Hepatotropic growth factors protect hepatocytes during inflammation by upregulation of antioxidative systems

AIM:To investigate effects of hepatotropic growth factors on radical production in rat hepatocytes during sepsis.METHODS:Rat hepatocytes,isolated by collagenase perfusion,were incubated with a lipopolysaccharide(LPS)-containing cytokine mixture of interleukin-1β,tumor necrosis factor-α and interferon-γ to simulate sepsis and either co-incubated or pre-incubated with hepatotropic growth factors,e.g.hepatocyte growth factor,epidermal growth factor and/or transforming growth factor-α.Cells were analyzed for glutathione levels.Culture supernatants were assayed for produc-tion of reactive oxygen intermediates(ROIs) as well as NO2-,NO3-and S-nitrosothiols.To determine cellular damage,release of aspartate aminotransferase(AST) into the culture medium was analyzed.Activation of nuclear factor(NF)-κB was measured by electrophoretic mobility shift assay.RESULTS:Rat hepatocytes treated with the LPS-containing cytokine mixture showed a significant increase in ROI and nitrogen oxide intermediate formation.AST leakage was not significantly increased in cells treated with the LPS-containing cytokine mixture,independent of growth-factor co-stimulation.However,pretreatment with growth factors significantly reduced AST leakage and ROI formation while increasing cellular glutathione.Application of growth factors did not result in increased NF-κB activation.Pretreatment with growth factors further increased formation of NO2-,NO3-and S-nitrosothiols in hepatocytes stimulated with LPS-containing cytokine mixture.Thus,we propose that,together with an increase in glutathione increased NO2-,NO3-formation might shift their metabolism towards non-toxic products.CONCLUSION:Our data suggest that hepatotropic growth factors positively influence sepsis-induced hepatocellular injury by reducing cytotoxic ROI formation via induction of the cellular protective antioxidative systems.