A model for directed foreign gene delivery to rat liver cells in vivo

A novel technique for directed delivery of retroviral genes to rat liver cells in vivo is described. Vascular isolation of the liver was achieved in situ and perfusate containing retrovirus expressing the bacterial gene conferring resistance to Hygromycin-B was delivered selectively to the posterior liver lobes. After 15 min, normal blood flow to the liver was restored. The portal venous branch supplying the two anterior liver lobes was ligated either at the same time (Group I, n = 4) or 20 hr prior to perfusion (Group II, n = 4) to stimulate DNA synthesis in the posterior lobes. Controls (Group III, n = 4) were perfused with retrovirus without portal branch ligation. Hepatocyte transduction was assessed 7 days later by isolating the cells and assessing their viability in a selection medium. In Group I and II rats, 9.2 +/- 0.5 and 16.0 +/- 1.0%, respectively, of harvested hepatocytes, expressed the Hygromycin-B gene. In contrast, a significantly smaller number of hepatocytes (2.8 +/- 0.9%, P less than 0.003) expressed the gene in the absence of stimulation of DNA synthesis.