Name: circumscribed capsular infarct modeling using a photothrombotic technique
Uploaded: 2016-06-02T13:00:00
Description: Watch this Scientific Journal Video about Circumscribed Capsular Infarct Modeling Using a Photothrombotic Technique at JoVE.com

This work was supported by a grant from the Institute of Medical System Engineering (iMSE) &#38; GIST-Caltech Collaborative Fund (K04592) from GIST and by the Basic Science Research Program through NRF of Korea funded by the Ministry of Science, ICT and future Planning (NRF-2013R1A2A2A01067890).

All procedures were conducted according to the institutional guidelines of Gwangju Institute of Science and Technology (GIST), and all procedures were approved by the Institutional Animal Care and Use Committee at GIST.
1. Pre-lesioning Steps
<ol>
	<li>Identification of the Forelimb Area in the Internal Capsule using AAV-GFP
	<ol>
		<li>House and handle Sprague Dawley rats (~400 g, 11 - 13 weeks) in compliance with institutional and national guidelines.</li>
		<li>Sterilize all surgical tools an...

<ol>
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J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+animal+model+of+capsular+infarct:+endothelin-1+injections+in+the+rat.">An animal model of capsular infarct: endothelin-1 injections in the rat.</a> Behav Brain Res. 169 (2), 206-211 (2006).</li><li>He, Z., 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=Definition+of+the+anterior+choroidal+artery+territory+in+rats+using+intraluminal+occluding+technique.">Definition of the anterior choroidal artery territory in rats using intraluminal occluding technique.</a> J Neurol Sci. 182 (1), 16-28 (2000).</li><li>Tanaka, 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=Experimental+model+of+lacunar+infarction+in+the+gyrencephalic+brain+of+the+miniature+pig:+neurological+assessment+and+histological,+immunohistochemical,+and+physiological+evaluation+of+dynamic+corticospinal+tract+deformation.">Experimental model of lacunar infarction in the gyrencephalic brain of the miniature pig: neurological assessment and histological, immunohistochemical, and physiological evaluation of dynamic corticospinal tract deformation.</a> Stroke. 39 (1), 205-212 (2008).</li><li>Shibata, M., Ohtani, R., Ihara, M., Tomimoto, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=White+matter+lesions+and+glial+activation+in+a+novel+mouse+model+of+chronic+cerebral+hypoperfusion.">White matter lesions and glial activation in a novel mouse model of chronic cerebral hypoperfusion.</a> Stroke. 35 (11), 2598-2603 (2004).</li><li>Watson, B. D., Dietrich, W. D., Busto, R., Wachtel, M. S., Ginsberg, M. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Induction+of+reproducible+brain+infarction+by+photochemically+initiated+thrombosis.">Induction of reproducible brain infarction by photochemically initiated thrombosis.</a> Ann Neurol. 17 (5), 497-504 (1985).</li><li>Kuroiwa, T., 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=Development+of+a+rat+model+of+photothrombotic+ischemia+and+infarction+within+the+caudoputamen.">Development of a rat model of photothrombotic ischemia and infarction within the caudoputamen.</a> Stroke. 40 (1), 248-253 (2009).</li><li>Bashkatov, A. N., Genina, E. A., Tuchin, V. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Handbook of biomedical optics. 83, (2011).</li><li>Yizhar, O., Fenno, L. E., Davidson, T. J., Mogri, M., Deisseroth, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optogenetics+in+neural+systems.">Optogenetics in neural systems.</a> Neuron. 71 (1), 9-34 (2011).</li><li>Whishaw, I. Q., Whishaw, P., Gorny, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+structure+of+skilled+forelimb+reaching+in+the+rat:+a+movement+rating+scale.">The structure of skilled forelimb reaching in the rat: a movement rating scale.</a> J Vis Exp. (18), e816 (2008).</li><li>Jang, S. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+review+of+corticospinal+tract+location+at+corona+radiata+and+posterior+limb+of+the+internal+capsule+in+human+brain.">A review of corticospinal tract location at corona radiata and posterior limb of the internal capsule in human brain.</a> NeuroRehabilitation. 24 (3), 279-283 (2009).</li><li>Kim, D., 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=Longitudinal+changes+in+resting-state+brain+activity+in+a+capsular+infarct+model.">Longitudinal changes in resting-state brain activity in a capsular infarct model.</a> J Cereb Blood Flow Metab. 35 (1), 11-119 (2014).</li><li>Blasi, F., Whalen, M. J., Ayata, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lasting+pure-motor+deficits+after+focal+posterior+internal+capsule+white-matter+infarcts+in+rats.">Lasting pure-motor deficits after focal posterior internal capsule white-matter infarcts in rats.</a> J Cereb Blood Flow Metab. 35 (6), 977-984 (2015).</li><li>Metz, G. A., Antonow-Schlorke, I., Witte, O. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Motor+improvements+after+focal+cortical+ischemia+in+adult+rats+are+mediated+by+compensatory+mechanisms.">Motor improvements after focal cortical ischemia in adult rats are mediated by compensatory mechanisms.</a> Behavioural brain research. 162 (1), 71-82 (2005).</li></ol>

The capsular infarct model presented here demonstrates a targeted lesion with marked and persistent motor impairment in forelimb function. Previous models of subcortical capsular stroke have demonstrated an insufficient degree of motor impairment and a rapid recovery process6,8,9 . In this sense, this model resembles the clinical capsular infarct cases which exhibit long-term functional impairment.
The most critical steps in the development of a circumscribed capsular infarct model ...

Until recently, the &#34;gray matter stroke (GMS) models&#34; have been exclusively used to understand the pathophysiology of stroke and to guide the development of new treatments. However, there has been an increasing prevalence of stroke that affects subcortical white matter in elderly individuals, which constitutes 15 - 25% of all strokes1,2. Numerous studies have been conducted regarding stroke using GMS models, whereas there are few studies that have used white matter stroke (WMS) models. White matter in rodents is substantially less than the white matter in humans or primates. Consequently, it is more difficult to selectively access and destroy the target regions in the white matter3. Additionally, no efficient tools have been developed to date to selectively destroy the planned extent of targeted white matter. Therefore, there has been lack of appropriate models for study of white matter strokes.
Animal stroke models are often used to monitor the progress of motor recovery for development of new rehabilitative and therapeutic methods. It is ideal to utilize an animal model that exhibits a long-term neurological deficit concordant with the anatomical alterations demonstrated in human stroke4,5. In this regard, rapid recovery of the motor deficit and wide involvement of the brain following infarct lesioning may not be realistic in the pursuit of stroke research. Previous capsular infarct models have been made by the occlusion of the internal carotid or anterior choroidal arteries and diffusion of endothelin-1 (ET-1) into the internal capsule6-9. Nonetheless, artery occlusion requires careful dissection of arteries, but it produces a wide area of infarct lesion, including the internal capsule, without persistent behavioral deficits. Moreover, ET-1 was not diffused to completely destroy the posterior limb of the internal capsule, and hence less marked or persisting behavioral deficit.
A photothrombotic infarction model has been widely used to generate various types of infarct lesions in the cortex and subcortical structures10. The technique include intravenous administration followed by focal illumination, which leads to platelet aggregation in the small vessels and generation of infarct lesions10. Photothrombotic technique has been extensively used to create GMS lesions, whereas it has rarely been used to generate WMS lesions5,11. For this technique, a combination of Rose Bengal dye and light irradiation has been demonstrated to be useful in destruction of the target structure, causing corresponding functional deficits. The key element of the photothrombotic technique is light irradiation, because it determines the size of infarct lesions. Light irradiation results in different effects on gray matter and white matter, because the scattering of light is more than 4 times higher in white matter compared with gray matter12; Accordingly, if the light intensity has a sufficiently low irradiance (&#60;1,140 mW/mm2), one can limit the extension to which photothrombotic lesion affect the extent to the white matter (i.e., internal capsule). For example, light of higher energy can induce infarcts in both gray and white matter, yet lower energy light may induce photothrombosis only in white matter. Furthermore, the penetration of light energy was very limited. Approximately 99% of light energy was lost beyond 1 mm from the source of light13. Therefore, it is expected that accurately targeted, lower energy light induces photothrombosis only in the white matter with a minimal encroachment of the neighboring gray matter.
Here, we describe a novel method to create infarct lesions in the forelimb area of the internal capsule in rodents. We describe the method of identification of the forelimb area in the internal capsule, the technology of light irradiation, including the adjustment and delivery of light, and the generation of an infarct lesion. We also describe behavioral testing used to evaluate the completeness of the capsular modeling.

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circumscribed capsular infarct modeling using a photothrombotic technique

Recent increase in the prevalence rate of white matter stroke demands specific research in the field. However, the lack of a pertinent animal model for white matter stroke has hampered research investigations. Here, we describe a novel method for creating a circumscribed capsular infarct that minimizes damage to neighboring gray matter structures. We used pre-surgery neural tracing with adeno-associated virus-green fluorescent protein (AAV-GFP) to identify somatotopic organization of the forelimb area within the internal capsule. The adjustment of light intensity based on different optical properties of gray and white matter contributes to selective destruction of white matter with relative preservation of gray matter. Accurate positioning of optical-neural interface enables destruction of entire forelimb area in the internal capsule, which leads to a marked and persistent motor deficit. Thus, this technique produces highly replicable capsular infarct lesions with a persistent motor deficit. The model will be helpful not only to study white matter stroke (WMS) at the behavioral, circuit, and cellular levels, but also to assess its usefulness for development of new therapeutic and rehabilitative interventions.

&#160; The method presented here is intended to create a circumscribed capsular infarct with a persistent motor deficit. Therefore, it is critical to correctly determine the target within the internal capsule in the pre-surgery step. The somatotopic mapping of pyramidal fibers in the internal capsule has not been settled to date. To correctly identify the target within the internal capsule, the forelimb area must be delineated. An injection of AAV-GFP into the forelimb area of the motor c...

Watch this Scientific Journal Video about Circumscribed Capsular Infarct Modeling Using a Photothrombotic Technique at JoVE.com

Circumscribed Capsular Infarct Modeling Using a Photothrombotic Technique

This manuscript describes a modeling technique of capsular infarct. Here we utilized a modified photothrombotic technique with low intensity of light after pre-surgery target mapping. Using this technique, we created a circumscribed capsular infarct model with persistent motor impairment.

Recent increase in the prevalence rate of white matter stroke demands specific research in the field. However, the lack of a pertinent animal model for ...

The overall goal of this technique is to create a circumscribed capsular infarct model with a persistent motor impairment using photothrombotic technique. Before creating the capsular infarct, it is necessary to identify the forelimb area in the internal capsule by introducing an adeno-associated virus expressing GFP to the forelimb area of the motor cortex. Begin by placing an anesthetized rat into a stereotaxic frame.Then shave the head of the rat and sterilize the scalp using 70%alcohol and povidone and iodine solution. Inject 2%lidocaine hydro chloride under the scalp in the area of the intended scalp incision to reduce intra operative pain. Apply ophthalmic ointment to prevent drying of the eyes.And place a sterile drape over the animal. After making a mid line incision of two centimeters in the scalp, position the stereotaxic arm to identify the forelimb area of the motor cortex according to the stereotaxic coordinates. Drill an entry hole at this position.Move the needle to the drilled hole and lower the needle one millimeter through the dura and into the motor cortex. Use a high precision micro pump to slowly inject one micro liter of virus. Leave the needle in place for an additional 10 minutes to prevent back flow up the needle tract.Once 10 minutes have elapsed, slowly withdraw the needle. After cleaning the operative site with saline irrigation, secure the wound with 3-0 nylon suture. Then release the rat from the stereotaxic frame and transfer it to a recovery chamber for monitoring.Administer analgesic for post operative pain control. After two to three weeks, sacrifice the rat according to approved methods and section the cryoprotected brain. After staining for GFP, observe the AAV-GFP transduced axons in the internal capsule with a fluorescent microscope.Compare the locations of transduced axons as seen on the fluorescent image with the rat brain atlas to accurately determine the stereotaxic coordinates of the transduced axons. To prepare the optical neural interface, first use a cutting drill to cut approximately four centimeters of a 27 gauge spinal needle with a stylet inside. Then strip 10 centimeters of the jacket of an optical fiber.Insert the un-jacketed piece of the optical fiber into a metal tube. And clamp the tube around the fiber. Then use a presser to clamp the lower 1/2 of the metal tube twice.The metal tube fills the space between the optical fiber and the hub of the spinal needle. Apply heat curable epoxy on the optical fiber. Apply additional epoxy to the empty space in the hub.And insert the optical fiber into the spinal needle. Cure the epoxy for 20 minutes at 100 degrees Celsius for stable fixation. Once cured, cleave the optical fiber that protrudes out of the spinal needle and then use diamond lapping sheets to polish the optical fiber at the tip of the spinal needle.Lastly, connect the FCPC connector part of the patch cord to the coupler of the green laser system. Then use a digital optical power and energy meter to measure the light intensity from the tip of the optical fiber to ensure accurate emission of light. Place a heat pad under the body of the animal to maintain body temperature at 37.5 degrees Celsius thought the surgery.Begin by anesthetizing and preparing the rat for surgery as before. After making a mid line incision of two centimeters, adjust the height of the nose clamp until the Bregma and Lambda are aligned at the same level. The correct alignment is critical to correctly target the internal capsule.Position the stereotaxic arm to locate the site for photothrombosis. Then drill a two millimeter hole at this point. Next, polish and clean the optical fiber tip of the ONI, then fix it to the stereotaxic frame without bending.Check the tip of the ONI to ensure it is clean and intact. Measure the laser intensity from the tip of the optical fiber prior to the insertion of the optical interface to the target site of the rat brain. Adjust the laser intensity to 3.5 milliwatts at the tip of the optical fiber.Now, lower the ONI into the target area of the internal capsule using the dorsoventral coordinate determined in the first section of the protocol. Then, inject two milligrams per kilogram of Rose Bengal through the tail vein and then start a countdown timer set to one minute. When the minute has elapsed, turn on the 532 nano-meter green laser for 90 seconds to create the infarct.After a radiation, gently remove the ONI from the brain. After cleaning the operative site, secure the wound with 3-0 nylon suture. Then remove the rat from the stereotaxic frame and transfer it to a recovery chamber.This image shows the extent of infarct lesions across varying intensities of laser light from two milliwatts to five milliwatts two weeks after photothrombotic lesioning. Arrows indicate the infarct lesion. The optical light intensity is considered to be between three milliwatts and four milliwatts in this experimental setting.The next two images show the microscopic appearance of the capsular infarct three weeks after photothrombosis. In this coronal section of the rat brain, the arrow heads indicate the tract of the needle containing the optical fiber in the thalamus and up to the internal capsule. These serial nestled stained sections show the extent of the infarct lesion in the internal capsule.The arrows indicate the infarct lesion.

circumscribed-capsular-infarct-modeling-using-photothrombotic

Research

JoVE Journal

Medicine

A Novel Capsulorhexis Technique Using Shearing Forces with Cystotome

Purpose:
To demonstrate a capsulorhexis technique using predominantly shearing forces with a cystotome on a virtual reality simulator and on a human eye.
Method:
Our technique involves creating the initial anterior capsular tear with a cystotome to raise a flap. The flap left unfolded on the lens surface. The cystotome tip is tilted horizontally and is engaged on the flap near the leading edge of the tear. The cystotome is moved in a circular fashion to direct the vector forces. The loose flap is constantly swept towards the centre so that it does not obscure the view on the tearing edge.
Results:
Our technique has the advantage of reducing corneal wound distortion and subsequent anterior chamber collapse. The capsulorhexis flap is moved away from the tear leading edge allowing better visualisation of the direction of tear. This technique offers superior control of the capsulorhexis by allowing the surgeon to change the direction of the tear to achieve the desired capsulorhexis size.
Conclusions:
The EYESI Surgical Simulator is a realistic training platform for surgeons to practice complex capsulorhexis techniques. The shearing forces technique is a suitable alternative and in some cases a far better technique in achieving the desired capsulorhexis.

This video demonstrates a novel capsulorhexis technique in modern cataract surgery. Capsulorhexis is the most difficult and important part of phacoemulsification surgery.

Purpose:
To demonstrate a capsulorhexis technique using predominantly shearing forces with a cystotome on a virtual reality simulator and on a human eye....

A Novel Technique of Rescuing Capsulorhexis Radial Tear-out using a Cystotome

Part 1 : Purpose: To demonstrate a capsulorhexis radial tear out rescue technique using a cystotome on a virtual reality cataract surgery simulator and in a human eye. Part 2 : Method: Steps: When a capsulorhexis begins to veer radially towards the periphery beyond the pupillary margin the following steps should be applied without delay. 2.1) Stop further capsulorhexis manoeuvre and reassess the situation. 2.2) Fill the anterior chamber with ophthalmic viscosurgical device (OVD). We recommend mounting the cystotome to a syringe containing OVD so that the anterior chamber can be reinflated rapidly. 2.3) The capsulorhexis flap is then left unfolded on the lens surface. 2.4) The cystotome tip is tilted horizontally to avoid cutting or puncturing the flap and is engaged on the flap near the leading edge of the tear but not too close to the point of tear. 2.5) Gently push or pull the leading edge of tear opposite to the direction of tear. 2.6) The leading tearing edge will start to do a 'U-Turn'. Maintain the tension on the flap until the tearing edge returns to the desired trajectory. Part 3 : Results: Using our technique, a surgeon can respond instantly to radial tear out without having to change surgical instruments. Changing surgical instruments at this critical stage runs a risk of further radial tear due to sudden shallowing of anterior chamber as a result of forward pressure from the vitreous. Our technique also has the advantage of reducing corneal wound distortion and subsequent anterior chamber collapse. Part 4 : Discussion The EYESI Surgical Simulator is a realistic training platform for surgeons to practice complex capsulorhexis tear-out techniques. Capsulorhexis is the most important and complex part of phacoemulsification and endocapsular intraocular lens implantation procedure. A successful cataract surgery depends on achieving a good capsulorhexis. During capsulorhexis, surgeons may face a challenging situation like a capsulorhexis radial tear-out. A surgeon must learn to tackle the problem promptly without making the situation worse. Some other methods of rescuing the situation have been described using a capsulorhexis forceps. However, we believe our method is quicker, more effective and easier to manipulate as demonstrated on the EYESi surgical simulator and on a human eye. Acknowledgments: List acknowledgements and funding sources. We would like to thank Dr. Wael El Gendy, for video clip. Disclosures: describe potential conflicting interests or state We have nothing to disclose. References: 1. Brian C. Little, Jennifer H. Smith, Mark Packer. J Cataract Refract Surg 2006; 32:1420 1422, Issue-9. 2. Neuhann T. Theorie und Operationstechnik der Kapsulorhexis. Klin Monatsbl Augenheilkd. 1987; 1990: 542-545. 3. Gimbel HV, Neuhann T. Development, advantages and methods of the continuous circular capsulorhexis technique. J Cataract Refract Surg. 1990; 16: 31-37. 4. Gimbel HV, Neuhann T. Continuous curvilinear capsulorhexis. (letter) J Cataract Refract Sur. 1991; 17: 110-111.

Capsulorhexis is an important step in phacoemulsification surgery. A surgeon creates a continous curvilinear tear on the anterior lens capsule by controlling the tearing vector forces. A peripherally extended tear is a serious complication. This video demonstrates a novel technique of rescuing capsular radial tear out using a cystotome.

Part 1 : Purpose:   To demonstrate a capsulorhexis radial tear out rescue technique using a cystotome on a virtual reality cataract surgery simulator and ...

Mouse Model of Intraluminal MCAO: Cerebral Infarct Evaluation by Cresyl Violet Staining

Stroke is the third cause of mortality and the leading cause of disability in the World. Ischemic stroke accounts for approximately 80% of all strokes. However, the thrombolytic tissue plasminogen activator (tPA) is the only treatment of acute ischemic stroke that exists. This led researchers to develop several ischemic stroke models in a variety of species. Two major types of rodent models have been developed: models of global cerebral ischemia or focal cerebral ischemia. To mimic ischemic stroke in patients, in whom approximately 80% thrombotic or embolic strokes occur in the territory of the middle cerebral artery (MCA), the intraluminal middle cerebral artery occlusion (MCAO) model is quite relevant for stroke studies. This model was first developed in rats by Koizumi et al. in 1986 1. Because of the ease of genetic manipulation in mice, these models have also been developed in this species 2-3.
	Herein, we present the transient MCA occlusion procedure in C57/Bl6 mice. Previous studies have reported that physical properties of the occluder such as tip diameter, length, shape, and flexibility are critical for the reproducibility of the infarct volume 4. Herein, a commercial silicon coated monofilaments (Doccol Corporation) have been used. Another great advantage is that this monofilament reduces the risk to induce subarachnoid hemorrhages. Using the Zeiss stereo-microscope Stemi 2000, the silicon coated monofilament was introduced into the internal carotid artery (ICA) via a cut in the external carotid artery (ECA) until the monofilament occludes the base of the MCA. Blood flow was restored 1 hour later by removal of the monofilament to mimic the restoration of blood flow after lysis of a thromboembolic clot in humans. The extent of cerebral infarct may be evaluated first by a neurologic score and by the measurement of the infarct volume. Ischemic mice were thus analyzed for their neurologic score at different post-reperfusion times. To evaluate the infarct volume, staining with 2,3,5-triphenyltetrazolium chloride (TTC) was usually performed. Herein, we used cresyl violet staining since it offers the opportunity to test many critical markers by immunohistochemistry. In this video, we report the MCAO procedure; neurological scores and the evaluation of the infarct volume by cresyl violet staining.

The intraluminal middle cerebral occlusion model in mice is herein presented. The extent of cerebral infarct is evaluated by a neurologic score and cresyl violet staining, an alternative staining to TTC, offering the great advantage to test in parallel many interest markers.

Stroke is the third  cause of mortality and the leading cause of disability in the World. Ischemic  stroke accounts for approximately 80% of all strokes. ...

Photothrombotic Ischemia: A Minimally Invasive and Reproducible Photochemical Cortical Lesion Model for Mouse Stroke Studies

The photothrombotic stroke model aims to induce an ischemic damage within a given cortical area by means of photo-activation of a previously injected light-sensitive dye. Following illumination, the dye is activated and produces singlet oxygen that damages components of endothelial cell membranes, with subsequent platelet aggregation and thrombi formation, which eventually determines the interruption of local blood flow. This approach, initially proposed by Rosenblum and El-Sabban in 1977, was later improved by Watson in 1985 in rat brain and set the basis of the current model. Also, the increased availability of transgenic mouse lines further contributed to raise the interest on the photothrombosis model. Briefly, a photosensitive dye (Rose Bengal) is injected intraperitoneally and enters the blood stream. When illuminated by a cold light source, the dye becomes activated and induces endothelial damage with platelet activation and thrombosis, resulting in local blood flow interruption. The light source can be applied on the intact skull with no need of craniotomy, which allows targeting of any cortical area of interest in a reproducible and non-invasive way. The mouse is then sutured and allowed to wake up. The evaluation of ischemic damage can be quickly accomplished by triphenyl-tetrazolium chloride or cresyl violet staining. This technique produces infarction of small size and well-delimited boundaries, which is highly advantageous for precise cell characterization or functional studies. Furthermore, it is particularly suitable for studying cellular and molecular responses underlying brain plasticity in transgenic mice.

Photothrombosis is a quick, minimally-invasive technique for inducing small and well-delimited infarction in areas of interest in highly reproducible manner. It is particularly suitable for studying cellular and molecular responses underlying brain plasticity in transgenic mice.

The photothrombotic stroke model aims to induce an ischemic damage within a given cortical area by means of photo-activation of a previously injected ...

Murine Cervical Heart Transplantation Model Using a Modified Cuff Technique

Mouse models are of special interest in research since a wide variety of monoclonal antibodies and commercially defined inbred and knockout strains are available to perform mechanistic in vivo studies. While heart transplantation models using a suture technique were first successfully developed in rats, the translation into an equally widespread used murine equivalent was never achieved due the technical complexity of the microsurgical procedure. In contrast, non-suture cuff techniques, also developed initially in rats, were successfully adapted for use in mice1-3. This technique for revascularization involves two major steps I) everting the recipient vessel over a polyethylene cuff; II) pulling the donor vessel over the formerly everted recipient vessel and holding it in place with a circumferential tie. This ensures a continuity of the endothelial layer, short operating time and very high patency rates4.
Using this technique for vascular anastomosis we performed more than 1,000 cervical heart transplants with an overall success rate of 95%. For arterial inflow the common carotid artery and the proximal aortic arch were anastomosed resulting in a retrograde perfusion of the transplanted heart. For venous drainage the pulmonary artery of the graft was anastomosed with the external jugular vein of the recipient5.
Herein, we provide additional details of this technique to supplement the video.

The murine cervical heart transplantation model is well suited for immunological as well as ischemia reperfusion injury studies. We modified the procedure using a non-suture cuff technique and performed more than 1,000 successful transplants with this approach.
Herein, we provide additional details of this technique to supplement the video.

Mouse models are of special interest in research since a wide variety of monoclonal antibodies and commercially defined inbred and knockout strains are ...

Human Skeletal Muscle Biopsy Procedures Using the Modified Bergstr&#246;m Technique

The percutaneous biopsy technique enables researchers and clinicians to collect skeletal muscle tissue samples. The technique is safe and highly effective. This video describes the percutaneous biopsy technique using a modified Bergstr&#246;m needle to obtain skeletal muscle tissue samples from the vastus lateralis of human subjects. The Bergstr&#246;m needle consists of an outer cannula with a small opening (&#8216;window&#8217;) at the side of the tip and an inner trocar with a cutting blade at the distal end. Under local anesthesia and aseptic conditions, the needle is advanced into the skeletal muscle through an incision in the skin, subcutaneous tissue, and fascia. Next, suction is applied to the inner trocar, the outer trocar is pulled back, skeletal muscle tissue is drawn into the window of the outer cannula by the suction, and the inner trocar is rapidly closed, thus cutting or clipping the skeletal muscle tissue sample. The needle is rotated 90&#176;&#160;and another cut is made. This process may be repeated three more times. This multiple cutting technique typically produces a sample of 100-200 mg or more in healthy subjects and can be done immediately before, during, and after a bout of exercise or other intervention. Following post-biopsy dressing of the incision site, subjects typically resume their activities of daily living right away and can fully participate in vigorous physical activity within 48-72 hr. Subjects should avoid heavy resistance exercise for 48 hr to reduce the risk of herniation of the muscle through the incision in the fascia.

Human Skeletal Muscle Biopsy Procedures Using the Modified Bergstr&amp;#246;m Technique

The purpose of this video is to present the modified Bergstr&#246;m skeletal muscle biopsy technique on human subjects.

The percutaneous biopsy technique enables researchers and clinicians to collect skeletal muscle tissue samples. The technique is safe and highly ...

Using a Laminating Technique to Perform Confocal Microscopy of the Human Sclera

The sclera is a dense connective tissue that covers and protects the eye. It mainly consists of dense collagen bundles (types I, III, IV, V, VI, and VII). Due to its autofluorescence, opaqueness, and thickness, it has not been found suitable for confocal microscopy. An alternative approach to the one presented here, which uses formalin-fixed sclera embedded in paraffin for immunohistochemistry, has technical challenges, especially when preheating the tissue for antigen retrieval. Since the sclera is relatively poor in both cells and vessels, the use of larger tissue samples was explored to help prevent overlooking cells and to understand their localization in relation to vessels and other anatomical sites. To allow for the analysis of larger tissue samples under the confocal microscope, a laminating technique was performed to create thin layers from the sclera. Following the analysis of results of CD31 blood vessels and lymphatic vessel endothelial hyaluronan receptor 1 (LYVE1) positive cells, for which approval for scientific examination was obtained, the advantages and limitations of this method are discussed.

Human sclera tissue is mainly collagen; therefore, it is not easily usable for immunohistochemistry. To achieve the goal of performing immunohistochemistry for confocal microscopy of scleral tissue, a laminating technique was used.


The sclera is a dense connective tissue that covers and protects the eye. It mainly consists of dense collagen bundles (types I, III, IV, V, VI, and ...

Induction of Ischemic Stroke and Ischemia-reperfusion in Mice Using the Middle Artery Occlusion Technique and Visualization of Infarct Area

Cerebrovascular disease is highly prevalent in the global population and encompasses several types of conditions, including stroke. To study the impact of stroke on tissue injury and to evaluate the effectiveness of therapeutic interventions, several experimental models in a variety of species were developed. They include complete global cerebral ischemia, incomplete global ischemia, focal cerebral ischemia, and multifocal cerebral ischemia. The model described in this protocol is based on the middle cerebral artery occlusion (MCAO) and is related to the focal ischemia category. This technique produces consistent focal ischemia in a strictly defined region of the hemisphere and is less invasive than other methods. The procedure described is performed on mice, given the availability of several genetic variants and the high number of tests standardized for mice to aid in the behavioral and neurodeficit evaluation.

We describe a mouse model of stroke induced by the occlusion of the middle cerebral artery using a silicone coated suture. The protocol can be applied to induce permanent occlusion or a temporary ischemia, followed by reperfusion.

Cerebrovascular disease is highly prevalent in the global population and encompasses several types of conditions, including stroke. To study the impact of ...

Histological Quantification of Chronic Myocardial Infarct in Rats

Myocardial infarction is defined as cardiomyocyte death due to prolonged ischemia; an inflammatory response and scar formation (fibrosis) follow the ischemic injury. Following the initial acute phase, chronic remodeling of the left ventricle (LV) modifies the structure and function of the heart. Permanent coronary ligation in small animals has been widely used as a reference model for a chronic model of MI. Thinning of the infarcted wall progressively develops to transmural fibrosis. Histological assessment of infarct size is commonly performed; nevertheless, a standardization of the methods for quantification is missing. Indeed, important methodological aspects, such as the number of sections analyzed and the sampling and quantification methods, are usually not described and therefore preclude comparison across investigations. Too often, quantification is performed on a single section obtained at the level of the papillary muscles. Because novel strategies aimed at reducing infarct expansion and remodeling are under investigation, there is an important need for the standardization of accurate heart sampling protocols. We describe an accurate method to quantify the infarct size using a systematic sampling of harvested rat heart and image analyses of trichromatic stained histological sections obtained from base to apex. We also provide evidence that calculating the expansion index (EI) allowed for infarct size assessment, taking into account changes of the left ventricle throughout the remodeling.

The post-mortem assessment of myocardial infarction (MI) in rodents is based on quantification of the infarct on stained heart sections. We describe an accurate method to quantify the infarct size using systematic sampling of harvested rat hearts from base to apex and image analyses of trichrome-stained histological sections.

Myocardial infarction is defined as cardiomyocyte death due to prolonged ischemia; an inflammatory response and scar formation (fibrosis) follow the ...

Mouse Model for Pancreas Transplantation Using a Modified Cuff Technique

Mouse models have several advantages in transplantation research, including easy handling, a variety of genetically well-defined strains, and the availability of the widest range of molecular probes and reagents to perform in vivo as well as in vitro studies. Based on our experience with various murine transplantation models, we developed a heterotopic pancreas transplantation model in mice with the intent to analyze mechanisms underlying severe ischemia reperfusion injury-associated early graft damage. In contrast to previously described techniques using suture techniques, herein we describe a new procedure using a non-suture cuff technique. 
In recent years, we have performed more than 300 pancreas transplantations in mice with an overall success rate of &gt;90%, a success rate never described before in mouse pancreas transplantation. The backbone of this non-suture cuff technique for graft revascularization consists of two major steps: (I) pulling the recipient vessel over a polyethylene/polyamide cuff and fixing it with a circumferential ligature, and (II) placing the donor vessel over the everted recipient vessel and fixing it with a second circumferential ligature. The resultant continuity of the endothelial layer results in less thrombogenic lesions with high patency rates and, finally, high success rates.
In this model, arterial anastomosis is achieved by pulling the abdominal aorta of the donor graft over the everted common carotid artery of the recipient animal. Venous drainage of the graft is achieved by pulling the portal vein of the graft over the everted external jugular vein of the recipient. This manuscript provides details and crucial steps of the organ recovery and organ implantation procedures, which will allow researchers with microsurgical skills to perform the transplantation successfully in their laboratories.

Among abdominal solid organ transplantation, pancreatic grafts are prone to develop severe ischemia reperfusion injury-associated graft damage, leading eventually to early graft loss. This protocol describes a model of murine pancreas transplantation using a non-suture cuff technique, ideally suited for analyzing these early, deleterious damages.