Chronic liver injury alters basal and stimulated nitric oxide production and 3H-thymidine incorporation in cultured sinusoidal endothelial cells from rats.
OBJECTIVE
Under pathological conditions the nitric oxide synthase (NOS)-mediated nitric oxide production of sinusoidal endothelial cells might be altered. Therefore, studies were performed to evaluate the nitrite formation by cultured sinusoidal endothelial cells from rat livers chronically injured by thioacetamide and the effect of endogenously or exogenously generated nitric oxide on their proliferative activity.


METHODS
Basal and stimulated nitrite formation, expression of NOS and DNA synthesis were examined in sinusoidal endothelial cells isolated and cultivated from livers with incipient or advanced chemically-induced cirrhosis.


RESULTS
Cultured sinusoidal endothelial cells from injured livers exhibited a reduced basal and an increased lipopolysaccharide-stimulated nitrite production when compared with controls. Western blot analysis revealed a markedly reduced protein expression of endothelial NOS (eNOS) and inducible NOS (iNOS) in sinusoidal endothelial cells from both experimental groups when compared with controls. Lipopolysaccharide stimulated iNOS expression in sinusoidal endothelial cells from control livers only marginally, and from those with cirrhosis more strongly. There was no clear correlation between the amount of enzyme and nitrite formation. Cultured sinusoidal endothelial cells from livers with incipient cirrhosis showed a higher proliferative activity than controls. Endogenously-produced nitric oxide inhibited DNA synthesis in all groups in a cGMP-independent way. Exogenously-generated nitric oxide affected DNA synthesis differently in sinusoidal endothelial cells from controls and injured livers.


CONCLUSIONS
The results provide evidence that cultured sinusoidal endothelial cells from controls and livers with incipient or advanced cirrhosis differ with respect to basal and lipopolysaccharide-stimulated nitrite production. The data can be taken as evidence that in sinusoidal endothelial cells from livers chronically injured by thioacetamide, eNOS and iNOS are aberrantly expressed and differently regulated.
Petermann
H
H
Institute of Pathobiochemistry, Medical Faculty of Friedrich Schiller University Jena, Germany.
Vogl
S
S
Schulze
E
E
Dargel
R
R
D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D004727:Endothelium / Q000378:metabolism / Q000473:pathology; D005260:Female; D008099:Liver / Q000378:metabolism* / Q000473:pathology; D008106:Liver Cirrhosis, Experimental / Q000139:chemically induced / Q000378:metabolism* / Q000473:pathology; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase / Q000096:biosynthesis*; D052247:Nitric Oxide Synthase Type II; D051381:Rats; D017208:Rats, Wistar; D013853:Thioacetamide; D013936:Thymidine / Q000378:metabolism*; D013997:Time Factors; D014316:Tritium / Q000378:metabolism
D013853:Thioacetamide; D014316:Tritium; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; D013936:Thymidine