THE ISOLATED PERFUSED RAT SPLEEN

Abstract

The aim of this study was to assess directly the function of isolated hepatocytes 1 year after transplantation into the spleen, using an original model of isolated rat-spleen perfusion. Three specific liver functions, albumin synthesis, indocyanine-green clearance, and antipyrine oxidation, were studied. Five .times. 106 isolated hepatocytes were injected into the spleen of syngenic Wistar-Furth rats. One year later, splenectomy was performed, and the splenic pedicle was carefully isolated in order to allow a selective ex vivo perfusion for 3 hr. De novo albumin synthesis was studied by qualitatively using immunoelectrophoresis and autoradiography, and quantitatively using (35S)-methione incorporation in albumin. De novo albumin synthesis was observed in spleens containing transplanted hepatocytes but not in controls (P < 0.001); (35S)-methionine incorporation was signifcantly higher in spleens containing transplanted hepatocytes than in controls (132 .+-. 67 cpm/spleen/hr vs. 14 .+-. 6 cpm/spleen/hr, P < 0.001). Antipyrine clearance was significantly higher in spleens with transplanted hepatocytes than in controls (67.4 .+-. 4.9 .mu.l/min/g vs. 0.2 .+-. 0.4 .mu.l/min/g, P < 0.01). No statistically significant difference was observed with indocyanine-green clearance (4.2 .+-. 6.0 .mu.l/min/g, vs. 5.2 .+-. 5.1 .mu.l/min/g, P > 0.05); this was probably due to the absence of compartmentation between the sinusoid and biliary sectors in this model. In conclusion, using this original isolated rat-spleen perfusion model, it was directly observed that 1 year after transplantation, intrasplenic hepatocytes can perform two liver-specific functions, i.e., de novo albumin synthesis and antipyrine clearance.