Name: inducement and evaluation of a murine model of experimental myopia
Uploaded: 2019-01-22T14:30:00
Description: Watch this Scientific Journal Video about Inducement and Evaluation of a Murine Model of Experimental Myopia at JoVE.com

We thank M.T. Pardue for advice on the SD&#173;OCT, F. Schaeffel for advice on measurements of refraction and corneal curvature, Mr. Sanshouo for recreating the three-dimensional frame data, M. Miyauchi; K. Tsubota; Y. Tanaka; S. Kondo; C. Shoda; M. Ibuki; Y. Miwa; Y. Hagiwara; A. Ishida; Y. Tomita; Y. Katada; E. Yotsukura; K. Takahashi; and Y. Wang for critical discussions. This work was supported by Grants&#173; in&#173;Aid for Scientific Research (KAKENHI, number 15K10881) from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) to TK. This work is also supported by the grant for myopia research from Tsubota Laboratory, Inc. (Tokyo Japan).

All procedures were approved by the Ethics Committee on Animal Research of the Keio University School of Medicine adhered to the ARVO Statement for the Use of Animals in Ophthalmic and Vision Research, the Institutional Guidelines on Animal Experimentation at Keio University, and the Animal Research: Reporting of In Vivo Experiments (ARRIVE) guidelines for the use of animals in research.
1. Assembling the Eyeglasses for Mice
<ol>
	<li>Prepare parts needed for assembling the eyeglasses (<stro...

<ol>
	<li>Dolgin, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+myopia+boom.">The myopia boom.</a> Nature. 519 (7543), 276-278 (2015).</li><li>Ohno-Matsui, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pathologic+Myopia.">Pathologic Myopia.</a> Asia-Pacific Journal of Ophthalmology (Philadelphia, Pa). 5 (6), 415-423 (2016).</li><li>Morgan, I. G., Ashby, R. S., Nickla, D. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Form+deprivation+and+lens-induced+myopia:+are+they+different.">Form deprivation and lens-induced myopia: are they different.</a> Ophthalmic &amp; Physiological Optics. 33 (3), 355-361 (2013).</li><li>Jiang, X., 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=A+highly+efficient+murine+model+of+experimental+myopia.">A highly efficient murine model of experimental myopia.</a> Scientific Reports. 8 (1), 2026 (2018).</li><li>Torii, H., 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=Violet+Light+Exposure+Can+Be+a+Preventive+Strategy+Against+Myopia+Progression.">Violet Light Exposure Can Be a Preventive Strategy Against Myopia Progression.</a> EBioMedicine. 15, 210-219 (2017).</li><li>Smith, E. L., 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=Effects+of+Long-Wavelength+Lighting+on+Refractive+Development+in+Infant+Rhesus+Monkeys.">Effects of Long-Wavelength Lighting on Refractive Development in Infant Rhesus Monkeys.</a> Investigative Ophthalmology &amp; Visual Science. 56 (11), 6490-6500 (2015).</li><li>Gawne, T. J., Siegwart, J. T., Ward, A. H., Norton, T. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+wavelength+composition+and+temporal+modulation+of+ambient+lighting+strongly+affect+refractive+development+in+young+tree+shrews.">The wavelength composition and temporal modulation of ambient lighting strongly affect refractive development in young tree shrews.</a> Experimental Eye Research. 155, 75-84 (2017).</li><li>Wu, 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=Early+quantitative+profiling+of+differential+retinal+protein+expression+in+lens-induced+myopia+in+guinea+pig+using+fluorescence+difference+two-dimensional+gel+electrophoresis.">Early quantitative profiling of differential retinal protein expression in lens-induced myopia in guinea pig using fluorescence difference two-dimensional gel electrophoresis.</a> Molecular Medicine Reports. , (2018).</li><li>Schaeffel, F., Burkhardt, E., Howland, H. C., Williams, R. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measurement+of+refractive+state+and+deprivation+myopia+in+two+strains+of+mice.">Measurement of refractive state and deprivation myopia in two strains of mice.</a> Optometry and Vision Science. 81 (2), 99-110 (2004).</li><li>Tkatchenko, T. V., Shen, Y., Tkatchenko, A. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mouse+experimental+myopia+has+features+of+primate+myopia.">Mouse experimental myopia has features of primate myopia.</a> Investigative Ophthalmology &amp; Visual Science. 51 (3), 1297-1303 (2010).</li><li>Faulkner, A. E., Kim, M. K., Iuvone, P. M., Pardue, M. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Head-mounted+goggles+for+murine+form+deprivation+myopia.">Head-mounted goggles for murine form deprivation myopia.</a> Journal of Neuroscience Methods. 161 (1), 96-100 (2007).</li><li>Gu, 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=A+Head-Mounted+Spectacle+Frame+for+the+Study+of+Mouse+Lens-Induced+Myopia.">A Head-Mounted Spectacle Frame for the Study of Mouse Lens-Induced Myopia.</a> Journal of Ophthalmology. 2016, 8497278 (2016).</li><li>Siegwart, J. T., Norton, T. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Goggles+for+controlling+the+visual+environment+of+small+animals.">Goggles for controlling the visual environment of small animals.</a> Laboratory Animal Science. 44 (3), 292-294 (1994).</li><li>Tkatchenko, T. V., Tkatchenko, A. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ketamine-xylazine+anesthesia+causes+hyperopic+refractive+shift+in+mice.">Ketamine-xylazine anesthesia causes hyperopic refractive shift in mice.</a> Journal of Neuroscience Methods. 193 (1), 67-71 (2010).</li><li>Chou, T. H., 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=Postnatal+elongation+of+eye+size+in+DBA/2J+mice+compared+with+C57BL/6J+mice:+in+vivo+analysis+with+whole-eye+OCT.">Postnatal elongation of eye size in DBA/2J mice compared with C57BL/6J mice: in vivo analysis with whole-eye OCT.</a> Investigative Ophthalmology &amp; Visual Science. 52 (6), 3604-3612 (2011).</li><li>Park, H., 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=Assessment+of+axial+length+measurements+in+mouse+eyes.">Assessment of axial length measurements in mouse eyes.</a> Optometry and Vision Science. 89 (3), 296-303 (2012).</li></ol>

To make sure the eyeglasses to be fixed stably on the mouse head, several steps in this protocol need to be paid great attention. The periosteum must be removed completely before using the dental adhesive system. The blood on the skull also need to be cleaned up with care. While a little fine tuning is acceptable right after the application of the adhesive, do not move the stick frequently before the adhesive system dry up. Follow the instruction of the adhesive system carefully, especially the ratio of each component of...

The prevalence of myopia has increased dramatically recently, while the mechanism of its onset and progression are still largely unknow1. The most characteristic phenotype of myopia is the elongation of axial length (AL), which increases risk for retinal complications or even blindness2. To better understand the pathogenesis of myopia and develop effective treatments, robust myopic animal models and stable phenotype evaluation are necessary.
Briefly, two methods exist for inducing myopic states in animals: form-deprivation myopia (FDM) and lens-induced myopia (LIM)3. The former places diffusers in front of the eye or sutures the eyelid to obscure the image, which influences the normal development of the eyeball, resulting in a myopia phenotype. The latter places minus lenses in front of the eye to move the focal point behind the retina. The retina detects the shift of the focus and elongates the eyeball to realign the retina and focal point. For FDM, after the eyelid is closed or the diffuser has been fixed in front of the eye, almost no further maintenance is needed. For LIM, the lens needs to be taken off for cleaning in order to keep it transparent. Thus, FDM is relatively easy to be induced technically. However, the mechanisms of FDM and LIM are different, and which method mimics the myopia in human better is still under debate3. One of the strengths of LIM is the stronger phenotype compared with FDM, at least in the case of mice4.
Animals that have been used for inducing myopia include chicks5, monkeys6, tree shrews7, guinea pigs8, and mice4. Considering the possibility of genetic manipulation, abundant available antibodies, and low cost for breeding, mice could have been the first choice as the animal model of myopia. However, compared with other larger animals, fixing lenses or diffusers in front of the mouse eye is relatively difficult especially for young mice such as right after weaning. For the experiments that need topical drug administration or multiple interim eye measurements, it is also necessary for the frame to be removable. Another challenge is the small morphological change of mouse eyeball, which needs sophisticated technics and devices to evaluate. To date, different inducing and measuring protocols used in different research teams make it hard to compare and repeat the results across laboratories. A standard protocol with details is needed.
Previous works described multiple methods to fix lenses or diffusers in front of the mouse eye, such as gluing9, stitching10 and head-mounted goggle frame11,12. We combined the exist head-mounted goggle technics11,12,13 with our newly designed frame to develop an ameliorated protocol for inducing robust and efficient experimental myopia in mice. The protocol can be applied to young mice soon after weaning at postnatal day 21 (p21). We also optimized the processes for stable and precise evaluation of phenotypes including the refraction and AL. We hope this standardized protocol can help to make myopic mice a more easily accessible model for myopia research.

<table>
	<tbody>
		<tr>
			<td>screw</td>
			<td>NBK</td>
			<td>SNZS-M1.4-10</td>
			<td></td>
		</tr>
		<tr>
			<td>washer</td>
			<td>MonotaRO</td>
			<td>42166397</td>
			<td></td>
		</tr>
		<tr>
			<td>nut</td>
			<td>MonotaRO</td>
			<td>42214243</td>
			<td></td>
		</tr>
		<tr>
			<td>stick</td>
			<td>DMM Make</td>
			<td>none</td>
			<td>designed by authers and output by the 3D printer rented from DMM Make.</td>
		</tr>
		<tr>
			<td>frame</td>
			<td>DMM Make</td>
			<td>none</td>
			<td>designed by authers and output by the 3D printer rented from DMM Make.</td>
		</tr>
		<tr>
			<td>lenses</td>
			<td>RAINBOW CONTACT LENS</td>
			<td>none</td>
			<td>customized for mice use by the company</td>
		</tr>
		<tr>
			<td>cyanoacrylate glue</td>
			<td>OK MODEL</td>
			<td>MP 20g</td>
			<td></td>
		</tr>
		<tr>
			<td>dental adhesive resin cement</td>
			<td>SUN MEDICAL</td>
			<td>super bond</td>
			<td>contains the etching liquid used for removing the periosteum of the mouse skull</td>
		</tr>
		<tr>
			<td>infrared photorefractor</td>
			<td>Steinbeis Transfer Center</td>
			<td>none</td>
			<td>designed and offered by Dr. Frank Schaeffel from university of T&#252;bingen</td>
		</tr>
		<tr>
			<td>Spectral domain OCT</td>
			<td>Leica</td>
			<td>R4310</td>
			<td></td>
		</tr>
		<tr>
			<td>Tropicamide, Penylephrine Hydrochloride solution</td>
			<td>Santen</td>
			<td>Mydrin-P</td>
			<td></td>
		</tr>
		<tr>
			<td>midazolam</td>
			<td>Sandoz K.K.</td>
			<td>SANDOZ</td>
			<td>components for the anesthetic</td>
		</tr>
		<tr>
			<td>medetomidine&#160;</td>
			<td>Orion Corporation</td>
			<td>Domitor</td>
			<td>components for the anesthetic</td>
		</tr>
		<tr>
			<td>butorphanol tartrate&#160;</td>
			<td>Meiji Seika Pharma</td>
			<td>Vetorphale</td>
			<td>components for the anesthetic</td>
		</tr>
		<tr>
			<td>0.1 % purified sodium hyaluronate</td>
			<td>Santen</td>
			<td>Hyalein</td>
			<td></td>
		</tr>
		<tr>
			<td>atipamezole hydrochloride</td>
			<td>Zenoaq</td>
			<td>antisedan</td>
			<td></td>
		</tr>
	</tbody>
</table>

inducement and evaluation of a murine model of experimental myopia

Murine model of myopia can be a powerful tool for myopia research because of the comparatively easy genetic manipulation. One way to induce myopia in animals is to put clear minus lenses in front of eyes for weeks (lens-induced myopia, LIM). However, extant protocols for inducement and evaluation vary from laboratory to laboratory. Here, we described a highly practical and reproducible method to induce LIM in mice using newly designed eyeglasses. The method fixes the lens stably in front of the mouse eye while allows the lens to be taken off for cleaning or topical drug administration. The phenotype is robust and efficient, and the variance is small. The method described here can be applied to mice right after weaning which extends the possible duration for experiments. We also gave technical advises for achieving reproducible results in refraction and axial length measurements. We hope the step-by-step protocol described here and the detailed article can help researchers perform myopia experiments with myopia more smoothly and make the data comparable across laboratories.

At first, check if all the necessary parts are prepared (Figure 1a). An example of a piece of assembled eyeglasses is shown in Figure 1b. Except for the main body of the frames and the nut, all other parts are disposable for each mouse. A set of completed eyeglasses is shown in Figure 1c. Change the angle between the two frames to fit the mouse with different ages.
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Watch this Scientific Journal Video about Inducement and Evaluation of a Murine Model of Experimental Myopia at JoVE.com

Inducement and Evaluation of a Murine Model of Experimental Myopia

In this protocol, we describe the full process of experimental myopia inducement in mice using newly designed eyeglasses and the technic needed for achieving stable and reproducible results in ocular parameter measurements.

Murine model of myopia can be a powerful tool for myopia research because of the comparatively easy genetic manipulation. One way to induce myopia in ...

This method can help to answer key questions about inducing and evaluating lens-induced myopia in mice. Such as how to stabilize lenses. The main number one stage of this technique is that all of the steps have been optimized and standardized allowing the acquisition of precise, reproducible and comparable results across labs.Generally, people new to this method is struggle since it is very hard to glue the eyeglasses onto the mouse heads stably without any practice. For each mouse, prepare the following. One head-mounted nylon stick.One higher and one lower titanium frame. Two lenses with the appropriate powers according to the purpose of the experiment. One 10mm length M1.4 size screw.One nut for the M1.4 size screw. 1 plain washer for the 0.3 millimeter thick M1.4 size screw. And two artificial fingernail tips.To assemble the right eyeglasses frame, arrange a fingernail tip to face the outside direction to achieve the best protective effect. And, adjust the angle between the fingernail tip and frame to about 130 degrees to avoid masking the mouse-vision field. Using cyanoacrylate adhesive, adhere the artificial fingernail tip to the frame and allow the adhesive 12 hours to completely dry.Use nail clippers to trim the fully adhered fingernail tip to about a one by one centimeter shape and place the lens onto the frame. Inject the cyanoacrylate adhesive from the edge of the lens and let the adhesive spread by surface tension. When the adhesive is dry, tighten the screw into the nylon stick together with the washer from the flat side of the stick.Then prepare the left frame in the same manner with the fingertip angled in the opposite direction of the right frame tip. For baseline measurement of the refraction in the axial length, apply one drop of mydriatic agent, containing five milligrams per milliliter tropicamide and five milligrams per milliliter phenylephrine hydrochloride on each side of the eyeball to dilate the pupil. Wait for at least five minutes before general anesthesia and adjust the direction of one of the eyes within the viewfinder of an infrared photo refractor to position the first Purkinje image in the center of the pupil and measure the refraction along the optical axis.After measuring the other eye in the same manner, place the mouse in the spectral domain optical coherence tomography system and define the axial length as the distance from the corneal vortex to the brightest boundary near the optical nerve. To fix the previously prepared goggle frame onto the mouse, first apply one drop of 0.1%purified sodium hyaluronate eye drop to each eye and place the chin of the anesthetized mouse onto a sloped surface so the upfront plane of the cranium is horizontal. Use a cotton swab soaked with 70%ethanol to sterilize the hair and scalp, between the ears and eyes, and make a 0.8 square cm incision in the skin, between the ears and the eyes, to expose the skull.Use dental etching liquid in a cotton swab to remove the periosteum and use a pair of frames without lenses to help fix the stick onto the right position, carefully adjusting the position of the frames to make sure that both eyes are in the middle of the empty frames. Use a self-care dental adhesive system to attach the stick onto the mouse head and wait about five minutes before carefully removing the frame and the nut without changing the position of the stick. Then inject 0.75 milligrams per kilogram of atipamazole hydrochloride intraperitoneally to help the mouse to recover from the anesthesia more quickly and place the mouse into an individual cage until fully recovered.24 hours after the surgery, grasp the stick and place the frames with lenses onto the animal to initiate the myopia induction. Then place a net between the mouse and the cage bottom to filter the food scraps and monitor the body weight and gross behavior daily, comparing the myopic mice with same aged, untouched mice during the entire experimental process. Remove the frame and clean the lenses and the fingernail tip with cotton swabs at least two times a week to maintain the transparency of the lenses.Here, a set of completed eye glasses is shown. The angle between the two frames can be adjusted to fit mice of different ages. After placing the eyeglasses onto the frame as demonstrated, the two pieces of eyeglasses should be fairly symmetrical.For this refraction measurement in a mouse eye induced by a negative 30 dioptre lens for three weeks, starting from post-natal day 21, the gaze was controlled close to zero degrees in both the x and y axis, indicating that the mouse was seeing right in front of the camera. This whole eye image, taken by a spectral domain optical coherence tomography system, tuned for mice, allows each part of the eye to be defined. In this representative experiment, negative 30 dioptre lenses induced a strong myopic shift in both the refraction and axial length measurements, compared to the zero dioptre lenses.The change in refraction peaked in the first week and stayed flat for the following two weeks, while the difference between the change of myopic eye and control eye axial lengths was significant from the first week and became larger and larger in the following two weeks. While attempting the procedure, it's important to remember to closely follow the instruction for measuring the refraction and axial lens, to allow the result to be comparable across the experimental labs. After its development the technique pave the way for researchers in the field of myopia to explore pathogenic mechanism in, not only ordinary mice, but also genetically modified mice.

inducement-and-evaluation-of-a-murine-model-of-experimental-myopia

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Neuroscience

Experimental Demyelination and Remyelination of Murine Spinal Cord by Focal Injection of Lysolecithin

Multiple sclerosis is an inflammatory demyelinating disease of the central nervous system characterized by plaque formation containing lost oligodendrocytes, myelin, axons, and neurons. Remyelination is an endogenous repair mechanism whereby new myelin is produced subsequent to proliferation, recruitment, and differentiation of oligodendrocyte precursor cells into myelin-forming oligodendrocytes, and is necessary to protect axons from further damage. Currently, all therapeutics for the treatment of multiple sclerosis target the aberrant immune component of the disease, which reduce inflammatory relapses but do not prevent progression to irreversible neurological decline. It is therefore imperative that remyelination-promoting strategies be developed which may delay disease progression and perhaps reverse neurological symptoms. Several animal models of demyelination exist, including experimental autoimmune encephalomyelitis and curprizone; however, there are limitations in their use for studying remyelination. A more robust approach is the focal injection of toxins into the central nervous system, including the detergent lysolecithin into the spinal cord white matter of rodents. In this protocol, we demonstrate that the surgical procedure involved in injecting lysolecithin into the ventral white matter of mice is fast, cost-effective, and requires no additional materials than those commercially available. This procedure is important not only for studying the normal events involved in the remyelination process, but also as a pre-clinical tool for screening candidate remyelination-promoting therapeutics.

Demyelinating diseases can be modeled in animals by focal application of lysolecithin into the CNS. A single injection of lysolecithin into mouse spinal cord produces a lesion that spontaneously repairs over time. The goal is to study factors involved in de- and remyelination, and to test agents for enhancing repair.

Multiple sclerosis is an inflammatory demyelinating disease of the central nervous system characterized by plaque formation containing lost ...

Visual Evoked Potential Recording in a Rat Model of Experimental Optic Nerve Demyelination

The visual evoked potential (VEP) recording is widely used in clinical practice to assess the severity of optic neuritis in its acute phase, and to monitor the disease course in the follow-up period. Changes in the VEP parameters closely correlate with pathological damage in the optic nerve. This protocol provides a detailed description about the rodent model of optic nerve microinjection, in which a partial demyelination lesion is produced in the optic nerve. VEP recording techniques are also discussed. Using skull implanted electrodes, we are able to acquire reproducible intra-session and between-session VEP traces. VEPs can be recorded on individual animals over a period of time to assess the functional changes in the optic nerve longitudinally. The optic nerve demyelination model, in conjunction with the VEP recording protocol, provides a tool to investigate the disease processes associated with demyelination and remyelination, and can potentially be employed to evaluate the effects of new remyelinating drugs or neuroprotective therapies.

Focal demyelination is induced in the optic nerve using lysolecithin microinjection. Visual evoked potentials are recorded via skull electrodes implanted over the visual cortex to examine the signal conduction along the visual pathway in vivo. This protocol details the surgical procedures underlying electrode implantation and optic nerve microinjection.

The visual evoked potential (VEP) recording is widely used in clinical practice to assess the severity of optic neuritis in its acute phase, and to ...

Evaluation of Bioenergetic Function in Cerebral Vascular Endothelial Cells

The integrity of the blood-brain-barrier (BBB) is critical to prevent brain injury. Cerebral vascular endothelial (CVE) cells are one of the cell types that comprise the BBB; these cells have a very high-energy demand, which requires optimal mitochondrial function. In the case of disease or injury, the mitochondrial function in these cells can be altered, resulting in disease or&#160;the opening of the BBB. In this manuscript, we introduce a method to measure mitochondrial function in CVE cells by using whole, intact cells and a bioanalyzer. A mito-stress assay is used to challenge the cells that have been perturbed, either physically or chemically, and evaluate their bioenergetic function. Additionally, this method also provides a useful way to screen new therapeutics that have direct effects on mitochondrial function. We have optimized the cell density necessary to yield oxygen consumption rates that allow for the calculation of a variety of mitochondrial parameters, including ATP production, maximal respiration, and spare capacity. We also show the sensitivity of the assay by demonstrating that the introduction of the&#160;microRNA, miR-34a, leads to a pronounced and detectable decrease in mitochondrial activity. While the data shown in this paper is optimized for the bEnd.3 cell line, we have also optimized the protocol for primary CVE cells, further suggesting the utility in preclinical and clinical models.

Endothelial cell mitochondria are critical to maintain blood-brain-barrier integrity. We introduce a protocol to measure bioenergetic function in cerebral vascular endothelial cells.

The integrity of the blood-brain-barrier (BBB) is critical to prevent brain injury. Cerebral vascular endothelial (CVE) cells are one of the cell types ...

Biodegradable Magnesium Stent Treatment of Saccular Aneurysms in a Rat Model - Introduction of the Surgical Technique

The steady progess in the armamentarium of techniques available for endovascular treatment of intracranial aneurysms requires affordable and reproducable experimental animal models to test novel embolization materials such as stents and flow diverters. The aim of the present project was to design a safe, fast, and standardized surgical technique for stent assisted embolization of saccular aneurysms in a rat animal model.
Saccular aneurysms were created from an arterial graft from the descending aorta.The aneurysms were microsurgically transplanted through end-to-side anastomosis to the infrarenal abdominal aorta of a syngenic male Wistar rat weighing &#62;500 g. Following aneurysm anastomosis, aneurysm embolization was performed using balloon expandable magnesium stents (2.5 mm x 6 mm). The stent system was retrograde introduced from the lower abdominal aorta using a modified Seldinger technique.
Following a pilot series of 6 animals, a total of 67 rats were operated according to established standard operating procedures. Mean surgery time, mean anastomosis time, and mean suturing time of the artery puncture site were 167 &#177; 22 min, 26 &#177; 6 min and 11 &#177; 5 min, respectively. The mortality rate was 6% (n=4). The morbidity rate was 7.5% (n=5), and in-stent thrombosis was found in 4 cases (n=2 early, n=2 late in stent thrombosis).
The results demonstrate the feasibility of standardized stent occlusion of saccular sidewall aneurysms in rats - with low rates of morbidity and mortality. This stent embolization procedure combines the opportunity to study novel concepts of stent or flow diverter based devices as well as the molecular aspects of healing.

Reproducable experimental animal models are needed for the testing of novel embolization materials, which have been designed to treat endovascular occlusion of intracranial aneurysms (IA). The present study aims to develop a safe and standardized surgical technique for stent assisted embolization of saccular aneurysms in a rat animal model.

The steady progess in the armamentarium of techniques available for endovascular treatment of intracranial aneurysms requires affordable and reproducable ...

A Volumetric Method for Quantification of Cerebral Vasospasm in a Murine Model of Subarachnoid Hemorrhage

Subarachnoid hemorrhage (SAH) is a subtype of hemorrhagic stroke. Cerebral vasospasm that occurs in the aftermath of the bleeding is an important factor determining patient outcome and is therefore frequently taken as a study endpoint. However, in small animal studies on SAH, quantification of cerebral vasospasm is a major challenge. Here, an ex vivo method is presented that allows quantification of volumes of entire vessel segments, which can be used as an objective measure to quantify cerebral vasospasm. In a first step, endovascular casting of the cerebral vasculature is performed using a radiopaque casting agent. Then, cross-sectional imaging data are acquired by micro computed tomography. The final step involves 3-dimensional reconstruction of the virtual vascular tree, followed by an algorithm to calculate center lines and volumes of the selected vessel segments. The method resulted in a highly accurate virtual reconstruction of the cerebrovascular tree shown by a diameter-based comparison of anatomical samples with their virtual reconstructions. Compared with vessel diameters alone, the vessel volumes highlight the differences between vasospastic and non-vasospastic vessels shown in a series of SAH and sham-operated mice.

The goal of this article is to present a method that allows a 3-dimensional reconstruction of the cerebrovascular tree in mice after micro computed tomography and determination of volumes of entire vessel segments that can be used to quantify cerebral vasospasm in murine models of subarachnoid hemorrhage.

Subarachnoid hemorrhage (SAH) is a subtype of hemorrhagic stroke. Cerebral vasospasm that occurs in the aftermath of the bleeding is an important factor ...

Functional Evaluation of Olfactory Pathways in Living Xenopus Tadpoles

Xenopus tadpoles offer a unique platform to investigate the function of the nervous system. They provide multiple experimental advantages, such as accessibility to numerous imaging approaches, electrophysiological techniques and behavioral assays. The Xenopus tadpole olfactory system is particularly well suited to investigate the function of synapses established during normal development or reformed after injury. Here, we describe methodologies to evaluate the processing of olfactory information in living Xenopus larvae. We outline a combination of in vivo measurements of presynaptic calcium responses in glomeruli of the olfactory bulb with olfactory-guided behavior assays. Methods can be combined with the transection of olfactory nerves to study the rewiring of synaptic connectivity. Experiments are presented using both wild-type and genetically modified animals expressing GFP reporters in central nervous system cells. Application of the approaches described to genetically modified tadpoles can be useful for unraveling the molecular bases that define vertebrate behavior.

Functional Evaluation of Olfactory Pathways in Living Xenopus Tadpoles

Xenopus tadpoles offer a unique platform to investigate the function of the nervous system in vivo. We describe methodologies to evaluate the processing of olfactory information in living Xenopus larvae in normal rearing conditions or after injury.

Xenopus tadpoles offer a unique platform to investigate the function of the nervous system. They provide multiple experimental advantages, such as ...

Pre-Chiasmatic, Single Injection of Autologous Blood to Induce Experimental Subarachnoid Hemorrhage in a Rat Model

Despite advances in treatment over the last decades, subarachnoid hemorrhage (SAH) continues to carry a high burden of morbidity and mortality, largely afflicting a fairly young population. Several animal models of SAH have been developed to investigate the pathophysiological mechanisms behind SAH and to test pharmacological interventions. The pre-chiasmatic, single injection model in the rat presented in this article is an experimental model of SAH with a predetermined blood volume. Briefly, the animal is anesthetized, intubated, and kept under mechanical ventilation. Temperature is regulated with a heating pad. A catheter is placed in the tail artery, enabling continuous blood pressure measurement as well as blood sampling. The atlantooccipital membrane is incised and a catheter for pressure recording is placed in the cisterna magna to enable intracerebral pressure measurement. This catheter can also be used for intrathecal therapeutic interventions. The rat is placed in a stereotaxic frame, a burr hole is drilled anteriorly to the bregma, and a catheter is inserted through the burr hole and placed just anterior to the optic chiasm. Autologous blood (0.3 mL) is withdrawn from the tail catheter and manually injected. This results in a rise of intracerebral pressure and a decrease of cerebral blood flow. The animal is kept sedated for 30 min and given subcutaneous saline and analgesics. The animal is extubated and returned to its cage. The pre-chiasmatic model has a high reproducibility rate and limited variation between animals due to the pre-determined blood volume. It mimics SAH in humans making it a relevant model for SAH research.

Subarachnoid hemorrhage continues to carry a high burden of mortality and morbidity in man. To facilitate further research into the condition and its pathophysiology, a pre-chiasmatic, single injection model is presented.

Despite advances in treatment over the last decades, subarachnoid hemorrhage (SAH) continues to carry a high burden of morbidity and mortality, largely ...

A Model for Epilepsy of Infectious Etiology using Theiler's Murine Encephalomyelitis Virus

One of the main causes of epilepsy is an infection of the central nervous system (CNS); approximately 8% of patients who survive such an infection develop epilepsy as a consequence, with rates being significantly higher in less economically developed countries. This work provides an overview of modeling epilepsy of infectious etiology and using it as a platform for novel antiseizure compound testing. A protocol of epilepsy induction by non-stereotactic intracerebral injection of Theiler's murine encephalomyelitis virus (TMEV) in C57BL/6 mice is presented, which replicates many of the early and chronic clinical symptoms of viral encephalitis and subsequent epilepsy in human patients. The clinical evaluation of mice during encephalitis to monitor seizure activity and detect the potential antiseizure effects of novel compounds is described. Furthermore, histopathological consequences of viral encephalitis and seizures such as hippocampal damage and neuroinflammation are shown, as well as long-term consequences such as spontaneous epileptic seizures. The TMEV model is one of the first translational, infection-driven, experimental platforms to allow for the investigation of the mechanisms of epilepsy development as a consequence of CNS infection. Thus, it also serves to identify potential therapeutic targets and compounds for patients at risk of developing epilepsy following a CNS infection.

A Model for Epilepsy of Infectious Etiology using Theiler&#039;s Murine Encephalomyelitis Virus

Intracerebral infection with the Theiler's murine encephalomyelitis virus (TMEV) in C57BL/6 mice replicates many of the early and chronic clinical symptoms of viral encephalitis and subsequent epilepsy in human patients. This paper describes the virus infection, symptoms, and histopathology of the TMEV model.

One of the main causes of epilepsy is an infection of the central nervous system (CNS); approximately 8% of patients who survive such an infection develop ...

A Mouse Model to Study Brain Physiology During Cardiac Arrest

Mouse Cardiac Arrest Model for Brain Imaging and Brain Physiology Monitoring During Ischemia and Resuscitation

Most cardiac arrest (CA) survivors experience varying degrees of neurologic deficits. To understand the mechanisms that underpin CA-induced brain injury and, subsequently, develop effective treatments, experimental CA research is essential. To this end, a few mouse CA models have been established. In most of these models, the mice are placed in the supine position in order to perform chest compression for cardiopulmonary resuscitation (CPR). However, this resuscitation procedure makes the real-time imaging/monitoring of brain physiology during CA and resuscitation challenging. To obtain such critical knowledge, the present protocol presents a mouse asphyxia CA model that does not require the chest compression CPR step. This model allows for the study of dynamic changes in blood flow, vascular structure, electrical potentials, and brain tissue oxygen from the pre-CA baseline to early post-CA reperfusion. Importantly, this model applies to aged mice. Thus, this mouse CA model is expected to be a critical tool for deciphering the impact of CA on brain physiology.

Author Spotlight: A Unique Mouse Model of Asphyxia-Induced Cardiac Arrest 

This protocol demonstrates a unique mouse model of asphyxia cardiac arrest that does not require chest compression for resuscitation. This model is useful for monitoring and imaging the dynamics of brain physiology during cardiac arrest and resuscitation.

Most cardiac arrest (CA) survivors experience varying degrees of neurologic deficits. To understand the mechanisms that underpin CA-induced brain injury ...

A Model of Transient Cerebral Ischemia by Occlusion of Middle Cerebral Artery

Transient Middle Cerebral Artery Occlusion Model of Stroke

Stroke stands as a major cause of death or chronic disability globally. Nevertheless, existing optimal treatments are limited to reperfusion therapies during the acute phase of ischemic stroke. To gain insights into stroke physiopathology and develop innovative therapeutic approaches, in vivo rodent models of stroke play a fundamental role. The availability of genetically modified animals has particularly propelled the use of mice as experimental stroke models.
In stroke patients, occlusion of the middle cerebral artery (MCA) is a common occurrence. Consequently, the most prevalent experimental model involves intraluminal occlusion of the MCA, a minimally invasive technique that doesn't require craniectomy. This procedure involves inserting a monofilament through the external carotid artery (ECA) and advancing it through the internal carotid artery (ICA) until it reaches the branching point of the MCA. After a 45 min arterial occlusion, the monofilament is removed to allow reperfusion. Throughout the process, cerebral blood flow is monitored to confirm the reduction during occlusion and subsequent recovery upon reperfusion. Neurological and tissue outcomes are evaluated using behavioral tests and magnetic resonance imaging (MRI) studies.

Author Spotlight: Assessing Ischemic Stroke Damage Through Middle Cerebral Artery Occlusion Model 

This protocol describes the model of transient focal cerebral ischemia in mice through intraluminal occlusion of the middle cerebral artery. Additionally, examples of outcome assessment are shown using magnetic resonance imaging and behavioral tests.

Stroke stands as a major cause of death or chronic disability globally. Nevertheless, existing optimal treatments are limited to reperfusion therapies ...