Role of NF-kappaB activation and nitric oxide expression during PGE protection against d-galactosamine-induced cell death in cultured rat hepatocytes.

Prostaglandin E1 (PGE1) reduces cell death in experimental and clinical liver dysfunction. Nitric oxide (NO) mediates PGE1 protection against D-galactosamine (D-GalN)-induced cell death. Nuclear factor kappa-B (NF-kappaB) plays a protective role in different experimental models of cell death. We investigated if NF-kappaB was responsible for inducible nitric oxide synthase (iNOS) expression and cytoprotection induced by PGE1 against D-GalN cell death in cultured hepatocytes. Rat hepatocytes were isolated following the classical method of collagenase perfusion of liver. A kinetic study of cell death, NF-kappaB activation, mRNA and protein iNOS expression, and NO production was carried in hepatocytes treated with D-GalN (5 mM) in the presence or absence of PGE1 (1 microM) administered 2 h before the hepatotoxin. A proteasome inhibitor was used to evaluate the role of NF-kappaB activation in our experimental conditions. PGE1 protection against D-GalN-induced cell death was associated with its capacity to rapidly enhance NF-kappaB activation, mRNA and protein iNOS expression, and NO production in D-GalN-treated hepatocytes. The inhibition of NF-kappaB activation abolished iNOS expression and cell protection by PGE1 in hepatocytes treated with the hepatotoxin. The present study shows that the cytoprotection by PGE1 against D-GalN-induced apoptosis was related to NF-kappaB-dependent iNOS expression.