Name: surgical labyrinthectomy of the rat to study the vestibular system
Uploaded: 2018-05-19T13:00:00
Description: Watch this Scientific Journal Video about Surgical Labyrinthectomy of the Rat to Study the Vestibular System at JoVE.com

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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P., Goshgarian, H. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vestibular+compensation+after+labyrinthectomy+and+vestibular+neurectomy+in+cats.">Vestibular compensation after labyrinthectomy and vestibular neurectomy in cats.</a> Otolaryngology-Head and Neck Surgery. 104 (1), 14-19 (1991).</li><li>Vignaux, G., 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=Evaluation+of+the+chemical+model+of+vestibular+lesions+induced+by+arsanilate+in+rats.">Evaluation of the chemical model of vestibular lesions induced by arsanilate in rats.</a> Toxicology and Applied Pharmacology. 258 (1), 61-71 (2012).</li><li>Berryhill, W. E., Graham, M. 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L., Raffai, G., Feher, E., Schaming, G., Monos, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+simple+standard+technique+for+labyrinthectomy+in+the+rat:+a+methodical+communication+with+a+detailed+description+of+the+surgical+process.">A simple standard technique for labyrinthectomy in the rat: a methodical communication with a detailed description of the surgical process.</a> Physiology International. 103 (3), 354-360 (2016).</li><li>Hitier, M., Besnard, S., Vignaux, G., Denise, P., Moreau, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+ventrolateral+surgical+approach+to+labyrinthectomy+in+rats:+anatomical+description+and+clinical+consequences.">The ventrolateral surgical approach to labyrinthectomy in rats: anatomical description and clinical consequences.</a> Surgical and Radiologic Anatomy. 32 (9), 835-842 (2010).</li><li>Flourens, M. 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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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W., Burton, T. J., Dababneh, E., Quail, S. L., Camp, A. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Behavioral+assessment+of+the+aging+mouse+vestibular+system.">Behavioral assessment of the aging mouse vestibular system.</a> Journal of Visualized Experiments. (89), e51605 (2014).</li><li>de Jeu, M., De Zeeuw, C. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Video-oculography+in+mice.">Video-oculography in mice.</a> Journal of Visualized Experiments. 65 (65), e3971 (2012).</li></ol>

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.

surgical-labyrinthectomy-of-the-rat-to-study-the-vestibular-system

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Medicine

Orthotopic Aortic Transplantation: A Rat Model to Study the Development of Chronic Vasculopathy

Research models of chronic rejection are essential to investigate pathobiological and pathophysiological processes during the development of transplant vasculopathy (TVP).
The commonly used animal model for cardiovascular chronic rejection studies is the heterotopic heart transplant model performed in laboratory rodents. This model is used widely in experiments since Ono and Lindsey (3) published their technique. To analyze the findings in the blood vessels, the heart has to be sectioned and all vessels have to be measured.
Another method to investigate chronic rejection in cardiovascular questionings is the aortic transplant model (1, 2). In the orthotopic aortic transplant model, the aorta can easily be histologically evaluated (2). The PVG-to-ACI model is especially useful for CAV studies, since acute vascular rejection is not a major confounding factor and Cyclosporin A (CsA) treatment does not prevent the development of CAV, similar to what we find in the clinical setting (4). A7-day period of CsA is required in this model to prevent acute rejection and to achieve long-term survival with the development of TVP.
This model can also be used to investigate acute cellular rejection and media necrosis in xenogeneic models (5).

This video demonstrates the orthotopic aortic transplant model as a simple model to study the development of transplant vasculopathy (TVP) in rats.

Research models of chronic rejection are essential to investigate pathobiological and pathophysiological processes during the development of transplant ...

An In Vitro System to Study Tumor Dormancy and the Switch to Metastatic Growth

Recurrence of breast cancer often follows a long latent period in which there are no signs of cancer, and metastases may not become clinically apparent until many years after removal of the primary tumor and adjuvant therapy. A likely explanation of this phenomenon is that tumor cells have seeded metastatic sites, are resistant to conventional therapies, and remain dormant for long periods of time 1-4.
The existence of dormant cancer cells at secondary sites has been described previously as quiescent solitary cells that neither proliferate nor undergo apoptosis 5-7. Moreover, these solitary cells has been shown to disseminate from the primary tumor at an early stage of disease progression 8-10 and reside growth-arrested in the patients' bone marrow, blood and lymph nodes 1,4,11. Therefore, understanding mechanisms that regulate dormancy or the switch to a proliferative state is critical for discovering novel targets and interventions to prevent disease recurrence. However, unraveling the mechanisms regulating the switch from tumor dormancy to metastatic growth has been hampered by the lack of available model systems.
in vivo and ex vivo model systems to study metastatic progression of tumor cells have been described previously 1,12-14. However these model systems have not provided in real time and in a high throughput manner mechanistic insights into what triggers the emergence of solitary dormant tumor cells to proliferate as metastatic disease. We have recently developed a 3D in vitro system to model the in vivo growth characteristics of cells that exhibit either dormant (D2.OR, MCF7, K7M2-AS.46) or proliferative (D2A1, MDA-MB-231, K7M2) metastatic behavior in vivo . We demonstrated that tumor cells that exhibit dormancy in vivo at a metastatic site remain quiescent when cultured in a 3-dimension (3D) basement membrane extract (BME), whereas cells highly metastatic in vivo readily proliferate in 3D culture after variable, but relatively short periods of quiescence. Importantly by utilizing the 3D in vitro model system we demonstrated for the first time that the ECM composition plays an important role in regulating whether dormant tumor cells will switch to a proliferative state and have confirmed this in in vivo studies15-17. Hence, the model system described in this report provides an in vitro method to model tumor dormancy and study the transition to proliferative growth induced by the microenvironment.

An In Vitro System to Study Tumor Dormancy and the Switch to Metastatic Growth

A modified 3-D in vitro system is presented in which growth characteristics of several tumor cell lines in reconstituted basement membrane correlate with the dormant or proliferative behavior of the tumor cells at a metastatic secondary site in vivo.

Recurrence of breast cancer often follows a long latent period in which there are no signs of cancer, and metastases may not become clinically apparent ...

Utilizing Transcranial Magnetic Stimulation to Study the Human Neuromuscular System

Transcranial magnetic stimulation (TMS) has been in use for more than 20 years 1, and has grown exponentially in popularity over the past decade. While the use of TMS has expanded to the study of many systems and processes during this time, the original application and perhaps one of the most common uses of TMS involves studying the physiology, plasticity and function of the human neuromuscular system. Single pulse TMS applied to the motor cortex excites pyramidal neurons transsynaptically 2 (Figure 1) and results in a measurable electromyographic response that can be used to study and evaluate the integrity and excitability of the corticospinal tract in humans 3. Additionally, recent advances in magnetic stimulation now allows for partitioning of cortical versus spinal excitability 4,5. For example, paired-pulse TMS can be used to assess intracortical facilitatory and inhibitory properties by combining a conditioning stimulus and a test stimulus at different interstimulus intervals 3,4,6-8. In this video article we will demonstrate the methodological and technical aspects of these techniques. Specifically, we will demonstrate single-pulse and paired-pulse TMS techniques as applied to the flexor carpi radialis (FCR) muscle as well as the erector spinae (ES) musculature. Our laboratory studies the FCR muscle as it is of interest to our research on the effects of wrist-hand cast immobilization on reduced muscle performance6,9, and we study the ES muscles due to these muscles clinical relevance as it relates to low back pain8. With this stated, we should note that TMS has been used to study many muscles of the hand, arm and legs, and should iterate that our demonstrations in the FCR and ES muscle groups are only selected examples of TMS being used to study the human neuromuscular system.

Transcranial magnetic stimulation (TMS) is a non-invasive tool to gain insight on the physiology and function of the human nervous system. Here, we present our TMS techniques to study cortical excitability of the upper limb and lumbar musculature.

Transcranial magnetic stimulation (TMS) has been in use for more than 20 years 1, and has grown exponentially in popularity over the past decade.  While ...

Use of Animal Model of Sepsis to Evaluate Novel Herbal Therapies

Sepsis refers to a systemic inflammatory response syndrome resulting from a microbial infection. It has been routinely simulated in animals by several techniques, including infusion of exogenous bacterial toxin (endotoxemia) or bacteria (bacteremia), as well as surgical perforation of the cecum by cecal ligation and puncture (CLP)1-3. CLP allows bacteria spillage and fecal contamination of the peritoneal cavity, mimicking the human clinical disease of perforated appendicitis or diverticulitis. The severity of sepsis, as reflected by the eventual mortality rates, can be controlled surgically by varying the size of the needle used for cecal puncture2. In animals, CLP induces similar, biphasic hemodynamic cardiovascular, metabolic, and immunological responses as observed during the clinical course of human sepsis3. Thus, the CLP model is considered as one of the most clinically relevant models for experimental sepsis1-3.
Various animal models have been used to elucidate the intricate mechanisms underlying the pathogenesis of experimental sepsis. The lethal consequence of sepsis is attributable partly to an excessive accumulation of early cytokines (such as TNF, IL-1 and IFN-&gamma;)4-6 and late proinflammatory mediators (e.g., HMGB1)7. Compared with early proinflammatory cytokines, late-acting mediators have a wider therapeutic window for clinical applications. For instance, delayed administration of HMGB1-neutralizing antibodies beginning 24 hours after CLP, still rescued mice from lethality8,9, establishing HMGB1 as a late mediator of lethal sepsis. The discovery of HMGB1 as a late-acting mediator has initiated a new field of investigation for the development of sepsis therapies using Traditional Chinese Herbal Medicine. In this paper, we describe a procedure of CLP-induced sepsis, and its usage in screening herbal medicine for HMGB1-targeting therapies.

Sepsis refers to a systemic inflammatory response syndrome resulting from a microbial infection, and can be simulated by a surgical technique termed cecal ligation and puncture (CLP). Here we describe a method to use CLP-induced animal model to screen medicinal herbs for therapeutic agents.

Sepsis refers to a systemic inflammatory response syndrome resulting from a microbial infection. It has been routinely simulated in animals by several ...

Using Saccadometry with Deep Brain Stimulation to Study Normal and Pathological Brain Function

The oculomotor system involves a large number of brain areas including parts of the basal ganglia, and various neurodegenerative diseases including Parkinson's and Huntington's can disrupt it. People with Parkinson's disease, for example, tend to have increased saccadic latencies. Consequently, the quantitative measurement of saccadic eye movements has received considerable attention as a potential biomarker for neurodegenerative conditions. A lot more can be learned about the brain in both health and disease by observing what happens to eye movements when the function of specific brain areas is perturbed. Deep brain stimulation is a surgical intervention used for the management of a range of neurological conditions including Parkinson's disease, in which stimulating electrodes are placed in specific brain areas including several sites in the basal ganglia. Eye movement measurements can then be made with the stimulator systems both off and on and the results compared. With suitable experimental design, this approach can be used to study the pathophysiology of the disease being treated, the mechanism by which DBS exerts it beneficial effects, and even aspects of normal neurophysiology.

This paper describes the use of quantitative measurement of eye movements in conjunction with stimulation of focal areas of the deep brain in order to study physiology, pathophysiology, and the mechanisms of deep brain stimulation.

The oculomotor system involves a large number of brain areas including parts of the basal ganglia, and various neurodegenerative diseases including ...

Using Retinal Imaging to Study Dementia

The retina offers a unique &#8220;window&#8221; to study pathophysiological processes of dementia in the brain, as it is an extension of the central nervous system (CNS) and shares prominent similarities with the brain in terms of embryological origin, anatomical features and physiological properties.&#160; The vascular and neuronal structure in the retina can now be visualized easily and non-invasively using retinal imaging techniques, including fundus photography and optical coherence tomography (OCT), and quantified semi-automatically using computer-assisted analysis programs. Studying the associations between vascular and neuronal changes in the retina and dementia could improve our understanding of dementia and, potentially, aid in diagnosis and risk assessment.&#160; This protocol aims to describe a method of quantifying and analyzing retinal vasculature and neuronal structure, which are potentially associated with dementia. This protocol also provides examples of retinal changes in subjects with dementia, and discusses technical issues and current limitations of retinal imaging.

The retina shares prominent similarities with the brain and thus represents a unique window to study vasculature and neuronal structure in the brain non-invasively. This protocol describes a method to study dementia using retinal imaging techniques. This method can potentially aid in diagnosis and risk assessment of dementia.

The retina offers a unique &#8220;window&#8221; to study pathophysiological processes of dementia in the brain, as it is an extension of the central ...

A Rat Lung Transplantation Model of Warm Ischemia/Reperfusion Injury: Optimizations to Improve Outcomes

From our experience with rat lung transplantation, we have found several areas for improvement. Information in the existing literature regarding methods for choosing appropriate cuff sizes for the pulmonary vein (PV), pulmonary artery (PA), or bronchus (Br) are varied, thus making the determination of proper cuff size during rat lung transplantation an exercise of trial and error. By standardizing the cuffing technique to use the smallest effective cuff appropriate for the size of the vessel or bronchus, one can make the transplantation procedure safer, faster, and more successful. Since diameters of the PV, PA, and Br are related to the body weight of the rat, we present a strategy to choosing an appropriate size using a weight-based guide. Since lung volume is also related to body weight, we recommend that this relationship should also be considered when choosing the proper volume of air for donor lung inflation during warm ischemia as well as for the proper volume of PBS to be instilled during bronchoalveolar lavage (BAL) fluid collection. We also describe methods for 4th intercostal space dissection, wound closure, and sample collection from both the native and transplanted lobes.

Here, we present optimizations to a rat lung transplantation model that serve to improve outcomes. We provide a size guide for cuffs based on body weight, a measurement strategy to ascertain the 4th intercostal space, and methods of wound closure and BAL (bronchoalveolar lavage) fluid and tissue collection.

From our experience with rat lung transplantation, we have found several areas for improvement. Information in the existing literature regarding methods ...

Employing the Forced Oscillation Technique for the Assessment of Respiratory Mechanics in Adults

There is increasing interest in the use of the forced oscillation technique (FOT) or oscillometry to characterize respiratory mechanics in healthy and diseased individuals. FOT, a complementary method to traditional pulmonary function testing, utilizes a range of oscillatory frequencies superimposed on tidal breathing to measure the functional relationship between airway pressure and flow. This passive assessment provides an estimate of respiratory system resistance (Rrs) and reactance (Xrs) that reflect airway caliber and energy storage and dissipation, respectively. Despite the recent increase in popularity and updated Technical Standards, clinical adoption has been slow which relates, in part, to the lack of standardization regarding the acquisition and reporting of FOT data. The goal of this article is to address the lack of standardization across laboratories by providing a comprehensive written protocol for FOT and an accompanying video. To illustrate that this protocol can be utilized irrespective of a particular device, three separate FOT devices have been employed in the case examples and video demonstration. This effort is intended to standardize the use and interpretation of FOT, provide practical suggestions, as well as highlight future questions that need to be addressed.

As the use of forced oscillation technique (FOT) is increasingly utilized to characterize respiratory mechanics, there is a need to standardize methods with respect to nascent technical guidelines and various manufacturer's recommendations. A detailed protocol is provided including FOT assessment and interpretation for two cases to facilitate the standardization of methods.

There is increasing interest in the use of the forced oscillation technique (FOT) or oscillometry to characterize respiratory mechanics in healthy and ...

Standardized Tuina Protocol for Rat DRG Compression Model

Analgesic Effect of Tuina on Rat Models with Compression of the Dorsal Root Ganglion Pain

Neuropathic pain is a prevalent condition that affects 6.9%-10% of the population and results from nerve damage due to various etiologies, such as lumbar disc herniation, spinal canal stenosis, and intervertebral foramen stenosis. Although Tuina, a traditional Chinese manual therapy, has shown analgesic effects in clinical practice for the treatment of neuropathic pain, its underlying neurobiological mechanisms remain unclear. Animal models are essential for elucidating the basic principles of Tuina. In this study, we propose a standardized Tuina protocol for rats with compression of the dorsal root ganglion (DRG), which involves inducing DRG compression by inserting a stainless steel rod into the intervertebral foramen, performing Tuina manipulation with specific parameters of location, intensity, and frequency in a controlled environment, and assessing the behavioral and histopathological outcomes of Tuina treatment. This article also discusses the potential clinical implications and limitations of the study and suggests directions for future research on Tuina.

Author Spotlight: Analgesic Effect of Tuina on Rat Models with Compression of the Dorsal Root Ganglion Pain  

This article presents a manipulation for treating chronic compression of the dorsal root ganglion in rats using Tuina therapy, along with a method for evaluating its effectiveness based on pain behavior and histopathological results.

Neuropathic pain is a prevalent condition that affects 6.9%-10% of the population and results from nerve damage due to various etiologies, such as lumbar ...

In Vivo Heart Transplantation to Study Endothelial-to-Mesenchymal Transition

A Neonatal Heterotopic Rat Heart Transplantation Model for the Study of Endothelial-to-Mesenchymal Transition

Endocardial fibroelastosis (EFE), defined by subendocardial tissue accumulation, has major impacts on the development of the left ventricle (LV) and precludes patients with congenital critical aortic stenosis and hypoplastic left heart syndrome (HLHS) from curative anatomical biventricular surgical repair. Surgical resection is currently the only available therapeutic option, but EFE often recurs, sometimes with an even more infiltrative growth pattern into the adjacent myocardium.
To better understand the underlying mechanisms of EFE and to explore therapeutic strategies, an animal model suitable for preclinical testing was developed. The animal model takes into consideration that EFE is a disease of the immature heart and is associated with flow disturbances, as supported by clinical observations. Thus, the heterotopic heart transplantation of neonatal rat donor hearts is the basis for this model.
A neonatal rat heart is transplanted into an adolescent rat&#39;s abdomen and connected to the recipient&#39;s infrarenal aorta and inferior vena cava. While perfusion of the coronary arteries preserves the viability of the donor heart, flow stagnation within the LV induces EFE growth in the very immature heart. The underlying mechanism of EFE formation is the transition of endocardial endothelial cells to mesenchymal cells (EndMT), which is a well-described mechanism of early embryonic development of the valves and septa but also the leading cause of fibrosis in heart failure. EFE formation can be macroscopically observed within days after transplantation. Transabdominal echocardiography is used to monitor the graft viability, contractility, and the patency of the anastomoses. Following euthanasia, the EFE tissue is harvested, and it shows the same histopathological characteristics as human EFE tissue from HLHS patients.
This in vivo model allows for studying the mechanisms of EFE development in the heart and testing treatment options to prevent this pathological tissue formation and provides the opportunity for a more generalized examination of EndMT-induced fibrosis.

Author Spotlight: A Neonatal Heterotopic Rat Heart Transplantation Model for the Study of Endothelial-to-Mesenchymal Transition  

This work presents an animal model of endothelial-to-mesenchymal transition-induced fibrosis, as seen in congenital cardiac defects such as critical aortic stenosis or hypoplastic left heart syndrome, which allows for detailed histological tissue evaluation, the identification of regulatory signaling pathways, and the testing of treatment options.

Endocardial fibroelastosis (EFE), defined by subendocardial tissue accumulation, has major impacts on the development of the left ventricle (LV) and ...