Canalostomy for Local Drug Delivery into the Inner Ear of an Adult Mouse
Trascrizione
Begin by placing the anesthetized mouse on a pre-heated electric pad. Set the temperature of the electric pad to approximately 37 degrees Celsius. Cover the animal's eyes with eye ointment, then shave the left postauricular region with an electric animal clipper, and disinfect the skin three times with 75% ethanol.
Next place, the animal in the right lateral position to facilitate surgery on the left ear. Make a one to 1.5-centimeter postauricular incision, three millimeters from the left retroauricular groove. Note, when the root of the pinna is defined as the origin, and the plane parallel to the calvarium as 3 to 9 o'clock, the posterior semicircular canal and the lateral semicircular canal are typically located about three millimeters from the root of the pinna between 2 and 3 o'clock.
Bluntly dissect the muscle covering the temporal bone with micro forceps to expose the posterior semicircular canal and lateral semicircular canal, whose margins are clearly visible as dark stripes in the temporal bone. Then, collect a small piece of muscle with micro-forceps, and let it dry.
Next, make a small hole in the middle portion of the posterior semicircular canal using a 26-gauge needle, such that fluid leakage through the hole indicates successful penetration of the bony wall of the posterior semicircular canal. Enlarge the hole to slightly larger than the diameter of the polyamide tubing.
Then, clean the effusion surrounding the whole of the posterior semicircular canal using a cotton pellet. Insert the tip of the polyamide tubing gently into the posterior semicircular canal towards the crus commune to a depth of one to two millimeters.
Start the injection by pressing the 'Run' button on the pump. After the injection, wait two minutes to allow the reagent to spread. Then, remove the injection cannula, and immediately place the muscle into the hole in the posterior semicircular canal.
Return the separated muscles and subcutaneous tissues together. Suture the incision using a 5-0 suture. Disinfect the incision region with povidone-iodine. Finally, after the surgery is complete, position the animal in the right lateral position on an electric pad preheated to 37 degrees Celsius for recovery.
