developed at the same time with statistically significant decrease of total matrix glycosaminoglycan content. These results suggest that there is a NOS-dependent signaling way of apoptosis that could participate in the development of early dystrophic changes in the cartilage.