Name: mongolian gerbils as an animal model of wound healing
Uploaded: 2023-01-06T12:30:00
Description: Watch this Scientific Journal Video about Mongolian Gerbils as an Animal Model of Wound Healing at JoVE.com

We would like to thank engineer Rodrigo de la Fuente for his invaluable help and technical support. We also thank Mar&#237;a Eugenia Corbela for the narration and Priscilla Hazr&#250;n for the edition of the figures. Hugo Luj&#225;n allowed us to use the facilities at the Center for Research and Development in Immunology and Infectious Diseases (CIDIE).

All research procedures were approved by the &#34;Institutional Commission for the Care and Use of Laboratory Animals&#34; of Universidad Cat&#243;lica de C&#243;rdoba and followed the National Research Council Guide for the care and use of laboratory animals. These procedures were also approved by the authorities of the &#34;Facultad de Ciencias de la Salud&#34; of Universidad Cat&#243;lica de C&#243;rdoba and &#34;Instituto de la Visi&#243;n Cerro&#34;.
1. Gerbil handling and anesthesi...

<ol>
	<li>Kuo, I. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Corneal+wound+healing.">Corneal wound healing.</a> Current Opinion in Ophthalmology. 15 (4), 311-315 (2004).</li><li>Agrawal, V. B., Tsai, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Corneal+epithelial+wound+healing.">Corneal epithelial wound healing.</a> Indian Journal of Ophthalmology. 51 (1), 5-15 (2003).</li><li>Lu, L., Reinach, P. S., Kao, W. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Corneal+epithelial+wound+healing.">Corneal epithelial wound healing.</a> Experimental Biology and Medicine. 226 (7), 653-664 (2001).</li><li>Rathi, V. M., Vyas, S. P., Sangwan, V. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phototherapeutic+keratectomy.">Phototherapeutic keratectomy.</a> Indian Journal of Ophthalmology. 60 (1), 5-14 (2012).</li><li>Baumeister, M., B&#252;hren, J., Ohrloff, C., Kohnen, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Corneal+re-epithelialization+following+phototherapeutic+keratectomy+for+recurrent+corneal+erosion+as+in+vivo+model+of+epithelial+wound+healing.">Corneal re-epithelialization following phototherapeutic keratectomy for recurrent corneal erosion as in vivo model of epithelial wound healing.</a> Ophthalmologica. 223 (6), 414-418 (2009).</li><li>Fagerholm, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phototherapeutic+keratectomy:+12+years+of+experience.">Phototherapeutic keratectomy: 12 years of experience.</a> Acta Ophthalmologica Scandinavica. 81 (1), 19-32 (2003).</li><li>Mohan, R. R., Stapleton, W. M., Sinha, S., Netto, M. V., Wilson, S. 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+novel+method+for+generating+corneal+haze+in+anterior+stroma+of+the+mouse+eye+with+the+excimer+laser.">A novel method for generating corneal haze in anterior stroma of the mouse eye with the excimer laser.</a> Experimental Eye Research. 86 (2), 235-240 (2008).</li><li>Shah, D., Aakalu, V. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Murine+corneal+epithelial+wound+modeling.">Murine corneal epithelial wound modeling.</a> Methods in Molecular Biology. 2193, 175-181 (2021).</li><li>Zorio, D. A. R., 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=De+novo+sequencing+and+initial+annotation+of+the+Mongolian+gerbil+(Meriones+unguiculatus)+genome.">De novo sequencing and initial annotation of the Mongolian gerbil (Meriones unguiculatus) genome.</a> Genomics. 111 (3), 441-449 (2019).</li><li>Kalha, S., Kuony, A., Michon, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Corneal+epithelial+abrasion+with+ocular+burr+as+a+model+for+cornea+wound.">Corneal epithelial abrasion with ocular burr as a model for cornea wound.</a> Journal of Visualized Experiments. (137), e58071 (2018).</li><li>Yang, S., 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=The+electroretinogram+of+Mongolian+gerbil+(Meriones+unguiculatus.):+Comparison+to+mouse.">The electroretinogram of Mongolian gerbil (Meriones unguiculatus.): Comparison to mouse.</a> Neuroscience Letters. 589, 7-12 (2015).</li><li>Baker, A. G., Emerson, V. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Grating+acuity+of+the+Mongolian+gerbil+(Meriones+unguiculatus).">Grating acuity of the Mongolian gerbil (Meriones unguiculatus).</a> Behavioural Brain Research. 8 (2), 195-209 (1983).</li><li>Govardovskii, V. I., R&#246;hlich, P., Sz&#233;l, A., Khokhlova, T. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cones+in+the+retina+of+the+Mongolian+gerbil,+Meriones+unguiculatus:+An+immunocytochemical+and+electrophysiological+study.">Cones in the retina of the Mongolian gerbil, Meriones unguiculatus: An immunocytochemical and electrophysiological study.</a> Vision Research. 32 (1), 19-27 (1992).</li><li>Zanandr&#233;a, L. I., Oliveira, G. M., Abreu, A. S., Pereira, F. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ocular+lesions+in+gerbils+(Meriones+unguiculatus)+infected+with+low+larval+burden+of+Toxocara+canis:+Observations+using+indirect+binocular+ophthalmoscopy.">Ocular lesions in gerbils (Meriones unguiculatus) infected with low larval burden of Toxocara canis: Observations using indirect binocular ophthalmoscopy.</a> Revista da Sociedade Brasileira de Medicina Tropical. 41 (6), 570-574 (2008).</li><li>Cheng, S., 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=Enhancement+of+de+novo+sequencing,+assembly+and+annotation+of+the+Mongolian+gerbil+genome+with+transcriptome+sequencing+and+assembly+from+several+different+tissues.">Enhancement of de novo sequencing, assembly and annotation of the Mongolian gerbil genome with transcriptome sequencing and assembly from several different tissues.</a> BMC Genomics. 20 (1), 903 (2019).</li><li>Henriksson, J. T., McDermott, A. M., Bergmanson, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dimensions+and+morphology+of+the+cornea+in+three+strains+of+mice.">Dimensions and morphology of the cornea in three strains of mice.</a> Investigative Ophthalmology and Visual Science. 50 (8), 3648-3654 (2009).</li><li>Panagiotopoulos, M., Gan, L., Fagerholm, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stroma+remodelling+during+healing+of+corneal+surface+irregularities+induced+by+PTK.">Stroma remodelling during healing of corneal surface irregularities induced by PTK.</a> Acta Ophthalmologica Scandinavica. 85 (4), 387-394 (2007).</li></ol>

The physiology of corneal wound healing is a balance between tissue regeneration and the maintenance of homeostasis. Excessive wound healing may lead to fibrosis and scarring, which ultimately may result in the loss of organ function. With the rapid evolution of corneal surgical procedures, the importance of understanding corneal wound healing and the physiological and pathological events involved cannot be overestimated11. 
Multiple research works claim that gerbils ha...

Some of the most important aspects of corneal wound healing, which are key concerns for anterior segment surgery, are the integrity of the epithelial architecture, the maintenance of the corneal stroma transparency, and, finally, the outcome in terms of the refractive properties of the cornea1.
The cornea is the outermost clear tissue at the front of the eyeball and is, therefore, susceptible to trauma, infections, and burns; the impaired healing of these wounds can compromise visual health2.
At present, several animal models are available to study corneal healing, and some of them are better than others, depending on the species and the type of mechanism to be studied1.&#160;There are a few records of previous investigations on the retina of gerbils2. However, so far, there is no published literature on the scarring processes in the cornea of these rodents.
Here, we present Meriones unguiculatus (Mongolian gerbil) as an animal model of wound healing in the cornea. Procedures to elicit corneal healing after photorefractive keratectomy are described, which allow us to study the different types of corneal scarring processes, understand wound healing in terms of the dynamic phases of living tissue, and, finally, plan appropriate future treatments3. Phototherapeutic keratectomy is a highly reproducible technique with the possibility of precisely controlling parameters such as the depth and diameter of the corneal injury4. Moreover, this technique does not require procedures with surgical instruments or chemical solutions (e.g., saline solution, formalin, alcohol, etc.) that may add variables that are specific to the instruments or to the operator performing the procedure5.
Three 6-month-old male gerbils of similar sizes and weights (approximately 90 g) were used for the experiment presented in this article. The procedures were only performed in the right eyes.One gerbil (referred to as gerbil 1 or control) did not undergo phototherapeutic keratectomy and was enucleated to evaluate all the normal ocular structures. Phototherapeutic keratectomy involves the controlled delivery of excimer laser-generated ultraviolet light to the cornea and was developed in order to perform refractive surgery6. It has been used in other rodents, such as mice7. The other two gerbils were subjected to phototherapeutic keratectomy. One of them was enucleated at 24 h (referred to as gerbil 2) and the other one at 96 h after surgery (referred to as gerbil 3).
To perform this experiment, a gerbil selected at random was filmed for each condition to be studied, but this experiment was previously performed with 16 gerbils in total for each condition. For editing reasons, it was decided to use a randomly selected gerbil for each condition (three gerbils in total) as an example.
The main objective of this research is to explore the best animal model available. However, it is important to note that not all species have eye characteristics similar to those of the human eye8. This article describes the methodology used to study the cornea of Meriones unguiculatus and the procedure performed to generate the corneal injury, which allow us to study the healing process.

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			<td>Anesthesia</td>
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			<td></td>
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			<td>Eppendorf tubes</td>
			<td>Tododrogas</td>
			<td></td>
			<td></td>
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		<tr>
			<td>Excimer Laser</td>
			<td>Technolas</td>
			<td>2022445</td>
			<td></td>
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		<tr>
			<td>Fluorescein</td>
			<td>Poen</td>
			<td></td>
			<td></td>
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		<tr>
			<td>Forceps</td>
			<td>Ofcor</td>
			<td>3339</td>
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			<td>Formaldehyde</td>
			<td>Tododrogas</td>
			<td></td>
			<td></td>
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		<tr>
			<td>Gloves</td>
			<td>Tododrogas</td>
			<td></td>
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			<td>Ketamine&#160;</td>
			<td>Sigma-Aldrich</td>
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			<td>Optical coherence tomography</td>
			<td>Optovue</td>
			<td>659007</td>
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			<td>Proparacaine</td>
			<td>Poen</td>
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			<td>Scisors</td>
			<td>Ofcor</td>
			<td>3336</td>
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			<td>Sterile drapes</td>
			<td>Soporte hospitalario</td>
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			<td>Sterile gauzes</td>
			<td>Soporte hospitalario</td>
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			<td></td>
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			<td>Syringes and needles</td>
			<td>Tododrogas</td>
			<td></td>
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			<td>Xylazine&#160;</td>
			<td>Sigma-Aldrich&#160;</td>
			<td></td>
			<td></td>
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mongolian gerbils as an animal model of wound healing

Corneal wound healing studies have been conducted for a long time and have helped to reduce suffering and develop treatments that contribute to improving patients' eye health. Historically, corneal healing has been studied in rodents such as mice and rats, but these models might not completely mimic human disorders. However, information on other rodents such as Mongolian gerbils (Meriones unguiculatus) is scant in corneal research.
Here, we describe a technique to develop a novel animal model for studying corneal healing after photorefractive keratectomy. Due to the limited literature available on the cornea of M. unguiculatus, we also describe a histological analysis of the normal cornea. These research techniques can also be employed in the study of eye diseases because of the similarity between the corneas of Mongolian gerbils and humans in terms of genetics, anatomy, and physiology.

In the present study, the entire corneal structure was thoroughly analyzed using histological techniques and complementary studies of the anterior segment, such as optical coherence tomography. The image analysis using optical coherence tomography of the anterior segment structures shows a normal epithelium and stroma (Figure 1), with central and peripheral corneal thicknesses of 160 &#181;m and 106 &#181;m &#177; 2 &#181;m, respectively. Other publications have also shown that the cornea of...

Watch this Scientific Journal Video about Mongolian Gerbils as an Animal Model of Wound Healing at JoVE.com

Mongolian Gerbils as an Animal Model of Wound Healing

This article describes a new animal model developed to study the anatomy and histology of the cornea and its healing processes. This new animal model uses the Mongolian gerbil, which has a cornea with many similarities to the human cornea.

Corneal wound healing studies have been conducted for a long time and have helped to reduce suffering and develop treatments that contribute to improving ...

Previous studies show that the photorefractive keratectomy or transepithelial PRK, is one of the best animal model for the study of corneal healing, and also, the changes associated to histopathological debridement of the epithelial cornea. Working with Mongolian gerbils as animal model has several advantages over other rodents. First, the cornea has the same histologic layers as the human cornea.Second, the eye is anatomically larger than the eye of other rodents, allowing for easier manipulation. All this research was carried out in the facilities of the Center for Research and Development in Immunology and Infectious Diseases of the Universidad Catolica De Cordoba. The first step was to disinfect the working surface of the laminar flow cabinet.For this purpose, 70%alcohol was used. Surgical instruments to be used. Disposable materials such as needles and syringes, and drugs to anesthetize the rodent, were placed in the work area.A disposable surgical field should also be placed to contain secretions and rodent hair if necessary. Three six-month old male Mongolian gerbils of similar size and weight, approximately 90 grams were used in the experiment. The procedures to be performed later were performed on the right eyes only.The cage with the rodent is taken and placed inside the laminar flow cabinet. We proceed to open the box, identify each of the gerbils, and weigh them on the scale. They're harmless but delicate animals.Disposable gloves should be worn at all times. For it correct handling, the operator should use his unskilled hand to hold it firmly by the tail, and with the skilled hand, gently press down with a thumb and index finger behind the ears to hold the animal and with the little finger, hold the tail. Based on the weight of the animal, the amount of anesthesia needed for each of the gerbils is calculated.A one milliliter syringe should be filled with ketamine, 50 over 100 milligram per kilogram, and xylazine, two milligram per kilogram. Prior to performing the optical coherence tomography, sterile surgical drapes were placed to protect the equipment from secretions or animal hair. While one of the operators hold the animal, another operator must take the captures.The eye was photographed microscopically and multiple slices were made of the interior segment of the rodent. The entire cornea, the anterior chamber, the iris, the iridocorneal angle and lens, which protrudes into the anterior chamber can be observed. In addition, central and peripheral corneal thickness measurements were taken showing a central thickness of 160 micrometers decreasing to approximately 110 micrometers in the periphery.Prior to perform excimer laser PTK, sterile surgical drapes were placed to protect the equipment from secretions or animal hair. Between 60 and 62 micrometers of corneal thickness were ablated at the diameter of three millimeters. The cornea was photographed to evaluate immediate morphologic changes.In this photograph, it can be seen, the eye eyeball of the gerbil right eye. A, irregular surface of the normal eye eyeball is observed. B, photograph taken five minutes after PTK was performed showing that the corneal surface presents irregularities.See evidence of the corneal ulcer stained with fluorescein. On the OCT, the right arrow mark the area where detritus has accumulated in the center and the left arrow mark the edge of the corneal ulcer. The method of sacrifice used in this experiment was through the use of a carbon dioxide chamber.They were sacrificed at different time intervals and enucleation of the normal eyeball and post-surgical eyeballs were performed at 24 and 96 hours post-surgery to observe corneal healing. Each enucleated eyeball was placed in formaldehyde and processed by a pathologist. Multiple sections, measurements and photographs were taken.Histologically, the corneal thickness consists with that obtained by OCT, and there is a progressive thinning towards the periphery. This is because the layers of epithelium and stromal fibers decrease in the periphery. The Mongolian gerbil cornea has the same layers as the human, stratified anterior epithelium with four to six layers of cells representing 28%of the total thickness of the cornea.Bowman's layer, stroma representing 66%of the total thickness. This cements membrane and endothelium. At 24 hours postsurgery, the corneal ulcer can be seen where the arrow is marked.Also observed multiple patches of epithelial achantholysis and isolated dyskeratocis, acute subepithelial inflammatory infiltrate, edema at the stromal level. The changes observed in the operated gerbil at 96 hours after PTK are, presence of increased edema, disaggregation of stromal fibers and cells, and it should be noted that the interior epithelium was already completely regenerated and did not present inflammatory infiltrate. The present study show the positive result of the current animal model in gerbils and confirming it as a new research option in corneal wound healing.To date, there are no publications that analyze, in detail, the anatomy and histology of the Mongolian gerbil cornea. Therefore, we hope that this animal model will be the basis for future scientific investigations.

mongolian-gerbils-as-an-animal-model-of-wound-healing

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A Simplified Technique for Producing an Ischemic Wound Model

One major obstacle in current diabetic wound research is a lack of an ischemic wound model that can be safely used in diabetic animals. Drugs that work well in non-ischemic wounds may not work in human diabetic wounds because vasculopathy is one major factor that hinders healing of these wounds. We published an article in 2007 describing a rabbit ear ischemic wound model created by a minimally invasive surgical technique. Since then, we have further simplified the procedure for easier operation. On one ear, three small skin incisions were made on the vascular pedicles, 1-2 cm from the ear base. The central artery was ligated and cut along with the nerve. The whole cranial bundle was cut and ligated, leaving only the caudal branch intact. A circumferential subcutaneous tunnel was made through the incisions, to cut subcutaneous tissues, muscles, nerves, and small vessels. The other ear was used as a non-ischemic control. Four wounds were made on the ventral side of each ear. This technique produces 4 ischemic wounds and 4 non-ischemic wounds in one animal for paired comparisons. After surgery, the ischemic ear was cool and cyanotic, and showed reduced movement and a lack of pulse in the ear artery. Skin temperature of the ischemic ear was 1-10 &deg;C lower than that on the normal ear and this difference was maintained for more than one month. Ear tissue high-energy phosphate contents were lower in the ischemic ear than the control ear. Wound healing times were longer in the ischemic ear than in the non-ischemic ear when the same treatment was used. The technique has now been used on more than 80 rabbits in which 23 were diabetic (diabetes time ranging from 2 weeks to 2 years). No single rabbit has developed any surgical complications such as bleeding, infection, or rupture in the skin incisions. The model has many advantages, such as little skin disruption, longer ischemic time, and higher success rate, when compared to many other models. It can be safely used in animals with reduced resistance, and can also be modified to meet different testing requirements.

We have developed a minimally invasive technique to create a rabbit ischemic ear wound model by dividing the central artery and nerve and the cranial neurovascular bundle. A subcutaneous tunnel then cuts all subcutaneous tissues. This procedure causes minimal skin disruption and can be safely used in diabetic animals.

One major obstacle in current diabetic wound research is a lack of an ischemic wound model that can be safely used in diabetic animals. Drugs that work ...

Murine Model of Wound Healing

Wound healing and repair are the most complex biological processes that occur in human life. After injury, multiple biological pathways become activated. Impaired wound healing, which occurs in diabetic patients for example, can lead to severe unfavorable outcomes such as amputation. There is, therefore, an increasing impetus to develop novel agents that promote wound repair. The testing of these has been limited to large animal models such as swine, which are often impractical. Mice represent the ideal preclinical model, as they are economical and amenable to genetic manipulation, which allows for mechanistic investigation. However, wound healing in a mouse is fundamentally different to that of humans as it primarily occurs via contraction. Our murine model overcomes this by incorporating a splint around the wound. By splinting the wound, the repair process is then dependent on epithelialization, cellular proliferation and angiogenesis, which closely mirror the biological processes of human wound healing. Whilst requiring consistency and care, this murine model does not involve complicated surgical techniques and allows for the robust testing of promising agents that may, for example, promote angiogenesis or inhibit inflammation. Furthermore, each mouse acts as its own control as two wounds are prepared, enabling the application of both the test compound and the vehicle control on the same animal. In conclusion, we demonstrate a practical, easy-to-learn, and robust model of wound healing, which is comparable to that of humans.

A murine model of cutaneous wound healing that can be used to assess therapeutic compounds in physiological and pathophysiological settings.

Wound healing and repair are the most complex biological processes that occur in human life. After injury, multiple biological pathways become activated. ...

Murine Endoscopy for In Vivo Multimodal Imaging of Carcinogenesis and Assessment of Intestinal Wound Healing and Inflammation

Mouse models are widely used to study pathogenesis of human diseases and to evaluate diagnostic procedures as well as therapeutic interventions preclinically. However, valid assessment of pathological alterations often requires histological analysis, and when performed ex vivo, necessitates death of the animal. Therefore in conventional experimental settings, intra-individual follow-up examinations are rarely possible. Thus, development of murine endoscopy in live mice enables investigators for the first time to both directly visualize the gastrointestinal mucosa and also repeat the procedure to monitor for alterations. Numerous applications for in vivo murine endoscopy exist, including studying intestinal inflammation or wound healing, obtaining mucosal biopsies repeatedly, and to locally administer diagnostic or therapeutic agents using miniature injection catheters. Most recently, molecular imaging has extended diagnostic imaging modalities allowing specific detection of distinct target molecules using specific photoprobes. In conclusion, murine endoscopy has emerged as a novel cutting-edge technology for diagnostic experimental in vivo imaging and may significantly impact on preclinical research in various fields.

Murine Endoscopy for In Vivo Multimodal Imaging of Carcinogenesis and Assessment of Intestinal Wound Healing and Inflammation

Small animal imaging techniques allow serial diagnostic examinations and therapeutic interventions in vivo. Recently, the scope of applications has significantly widened and currently includes assessment of colonic tumor development, wound healing and monitoring of inflammation. This protocol illustrates these diverse potential applications of murine endoscopy.

Mouse models are widely used to study pathogenesis of human diseases and to evaluate diagnostic procedures as well as therapeutic interventions ...

Demonstration of the Rat Ischemic Skin Wound Model

The propensity for chronic wounds in humans increases with ageing, disease conditions such as diabetes and impaired cardiovascular function, and unrelieved pressure due to immobility. Animal models have been developed that attempt to mimic these conditions for the purpose of furthering our understanding of the complexity of chronic wounds. The model described herein is a rat ischemic skin flap model that permits a prolonged reduction of blood flow resulting in wounds that become ischemic and resemble a chronic wound phenotype (reduced vascularization, increased inflammation and delayed wound closure). It consists of a bipedicled dorsal flap with 2 ischemic wounds placed centrally and 2 non-ischemic wounds lateral to the flap as controls. A novel addition to this ischemic skin flap model is the placement of a silicone sheet beneath the flap that functions as a barrier and a splint to prevent revascularization and reduce contraction as the wounds heal. Despite the debate of using rats for wound healing studies due to their quite distinct anatomic and physiologic differences compared to humans (i.e., the presence of a panniculus carnosus muscle, short life-span, increased number of hair follicles, and their ability to heal infected wounds) the modifications employed in this model make it a valuable alternative to previously developed ischemic skin flap models.

The rat, due to its size, availability, and rather docile behavior, has been utilized as a research model for many years. The goal of this protocol is to utilize the rat as an ischemic skin wound healing model to provide valuable insight into the pathophysiology of chronic wounds.

The propensity for chronic wounds in humans increases with ageing, disease conditions such as diabetes and impaired cardiovascular function, and ...

Bioluminescence Imaging of an Immunocompetent Animal Model for Glioblastoma

In contrast to commonly reported human glioma xenograft animal models, GL261 murine glioma xenografts recapitulate nearly all relevant clinical and histopathologic features of the human disease. When GL261 cells are implanted intracranially in syngeneic C57BL/6 mice, the model has the added advantage of maintaining an intact immune microenvironment. Stable expression of luciferase in GL261 cells allows non-invasive cost effective bioluminescence monitoring of intracranial tumor growth. We have recently demonstrated that luciferase expression in GL261 cells does not affect the tumor growth properties, tumor cell immunomodulatory cytokine expression, infiltration of immune cells into the tumor, or overall survival of animals bearing the intracranial tumor. Therefore, it appears that the GL261 luciferase glioma model can be useful in the study of novel chemotherapeutic and immunotherapeutic modalities. Here we report the technique for generating stable luciferase expression in GL261 cells and how to study the in vitro and in vivo growth of the tumor cells by bioluminescence imaging.

GL261 glioma cells provide a useful immunocompetent animal model of glioblastoma. The goals of this protocol are to demonstrate proper techniques for monitoring intracranial tumor growth using in vivo bioluminescence imaging, and to verify the utility of luciferase-modified GL261 cells for studying tumor immunology and immunotherapeutic approaches for treating glioblastoma.

In contrast to commonly reported human glioma xenograft animal models, GL261 murine glioma xenografts recapitulate nearly all relevant clinical and ...

Multimodal Quantitative Phase Imaging with Digital Holographic Microscopy Accurately Assesses Intestinal Inflammation and Epithelial Wound Healing

The incidence of inflammatory bowel disease, i.e., Crohn&#39;s disease and Ulcerative colitis, has significantly increased over the last decade. The etiology of IBD remains unknown and current therapeutic strategies are based on the unspecific suppression of the immune system. The development of treatments that specifically target intestinal inflammation and epithelial wound healing could significantly improve management of IBD, however this requires accurate detection of inflammatory changes. Currently, potential drug candidates are usually evaluated using animal models in vivo or with cell culture based techniques in vitro. Histological examination usually requires the cells or tissues of interest to be stained, which may alter the sample characteristics and furthermore, the interpretation of findings can vary by investigator expertise. Digital holographic microscopy (DHM), based on the detection of optical path length delay, allows stain-free quantitative phase contrast imaging. This allows the results to be directly correlated with absolute biophysical parameters. We demonstrate how measurement of changes in tissue density with DHM, based on refractive index measurement, can quantify inflammatory alterations, without staining, in different layers of colonic tissue specimens from mice and humans with colitis. Additionally, we demonstrate continuous multimodal label-free monitoring of epithelial wound healing in vitro, possible using DHM through the simple automated determination of the wounded area and simultaneous determination of morphological parameters such as dry mass and layer thickness of migrating cells. In conclusion, DHM represents a valuable, novel and quantitative tool for the assessment of intestinal inflammation with absolute values for parameters possible, simplified quantification of epithelial wound healing in vitro and therefore has high potential for translational diagnostic use.

Accurate assessment of anti-inflammatory effects is of utmost importance for the evaluation of potential new drugs for the treatment of inflammatory bowel disease. Digital holographic microscopy provides assessment of inflammation in murine and human colonic tissue samples as well as automated multimodal evaluation of epithelial wound healing in vitro.

The incidence of inflammatory bowel disease, i.e., Crohn&#39;s disease and Ulcerative colitis, has significantly increased over the last decade. The ...

Creation and Transplantation of an Adipose-derived Stem Cell (ASC) Sheet in a Diabetic Wound-healing Model

Artificial skin has achieved considerable therapeutic results in clinical practice. However, artificial skin treatments for wounds in diabetic patients with impeded blood flow or with large wounds might be prolonged. Cell-based therapies have appeared as a new technique for the treatment of diabetic ulcers, and cell-sheet engineering has improved the efficacy of cell transplantation. A number of reports have suggested that adipose-derived stem cells (ASCs), a type of mesenchymal stromal cell (MSC), exhibit therapeutic potential due to their relative abundance in adipose tissue and their accessibility for collection when compared to MSCs from other tissues. Therefore, ASCs appear to be a good source of stem cells for therapeutic use. In this study, ASC sheets from the epididymal adipose fat of normal Lewis rats were successfully created using temperature-responsive culture dishes and normal culture medium containing ascorbic acid. The ASC sheets were transplanted into Zucker diabetic fatty (ZDF) rats, a rat model of type 2 diabetes and obesity, that exhibit diminished wound healing. A wound was created on the posterior cranial surface, ASC sheets were transplanted into the wound, and a bilayer artificial skin was used to cover the sheets. ZDF rats that received ASC sheets had better wound healing than ZDF rats without the transplantation of ASC sheets. This approach was limited because ASC sheets are sensitive to dry conditions, requiring the maintenance of a moist wound environment. Therefore, artificial skin was used to cover the ASC sheet to prevent drying. The allogenic transplantation of ASC sheets in combination with artificial skin might also be applicable to other intractable ulcers or burns, such as those observed with peripheral arterial disease and collagen disease, and might be administered to patients who are undernourished or are using steroids. Thus, this treatment might be the first step towards improving the therapeutic options for diabetic wound healing.

Creation and Transplantation of an Adipose-derived Stem Cell ASC Sheet in a Diabetic Wound-healing Model

Adipose-derived stem cells (ASCs) are easily isolated and harvested from the fat of normal rats. ASC sheets can be created using cell-sheet engineering and can be transplanted into Zucker diabetic fatty rats exhibiting full-thickness skin defects with exposed bone and then covered with a bilayer of artificial skin.

Artificial skin has achieved considerable therapeutic results in clinical practice. However, artificial skin treatments for wounds in diabetic patients ...

Development of a Direct Pulp-capping Model for the Evaluation of Pulpal Wound Healing and Reparative Dentin Formation in Mice

Dental pulp is a vital organ of a tooth fully protected by enamel and dentin. When the pulp is exposed due to cariogenic or iatrogenic injuries, it is often capped with biocompatible materials in order to expedite pulpal wound healing. The ultimate goal is to regenerate reparative dentin, a physical barrier that functions as a "biological seal" and protects the underlying pulp tissue. Although this direct pulp-capping procedure has long been used in dentistry, the underlying molecular mechanism of pulpal wound healing and reparative dentin formation is still poorly understood. To induce reparative dentin, pulp capping has been performed experimentally in large animals, but less so in mice, presumably due to their small sizes and the ensuing technical difficulties. Here, we present a detailed, step-by-step method of performing a pulp-capping procedure in mice, including the preparation of a Class-I-like cavity, the placement of pulp-capping materials, and the restoration procedure using dental composite. Our pulp-capping mouse model will be instrumental in investigating the fundamental molecular mechanisms of pulpal wound healing in the context of reparative dentin in vivo by enabling the use of transgenic or knockout mice that are widely available in the research community.

We describe a step-by-step method of performing direct pulp capping on mice teeth for the evaluation of pulpal wound healing and reparative dentin formation in vivo.

Dental pulp is a vital organ of a tooth fully protected by enamel and dentin. When the pulp is exposed due to cariogenic or iatrogenic injuries, it is ...

Microscopy Based Methods for the Assessment of Epithelial Cell Migration During In Vitro Wound Healing

Cell migration is a mandatory aspect for wound healing. Creating artificial wounds on research animal models often results in costly and complicated experimental procedures, while potentially lacking in precision. In vitro culture of epithelial cell lines provides a suitable platform for researching the cell migratory behavior in wound healing and the impact of treatments on these cells. The physiology of epithelial cells is often studied in non-confluent conditions; however, this approach may not resemble natural wound healing conditions. Disrupting the epithelium integrity by mechanical means generates a realistic model, but may impede the application of molecular techniques. Consequently, microscopy based techniques are optimal for studying epithelial cell migration in vitro. Here we detail two specific methods, the artificial wound scratch assay and the artificial migration front assay, that can obtain quantitative and qualitative data, respectively, on the migratory performance of epithelial cells.

Microscopy Based Methods for the Assessment of Epithelial Cell Migration During  In Vitro Wound Healing

This manuscript describes how incision-like lesions made on cultured epithelial cell monolayers conveniently model wound healing in vitro, allowing for imaging by confocal or laser scanning microscopy, and which can provide high-quality quantitative and qualitative data for studying both cell behavior and the mechanisms involved in migration.

Cell migration is a mandatory aspect for wound healing. Creating artificial wounds on research animal models often results in costly and complicated ...

Isometric Contractility Measurement of the Mouse Mesenteric Artery Using Wire Myography

The wire myograph technique is used to assess the contractility of vascular smooth muscles in response to depolarization, GPCR agonists/inhibitors and drugs. It is widely used in many studies on the physiological functions of vascular smooth muscle, the pathogenesis of vascular diseases such as hypertension, and the development of smooth muscle relaxant drugs. The mouse is a widely used model animal with a large pool of disease models and genetically modified strains. We introduced this method to measure the isometric contraction of mouse mesenteric artery in detail. A 1.4-mm segment of mouse mesenteric resistance artery was isolated and mounted on a myograph chamber by passing two steel wires through its lumen. After equilibration and normalization steps, the vessel segment was potentiated by a high-K+ solution twice prior to the contraction assay. As an example of the application of this method in drug development, we measured the relaxant effect of a novel natural substance, neoliensinine, isolated from a Chinese herb, embryos of the lotus seed (Nelumbo nucifera Gaertn.) on mouse mesenteric arteries. The vessel segments mounted on the myograph chamber were stimulated with a high-K+ solution. When the force tension reached a stable sustained phase, cumulative doses of neoliensinine were added to the chamber. We found that neoliensinine had a dose-dependent relaxant effect on smooth muscle contraction, thus suggesting that it bears potential activity against hypertension. In addition, as the vessel segment can survive at least 4 hours after mounting and maintain contractility induced by the high-K+ solution for many times, we suggest that the wire myograph system may be used for the time-consuming process of drug screening.

The wire myograph technique is used to investigate vascular smooth muscle functions and screen new drugs. We report a detailed protocol for measuring the isometric contractility of the mouse mesenteric artery and for screening new relaxants of vascular smooth muscle.

The wire myograph technique is used to assess the contractility of vascular smooth muscles in response to depolarization, GPCR agonists/inhibitors and ...