This research was supported by a grant from the Korea Health Technology R&#38;D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health &#38; Welfare, Republic of Korea (grant number: HI15C2651).

This study was performed in accordance with the Institutional Animal Care and Use Committee of Seoul National University Hospital (14-0148-C1A1), which is accredited by the Association for the Assessment and Accreditation of Laboratory Animal Care International.
NOTE: The experiments were performed on Sprague-Dawley (SD) male rats of 7 - 8 weeks old (200/250 g). Each animal was acclimatized to the laboratory conditions for 1 week prior to the start of the experiment. The animals were housed in...

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Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=MicroRNAs+218a-5p,+219a-5p,+and+221-3p+regulate+vestibular+compensation.">MicroRNAs 218a-5p, 219a-5p, and 221-3p regulate vestibular compensation.</a> Scientific Reports. 7 (1), 8701 (2017).</li><li>Bergquist, F., Ludwig, M., Dutia, M. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Role+of+the+commissural+inhibitory+system+in+vestibular+compensation+in+the+rat.">Role of the commissural inhibitory system in vestibular compensation in the rat.</a> The Journal of Physiology. 586 (18), 4441-4452 (2008).</li><li>Cameron, S. A., Dutia, M. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cellular+basis+of+vestibular+compensation:+changes+in+intrinsic+excitability+of+MVN+neurones.">Cellular basis of vestibular compensation: changes in intrinsic excitability of MVN neurones.</a> NeuroReport. 8 (11), 2595-2599 (1997).</li><li>Park, M. K., Lee, B. D., Lee, J. D., Jung, H. H., Chae, S. 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The authors have nothing to disclose.

This technique is a useful method for creating sudden, permanent, and complete vestibular function loss. This could be used to study vestibular pathologies, such as vestibular neuritis, an acoustic tumor, and Meniere&#39;s disease. Many studies have used this technique to study the neuronal plasticity of vestibular nuclei or the related central process5,17,18,19.
The...

The vestibular organ is essential for balance and eye control. A normal vestibular function depends upon symmetrical afferent signals from the vestibular organs in the two inner ears. Vestibular hypofunction or loss induces dizziness, nystagmus, and postural imbalance. After acute damage, the vestibular function recovers spontaneously within several days, a process known as vestibular compensation1,2. The vestibular compensation of static deficits is a process of recovery related to the imbalance of spontaneous resting activity between the ipsilateral and contralateral vestibular nuclei. The vestibular compensation of dynamic deficits is achieved principally via sensory and behavioral substitutions (using visual or somatosensory inputs)3.These processes are attractive for neuronal plasticity studies4,5.
A number of methods have been developed to study the vestibular system and the mechanisms underpinning neuronal plasticity during vestibular compensation, such as surgical and chemical labyrinthectomy and vestibular neurectomy5,6,7,8. Vestibular neurectomy is a certain way to induce complete vestibular loss, but it is a more difficult and invasive procedure and may induce brain damage8,9. This method requires greater surgical skill and takes more time than labyrinthectomy. Chemical labyrinthectomy including gentamycin, arsanilate, and tetracaine, is easier and can yield reliable results10,11,12. However, the cochlea may also be damaged and vestibular loss may develop over time11. Additionally, the effects of the chemicals on the brain, which should be preserved for accurate evaluation, are unclear. Surgical labyrinthectomy was first introduced in animal studies in 184215 and was first reported in the rat in 193616. This technique has since been used in many animal studies5,17,18,19. Surgical labyrinthectomy is a specific, reliable, and relatively simple method.13,14 Moreover, the symptoms of vestibular damage are seen immediately after surgery. Here, we describe our surgical technique for rat labyrinthectomy.

<table>
	<tbody>
		<tr>
			<td>ASPIRATOR KB-012</td>
			<td>KOH BONG &#38; CO., LTD.</td>
			<td>KB-012</td>
			<td>Medical aspirator</td>
		</tr>
		<tr>
			<td>Blade: #15</td>
			<td>Fine Science Tools</td>
			<td>#10015-00</td>
			<td>Blades for #7 Scalpel Handles, #15</td>
		</tr>
		<tr>
			<td>Carbon Steel Burrs</td>
			<td>Fine Science Tools</td>
			<td>#19007-05</td>
			<td>shaft diameter: 2.3 mm, length: 44 mm, package of 10 burrs</td>
		</tr>
		<tr>
			<td>Carl Zeiss Surgical GmbH</td>
			<td>Carl Zeiss</td>
			<td>#6627100863</td>
			<td>Surgical microscope</td>
		</tr>
		<tr>
			<td>Dumont #3c</td>
			<td>Fine Science Tools</td>
			<td>#11231-20</td>
			<td>Standard tip 0.17 x 0.10 mm, 11 cm</td>
		</tr>
		<tr>
			<td>Dumont #5SF</td>
			<td>Fine Science Tools</td>
			<td>#11252-00</td>
			<td></td>
		</tr>
		<tr>
			<td>Dumont #7B</td>
			<td>Fine Science Tools</td>
			<td>#11270-20</td>
			<td>Serrated 0.17 x 0.10 mm, 11 cm</td>
		</tr>
		<tr>
			<td>Extra Fine Bonn: straight</td>
			<td>Fine Science Tools</td>
			<td>#14084-08</td>
			<td>Iris scissors, best suited for microdissection under high magnification</td>
		</tr>
		<tr>
			<td>Fine Iris Scissors: straight</td>
			<td>Fine Science Tools</td>
			<td>#14094-11</td>
			<td>Made from martensitic stainless steel, combined with molybdenum and vanadium</td>
		</tr>
		<tr>
			<td>Finger Loop Ear Punch</td>
			<td>Fine Science Tools</td>
			<td>#24212-01</td>
			<td>1 mm. Provides stability and control for researchers using the numbering system</td>
		</tr>
		<tr>
			<td>Hartman</td>
			<td>Fine Science Tools</td>
			<td>#13002-10</td>
			<td>Tip width: 1 cm, serrated, 10 cm</td>
		</tr>
		<tr>
			<td>Short Scalpel Handle #7 Solid</td>
			<td>Fine Science Tools</td>
			<td>#10003-12</td>
			<td>#7 short, 12 cm</td>
		</tr>
		<tr>
			<td>Small Vessel Cauterizer</td>
			<td>Fine Science Tools</td>
			<td>#18000-03</td>
			<td>Replacement tip, straight knife, keeps bleeding to a minimum and therefore provides a surgical field clear of clamps and hemostats</td>
		</tr>
		<tr>
			<td>Strong 207S</td>
			<td>SAESHIN</td>
			<td>207S</td>
			<td>Powerful torque at low speed, available with speed or on/off foot controller</td>
		</tr>
		<tr>
			<td>Suction Tubes</td>
			<td>JEUNGDO B&#38;P CO., LTD.</td>
			<td>H-1927-8</td>
			<td>Frazier, 18 cm</td>
		</tr>
		<tr>
			<td>VICRYL</td>
			<td>ETHICON</td>
			<td>W9570T</td>
			<td>Synthetic absorbable sterile surgical suture</td>
		</tr>
		<tr>
			<td>Weitlaner-Locktite</td>
			<td>Fine Science Tools</td>
			<td>#17012-13</td>
			<td>Maximum spread: 4.5 cm, 2 x 3 blunt teeth, 11 cm</td>
		</tr>
		<tr>
			<td>Zoletil</td>
			<td>Virbac, France</td>
			<td></td>
			<td>Tiletamine-zolazepam</td>
		</tr>
		<tr>
			<td>Rompun</td>
			<td>Bayer</td>
			<td></td>
			<td>Xylazine</td>
		</tr>
		<tr>
			<td>Rimadyl</td>
			<td>Pfizer</td>
			<td></td>
			<td>Carprofen</td>
		</tr>
		<tr>
			<td>Septra</td>
			<td>Pfizer</td>
			<td></td>
			<td>Trimethoprim-sulfonamide&#160;</td>
		</tr>
	</tbody>
</table>

surgical labyrinthectomy of the rat to study the vestibular system

To study the vestibular system or the vestibular compensation process, a number of methods have been developed to cause vestibular damage, including surgical or chemical labyrinthectomy and vestibular neurectomy. Surgical labyrinthectomy is a relatively simple, reliable, and rapid method. Here, we describe the surgical technique for rat labyrinthectomy. A postauricular incision is made under general anesthesia to expose the external auditory canal and the tympanic membrane, after which the tympanic membrane and the ossicles are removed without the stapes. The stapes artery, which is located between the stapes and the oval window, is a vulnerable structure and must be preserved to obtain a clear surgical field. A hole to fenestrate the vestibule is made with a 2.1-mm drill bur superior to the stapes. Then, 100% ethanol is injected through this hole and aspirated several times. Meticulous dissection under a microscope and careful bleeding control are essential to obtain reliable results. Symptoms of vestibular loss, such as nystagmus, head tilting, and a rolling motion, are seen immediately after surgery. The rotarod or rotation chair test can be used to objectively and quantitatively evaluate the vestibular function.

The success of the surgery was validated by behavioral tests. All animals exhibited the typical behavior of a unilateral loss of vestibular function. Spontaneous barrel-rolling was evident immediately after surgery, being evoked by an air puff over the head or a light touch to the body in the early recovery phase (Video 1). 3 d after surgery, the animals moved around leaning toward the lesioned side with occasional falls to the left side. Spontaneous nystagmus was observe...

Watch this Scientific Journal Video about Surgical Labyrinthectomy of the Rat to Study the Vestibular System at JoVE.com

Surgical Labyrinthectomy of the Rat to Study the Vestibular System

This protocol describes the surgical labyrinthectomy of a rat, which is a useful method for studying the vestibular system.

To study the vestibular system or the vestibular compensation process, a number of methods have been developed to cause vestibular damage, including ...

The overall goal of surgical labyrinthectomy in the rat is to study the vestibular system and vestibular compensation processes. This method can have acute complications regarding the vestibular compensation process of the vestibular function loss. The main advantage of this technique is that it is a simple labor and rapid method.Generally, individuals new to this method will struggle to preserve the stapes artery. Because the stapes artery is close to the drilling site. Begin by covering autoclaved surgical instruments with a sterile pad and disinfect the operating area with seventy percent ethanol.After anesthetizing the rat using an institutionally approved method, place the rat on a warming pad set at 42 degrees Celsius. Apply lubricant eye ointment to both eyes of the rat to prevent eye dryness while under anesthesia. Place the rat on its right side.Then, shave the fur over the surgical area, and disinfect the site with seventy percent ethanol. Place a sterile drape and maintain sterile conditions during the surgery. Inject one percent lidocaine hydrochloride subcutaneously into the left retroauricular area.Then, after using a number fifteen scalpel blade to make a five centimeter retroauricular incision, use iris scissors to separate the muscle and fascia and expose the external auditory canal. Then, slightly open the external auditory canal and widely expose the tympanic membrane. Use forceps to remove the tympanic membrane and the ossicles except for the stapes.Use iris scissors or the number fifteen blade to detach the muscles on the lambdoidal ridge. Use a drill fitted with a two point one millimeter cutting and two point one and one point four millimeter diamond burr, to drill the tympanic bulla bone around the point of exit of the facial nerve at low speed. Take a moment to identify the stapedial artery.This is the single most critical step. Careful handling of the drill is essential. Be careful not to damage the stapedial artery during the drilling process.Continue drilling the vestibule superior to the stapedial artery, and expose the round window and the bony lateral semicircular canal. Open the lateral semicircular canal near its ampulla, then continue drilling in the plane of the lateral semicircular canal, to drill the ampulla of the superior semicircular canal. Use an eighteen gauge or twenty-two gauge needle to aspirate the contents of the vestibule.Then inject and aspirate one cubic centimeter of one hundred percent ethanol three times. Close the muscles and the skin in two layers with simple interrupted sutures. Monitor the rat and keep it warm until it wakes.Once the rat regains sternal recumbancy, return it to the housing room. Spontaneous barrel rolling was evident in a Sprague-Dawley rat that underwent labyrinthectomy two days prior. It could be evoked by light touch in the early recovery phase.Spontaneous nystagmus was also present in the post-labyrinthectomy rat. After watching this video, you should have a good understanding of the anatomy of the middle ear and labyrinth. Once mastered, this technique can be done in twenty minutes if it is performed properly.

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9.8K 조회수.  Chung-Ang University College of Medicine. The overall goal of surgical labyrinthectomy in the rat is to study the vestibular system and vestibular compensation processes. This method can have acute complications regarding the vestibular compensation process of the vestibular function loss. The main advantage of this technique is that it is a simple labor and rapid method.Generally, individuals new to this method will struggle to preserve the stapes artery. Because the stapes artery is close to the drilling site. Begin by cover...