Perfluorochemical liquid-enhanced adenoviral vector distribution and expression in lungs of spontaneously breathing rodents

Perfluorochemical (PFC) liquids have been shown to improve gas exchange and lung compliance in models of lung injury. We reasoned they may also be useful as a vehicle for gene transfer by improving transgene distribution throughout the lung as well as increasing total transgene expression. We have developed a model for PFC liquid use in spontaneously breathing rodents that obviates the need for intubation and ventilation. Intratracheal instillation of the adenoviral vector Adlac-Z resulted in patchy distribution of β- galactosidase (β-gal) activity as demonstrated using X-gal histochemistry. In contrast, in rats instilled with Adlac-Z followed by instillation of PFC liquid, more uniformly distributed and increased β-gal activity was observed. Activity in distal airway and alveolar epithelium was particularly increased. Quantitative measure of β-gal activity in lung homogenates demonstrated a 3- to 6-fold increase in total activity in lungs of rats receiving Adlac-Z and PFC liquid compared to animals receiving Adlac-Z alone. These studies show that PFC liquids can enhance both the distribution and the total amount of transgene expressed following adenoviral-mediated vector transfer to lungs during spontaneous breathing. Use of PFC liquids may increase the efficacy of gene transfer strategies for treatment of cystic fibrosis and other lung diseases.