Regulation of macrophage function by the antioxidant N-acetylcysteine in mouse-oxidative stress by endotoxin

Changes in several functions of peritoneal macrophages from mice with oxidative stress caused by intraperitoneal injection of endotoxin (Escherichia coli lipopolysaccharide, LPS) (100 mg/kg), and associated with a high production of reactive oxygen species (ROS), have been observed in our previous studies. Antioxidants such as N-acetylcysteine (NAC) are free radical scavengers that improve and modulate the immune response, especially in oxidative stress situations. Therefore, in the present work, we have studied the effects of the administration of NAC (150 mg/kg i.p.) on different functions of peritoneal macrophages from Swiss mice suffering that oxidative stress, caused by LPS (100 mg/kg). NAC was injected 30 min after LPS injection, and the peritoneal macrophages were obtained at 2, 4, 12, and 24 h after endotoxin injection. The following functions, key stages of the phagocytic process, were studied: adherence to substrate, chemotaxis, ingestion of particles, and production of ROS (reactive oxygen species), as well as tumor necrosis factor (TNFalpha) release. The decrease in chemotaxis and the increase in adherence, ingestion, superoxide anion production, and TNFalpha release shown by macrophages from animals with oxidative stress were counteracted by NAC injection. These data suggest that NAC administration may be useful for the treatment of oxidative stress-linked endotoxic shock, modulating the function of macrophages, specifically in decreasing the production of ROS and of inflammatory cytokines such as TNFalpha.