Open AccessOxidative stress and septic shock: metabolic aspects of oxygen‐derived free radicals generated in the liver during endotoxemia
Author(s) -
Sakaguchi Shuhei,
Furusawa Shinobu
Publication year - 2006
Publication title -
fems immunology & medical microbiology
Language(s) - English
Resource type - Journals
eISSN - 1574-695X
pISSN - 0928-8244
DOI - 10.1111/j.1574-695x.2006.00072.x
Subject(s) - oxidative stress , septic shock , lipid peroxidation , lipid peroxide , sepsis , peroxynitrite , nitric oxide , shock (circulatory) , pathogenesis , radical , oxidative phosphorylation , immunology , endocrinology , chemistry , pharmacology , medicine , biochemistry , biology , superoxide , enzyme
This review describes the role of oxidative stress caused by endotoxin challenge in sepsis or septic shock symptoms. We observed that endotoxin injection resulted in lipid peroxide formation and membrane damage (near 60–150 kDa) in the livers of experimental animals, causing decreased levels of scavengers or quenchers of free radicals. The administration of α‐tocopherol completely prevented injury to the liver plasma membrane caused by endotoxin, and suggested that lipid peroxidation by free radicals might occur in a tissue ischemic state, probably by disseminated intravascular coagulation (DIC), in endotoxemia. In mice, depression of Ca 2+ ‐ATPase activity in the liver plasma membrane may contribute to the membrane damage caused by endotoxin, and the increase of [Ca 2+ ] i in the liver cytoplasm may partially explain the oxidative stress that occurs in endotoxemia. It seems that endotoxin‐induced free radical formation is regulated by Ca 2+ mobilization. Moreover, we have suggested that the oxidative stress caused by endotoxin may be due, at least in part, to the changes in endogenous zinc or selenium regulation during endotoxemia. Interestingly, the extent of TNF‐α‐induced oxidative stress may be the result of a synergism between TNF‐α and gut‐derived endotoxin. It is likely that bacterial or endotoxin translocation plays a significant role in TNF‐α‐induced septic shock. On the other hand, although nitric oxide (NO) has been implicated in the pathogenesis of vascular hyporesponsiveness and hypotension in septic shock in our experimental model, it is unlikely that NO plays a significant role in liver injury caused by free radical generation in endotoxemia.