Fig 8. Timeline for studying the shRNA intratracheal delivery model in mice.

shRNA plasmids were mixed with jetPEI with a N/P ratio of 5. Twenty micrograms of plasmids in 50 μL of carrier were administered intratracheally through a 2.5-mm human otoscope specula placed directly into the trachea. The mice were inoculated with 4×10³ PFU/mL influenza virus 24 hours after shRNA transfection. The body weights of the mice were recorded daily, and the lungs were harvested at the time of death or upon euthanasia at day 14. I.T.: intratracheal.