BACKGROUND: Endotoxin plays an important role in the progression of alcoholic liver injury. However, the role of endotoxin in acute activation of NF-kappaB by ethanol remains unclear. METHODS: In primary rat hepatocyte cultures treated with ethanol and/or endotoxin, the DNA-binding activity of NF-kappaB in the nuclear extract was estimated by electrophoretic mobility shift assay. After pretreatment of a CYP2E1 inhibitor, 4-methyl pyrazole or diallyl sulfide, NF-kappaB activity was also measured in the same manner. RESULTS: Ethanol or endotoxin caused activation of NF-kappaB in primary rat hepatocytes. Taking 50 mM of ethanol and endotoxin together raised the rapid increase in NF-kappaB activation, but both 100 mM of ethanol and endotoxin treatment reduced the increase. Addition of diallyl sulfide decreased the activity at rapid phase but increased it after 60 min, whereas addition of 4-methyl pyrazole caused no change of the activity at rapid phase but raised it after 60 min. Pretreatment with both endotoxin and a CYP2E1 inhibitor raised the activation of NF-kappaB constantly after ethanol addition. These findings suggest that endotoxin plays a critical role in the metabolism-independent activation of NF-kappaB by ethanol. CONCLUSIONS: Endotoxin raised metabolism-independent activation of NF-kappaB by high ethanol in rat hepatocytes.
BACKGROUND: Endotoxin plays an important role in the progression of alcoholic liver injury. However, the role of endotoxin in acute activation of NF-kappaB by ethanol remains unclear. METHODS: In primary rat hepatocyte cultures treated with ethanol and/or endotoxin, the DNA-binding activity of NF-kappaB in the nuclear extract was estimated by electrophoretic mobility shift assay. After pretreatment of a CYP2E1 inhibitor, 4-methyl pyrazole or diallyl sulfide, NF-kappaB activity was also measured in the same manner. RESULTS:Ethanol or endotoxin caused activation of NF-kappaB in primary rat hepatocytes. Taking 50 mM of ethanol and endotoxin together raised the rapid increase in NF-kappaB activation, but both 100 mM of ethanol and endotoxin treatment reduced the increase. Addition of diallyl sulfide decreased the activity at rapid phase but increased it after 60 min, whereas addition of 4-methyl pyrazole caused no change of the activity at rapid phase but raised it after 60 min. Pretreatment with both endotoxin and a CYP2E1 inhibitor raised the activation of NF-kappaB constantly after ethanol addition. These findings suggest that endotoxin plays a critical role in the metabolism-independent activation of NF-kappaB by ethanol. CONCLUSIONS: Endotoxin raised metabolism-independent activation of NF-kappaB by high ethanol in rat hepatocytes.