PURPOSE:This study evaluated the use of electroporation to deliver plasmid DNA encoding for luciferase to the in vivo porcine lung.
METHODS:Six farm pigs (neutered males, weights 25 –30 kg.) underwent medial sternotomy under general endotracheal anesthesia. Luciferase plasmid (pLuc) (0.1 ml per site at 2 mg/ml) was injected in multiple sub-pleural locations, marked with hemoclips, in the upper, middle, and lower lobes of the right lung. Electroporation was administered at specific delivery parameters (field strengths and pulse widths). One site of plasmid delivery without electroporation was made as control following completion of all electroporation. Animals were maintained for 48 hours and underwent injection site excision. An additional site of lung tissue, which had received neither plasmid injection nor electroporation, was excised from the lower lobe. The level of luciferase expression was quantified using commercial firefly luciferase (Sigma, St. Louis, MO). Levels were expressed as pg/mg of tissue. Statistical was carried out with ANOVA and statistical significance was defined as p<0.05.
RESULTS:Pulmonary luciferase expression was significantly increased (p<0.05 versus control) at injection sites of pLuc with electroporation at parameters of 40 V/cm field strength and 150 ms pulse width. Expression at sites with parameters of 20 V/cm and 40 V/cm and 100 ms pulse width were also markedly increased (2 –7X vs control), but did not reach statistical significance (p<0.05).
CONCLUSION:Gene delivery to the in vivo porcine lung has been successfully accomplished. Further study of electroporation as a method of gene delivery to the pulmonary parenchyma is warranted.
CLINICAL IMPLICATIONS:This technique eliminates the risk of viral vectors and may provide a method for therapeutic gene delivery to the lung.
DISCLOSURE:Brian Boone, No Financial Disclosure Information; No Product/Research Disclosure Information