NADPH oxidase is not an essential mediator of oxidative stress or liver injury in murine MCD diet-induced steatohepatitis.
OBJECTIVE
Hepatic oxidative stress is a key feature of metabolic forms of steatohepatitis, but the sources of pro-oxidants are unclear. The NADPH oxidase complex is critical for ROS generation in inflammatory cells; loss of any one component (e.g., gp91phox) renders NADPH oxidase inactive. We tested whether activated inflammatory cells contribute to oxidant stress in steatohepatitis.


METHODS
gp91phox-/- and wildtype (wt) mice were fed a methionine and choline-deficient (MCD) diet. Serum ALT, hepatic triglycerides, histopathology, lipid peroxidation, activation of NF-kappaB, expression of NF-kappaB-regulated genes and macrophage chemokines were measured.


RESULTS
After 10 days of MCD dietary feeding, gp91phox-/- and wt mice displayed equivalent hepatocellular injury. After 8 weeks, there were fewer activated macrophages in livers of gp91phox-/- mice than controls, despite similar mRNA levels for MCP and MIP chemokines, but fibrosis was similar. NF-kappaB activation and increased expression of ICAM-1, TNF-alpha and COX-2 mRNA were evident in both genotypes, but in gp91phox-/- mice, expression of these genes was confined to hepatocytes.


CONCLUSIONS
A functional NADPH oxidase complex does not contribute importantly to oxidative stress in this model and therefore is not obligatory for induction or perpetuation of dietary steatohepatitis.
dela Peña
Aileen
A
Storr Liver Unit, Westmead Millennium Institute, University of Sydney at Westmead Hospital, NSW, Australia.
Leclercq
Isabelle A
IA
Williams
Jacqueline
J
Farrell
Geoffrey C
GC
D000818:Animals; D018932:Chemokine CCL2 / Q000235:genetics; D054407:Chemokine CCL4; D002794:Choline / Q000008:administration & dosage / Q000378:metabolism; D002796:Choline Deficiency / Q000150:complications*; D051546:Cyclooxygenase 2 / Q000235:genetics; D004032:Diet; D004195:Disease Models, Animal; D005234:Fatty Liver / Q000201:enzymology / Q000209:etiology* / Q000235:genetics; D005260:Female; D005786:Gene Expression Regulation; D006505:Hepatitis / Q000201:enzymology / Q000209:etiology / Q000235:genetics; D018799:Intercellular Adhesion Molecule-1 / Q000235:genetics; D008099:Liver / Q000201:enzymology / Q000378:metabolism; D019402:Macrophage Inflammatory Proteins / Q000235:genetics; D008562:Membrane Glycoproteins / Q000235:genetics / Q000502:physiology*; D008715:Methionine / Q000008:administration & dosage / Q000172:deficiency*; D051379:Mice; D008817:Mice, Mutant Strains; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases / Q000235:genetics / Q000502:physiology*; D016328:NF-kappa B / Q000378:metabolism; D018384:Oxidative Stress / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics
D018932:Chemokine CCL2; D054407:Chemokine CCL4; D019402:Macrophage Inflammatory Proteins; D008562:Membrane Glycoproteins; D016328:NF-kappa B; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D018799:Intercellular Adhesion Molecule-1; D008715:Methionine; D051546:Cyclooxygenase 2; C488842:Cybb protein, mouse; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases; D002794:Choline