Biodistribution and blood clearance of plasmid DNA administered in arginine peptide complexes

BACKGROUND Peptide/DNA complexes have great potential as non-viral methods for gene delivery. Despite promising results for peptide-mediated gene delivery technology, an effective systemic peptide-based gene delivery system has not yet been developed. METHODS This study used pCMV-Luc as a model gene to investigate the biodistribution and the in vivo efficacy of arginine peptide-mediated gene delivery by polymerase chain reaction (PCR). RESULTS Plasmid DNA was detected in all organs tested 1 h after intraperitoneal administration of arginine/DNA complexes, indicating that the arginine/DNA complexes disseminated widely through the body. The plasmid was primarily detected in the spleen, kidney, and diaphragm 24 h post administration. The mRNA expression of plasmid DNA was noted in the spleen, kidney, and diaphragm for up to 2 weeks, and in the other major organs, for at least 1 week. Blood clearance studies showed that injected DNA was found in the blood as long as 6 h after injection. CONCLUSIONS Taken together, our results demonstrated that arginine/DNA complexes are stable in blood and are effective for in vivo gene delivery. These findings suggest that intraperitoneal administration of arginine/DNA complexes is a promising tool in gene therapy.