A comparison of lipoprotein secretion, bile production and hepatic morphology in isolated rat livers perfused with a perfluorocarbon emulsion or rat erythrocytes.
Isolated rat livers were perfused with an oxygenated perfluorocarbon emulsion, FC-43 emulsion for 1 to 4 hr. FC-43 emulsion contained 20% FC-43 (wt/vol) perfluorotributylamine (the fluorocarbon component for the transport of oxygen and carbon dioxide) emulsified with 2.56% Pluronic F-68 (a nonionic surfactant) in Krebs-Ringer bicarbonate buffer. FC-43 emulsion also contained 3% hydroxyethyl starch as an oncotic agent and 1.8 mg/ml glucose. The viability (oxygen consumption), bile secretion, structural integrity and secretion of nascent lipoproteins by FC-43-perfused rat livers was compared with livers perfused with Krebs-Henseleit bicarbonate buffer that contained rat erythrocytes (25% hematocrit) and 1.5 mg/ml glucose (red blood cell medium). Oxygen consumption was somewhat higher in livers perfused with FC-43 emulsion. Bile secretion of livers perfused with FC-43 emulsion for 4 hr was reduced significantly to 40% of that by red blood cell medium. The structural integrity of livers perfused with FC-43 emulsion varied from normal to marked cellular damage. Light-microscopical examination of rat livers perfused with FC-43 emulsion showed ballooning of sinusoids, presence of vacuoles in sinusoidal lining cells in some hepatocytes and detachment of endothelium in sinusoids. The number of vacuoles progressively increased in longer perfusions. Electron-microscopical studies showed the presence of small (60 to 100 nm) vesicles of varying electron density, presumably fluorocarbon particles inside the vacuoles in sinusoidal lining cells (Kupffer and endothelial) and hepatocytes. After 4 hr of perfusion with FC-43 emulsion, most of the sinusoidal endothelia were denuded, and the microvilli of the hepatocytes all but disappeared. In contrast, the ultrastructure of rat livers perfused with red blood cell medium for 4 hr was unaltered. The accumulation of nascent lipoproteins in perfusates of FC-43-perfused livers was markedly reduced, and no normal very-low-density lipoprotein, low-density lipoprotein or high-density lipoprotein were isolated. Chemical analysis showed the presence of Pluronic F-68 in all lipoprotein fractions. Our data strongly suggest that, during recirculating liver perfusions with FC-43 emulsion (between 1 and 4 hr), the nonionic surfactant detergent Pluronic F-68 dissociated from the emulsion and markedly affected hepatic structure, lipoprotein secretion and the composition of lipoproteins isolated from perfusate. Therefore FC-43 emulsion is not a suitable liver-perfusion medium for studies of lipoprotein metabolism.
Felker
T E
TE
Department of Biophysics, Boston University School of Medicine, Housman Medical Research Center, Massachusetts 02118-2394.
Gantz
D
D
Tercyak
A M
AM
Oliva
C
C
Clark
S B
SB
Small
D M
DM
D000818:Animals; D001646:Bile / Q000378:metabolism*; D004912:Erythrocytes / Q000502:physiology*; D005466:Fluorocarbons; D066298:In Vitro Techniques; D050356:Lipid Metabolism; D008074:Lipoproteins / Q000378:metabolism*; D008099:Liver / Q000033:anatomy & histology / Q000378:metabolism / Q000648:ultrastructure*; D008854:Microscopy, Electron; D009929:Organ Size; D010477:Perfusion; D011506:Proteins / Q000378:metabolism; D051381:Rats
D005466:Fluorocarbons; D008074:Lipoproteins; D011506:Proteins; C008807:perfluorotributylamine