Two pathways of the nitric oxide‐induced cytotoxycal action

Nitric oxide is a diffusible messenger with multiple biological functions. We show here that NO‐generating compound, S‐nitrosoglutathione (GSNO) induces apoptosis in human chondrocytes and causes necrosis‐like celt death in human epithelial CaOv cell line. Pretreatment of chondrocytes with low‐dose GSNO or with γ‐interferon enhances their tolerance to the second high‐concentration GSNO exposure. On the contrary, in CaOv cells low‐dose GSNO pretreatment diminishes the resistance and increases cytolysis at the second GSNO exposure. We conclude that human chondrocytes possess specific and inducible mechanism preventing celt killing by nitric oxide.