LAUSR

For respiratory research utilizing gene vector delivery to the lung, the size of rodent models has typically necessitated relatively "blind" dosing via the nose, via an endotracheal tube, or through a surgical incision into the trachea. This commonly results in a limited ability to dose specific small regions of the lung reliably, and contributes to high levels of transduction variability between animals. The resultant poor reliability, reproducibility, and high variability compromises statistical capability, and so demands greater animal sample sizes than should be feasible. The first reliable targeted gene vector dosing of small regions in rat lungs has been designed and successfully implemented using a miniature rigid bronchoscope containing a working channel. Using this setup, this technique can currently access airway branches down to at least the fourth generation in the lungs of rats >200 g in body weight, allowing dosing and re-dosing of specific lobes via airway branch points in the lung tree. Here, the protocol for performing this minimally invasive technique is reported, along with the effect of delivering vesicular stomatitis virus G pseudotyped lentivirus to selected lung lobes. Examples of other applications, such as delivery of agar beads, are also shown. It is expected that the availability of this technique will substantially enhance gene vector studies in rat models for a range of lung diseases.