(A) Experimental timeline. (B) IT instillation setup: the animal was positioned on the rodent workstand (Hollowell EMC, Pittsfield, MA) in the prone position. An otoscope (MDSInc., Valrico, FL) with an attached intubation specula (Hollowell EMC, Pittsfield, MA) was inserted into the pharynx transorally, and a 18G 2.5-inch IV catheter was inserted through the specula into the larynx. The instillate was administered via a syringe attached to the catheter. IT instillation = intratracheal instillation; IV = intravenous.