Electroporation-mediated transfer of plasmid DNA encoding IL-10 attenuates orthotopic tracheal allograft stenosis in rats

Abstract

Background Electroporation has been shown to increase the efficacy of intramuscular injection of plasmid DNA, resulting in a higher level of foreign gene expression. Using this technique, we examined the effect of viral IL-10 gene transfer on the prevention of tracheal allograft stenosis in an animal model. Methods On the day of tracheal transplantation, recipient Lewis rats were intramuscularly injected with either plasmid pCAGGS-LacZ or plasmid pCAGGS-viral IL-10, followed immediately by electroporation. Tracheas from Brown Norway donors were transplanted into the backs of Lewis recipients, and the histology of the grafts were assessed 2 and 4 weeks after transplantation. Results The serum level of IL-10 peaked at 2000 pg/ml one day after injection; the level then slowly decreased, but was maintained above 1000 pg/ml until 8 days after injection. At Day 28, the airway lumina of the tracheal allografts were almost completely obliterated by fibroproliferative tissue in the control pCAGGS-LacZ-treated rats. In rats injected once with pCAGGS-viral IL-10, luminal obliteration was significantly decreased compared with the control pCAGGS-LacZ-treated rats (mean luminal opening 46.8% vs 0% p < 0.05). The loss of epithelial cells lining the airway was also decreased in the IL-10-treated group (mean epithelial coverage 42% vs 5% p < 0.05). Multiple injections with pCAGGS-viral IL-10 did not further improve the histological changes. Conclusion IL-10 gene transfer by intramuscular injection using electroporation attenuated tracheal allograft stenosis associated with mild epithelial injury.