High levels of foreign gene expression in hepatocytes after tail vein injections of naked plasmid DNA

We have previously shown that the intramuscular injection of naked plasmid DNA enables foreign gene expression in muscle. Further studies showed that the intravascular delivery of naked plasmid DNA enables high levels of expr ession not only in muscle but also in hepatocytes. For the liver, this tech nique required injection directly into the liver vessels (portal vein, hepa tic vein, or bile duct) and occlusion of outflow. The present study now dem onstrates that high levels of plasmid DNA expression in hepatocytes can be easily obtained by tail vein injections. The highest levels of expression a re achieved by rapidly injecting the plasmid DNA in large volumes, similar to 2.5 ml. This technique has great potential for a wide variety of laborat ory studies.