In Vivo Transgene Expression in the Pancreas by the Intraductal Injection of Naked Plasmid DNA

Patients with type I diabetes, which is caused by the destruction of pancreatic islets, now require regular therapeutic injections of insulin. The use of transgene therapy represents an alternate and potent strategy for the treatment of type I diabetes. However, only a limited number of studies regarding in vivo gene delivery targeting the pancreas and islets have been reported. Here, we report on the possibility of in vivo transgene expression in the pancreas by the intraductal injection of naked plasmid DNA (pDNA). Gene expression activities were detected in the pancreas of mice after the injection of naked pDNA encoding luciferase into the common bile duct. We then investigated the effects of injection dose, volume, and speed on gene delivery and determined the optimal conditions for the delivery of pDNA to the pancreas. Exogenous luciferase mRNA was detected in the pancreatic islets by reverse transcription PCR analysis. Moreover, no injury was detected in the liver, the common bile duct, or the pancreas over time after the injection. These findings indicate that the intraductal injection of naked pDNA promises to be a useful technique for in vivo gene delivery targeted to pancreatic tissue and islets.