Name: severe burn injury in a swine model for clinical dressing assessment
Uploaded: 2018-11-06T12:30:00
Description: Watch this Scientific Journal Video about Severe Burn Injury in a Swine Model for Clinical Dressing Assessment at JoVE.com

This study was supported by a grant from the Tri-Service General Hospital; National Defense Medical Center, Taiwan (TSGH-C107-042); Ministry of Science and Technology, Taiwan (MOST 106-2314-B-016 -014); and the National Defense Medical Center (MAB-106-055; MAB-106-010; MAB-107-064).

Procedures involving animal subjects have been approved by the Animal Care Committee at National Defense Medical Center, Taiwan (R.O.C). This study was conducted in the Laboratory Animal Center at the National Defense Medical Center. Swine weighing between 20 and 25 kg has been successfully instrumented using this protocol.
1. Adaptation of the Animals to Human Handling
<ol>
	<li>After arrival in the facility, house the animals solitarily but let them interact with each other.</li>
	<li>Prov...

<ol>
	<li>Sen, C. K., 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=Human+skin+wounds:+a+major+and+snowballing+threat+to+public+health+and+the+economy.">Human skin wounds: a major and snowballing threat to public health and the economy.</a> Wound Repair Regeneration. 17, 763-771 (2009).</li><li>Sen, C. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Wound+healing+essentials:+let+there+be+oxygen.">Wound healing essentials: let there be oxygen.</a> Wound Repair Regeneration. 17, 1-18 (2009).</li><li>Verhaegen, P. 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=Differences+in+collagen+architecture+between+keloid,+hypertrophic+scar,+normotrophic+scar,+and+normal+skin:+an+objective+histopathological+analysis.">Differences in collagen architecture between keloid, hypertrophic scar, normotrophic scar, and normal skin: an objective histopathological analysis.</a> Wound Repair Regeneration. 17, 649-656 (2009).</li><li>Swindle, M. M., Adams, 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=.">.</a> Experimental Surgery and Physiology: Induced Animal Models of Human Disease. , (1988).</li><li>Swindle, M. M., Smith, A. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Swine as Models in Biomedical Research. , (1992).</li><li>Tumbleson, M. E., Schook, L. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Advances in Swine in Biomedical Research. Vols 1-2. , (1996).</li><li>Wang, C. 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=Enhanced+wound-healing+performance+of+a+phyto-polysaccharide-enriched+dressing+-+a+preclinical+small+and+large+animal+study.">Enhanced wound-healing performance of a phyto-polysaccharide-enriched dressing - a preclinical small and large animal study.</a> International Wound Journal. 14, 1359-1369 (2017).</li><li>Rowan, M. P., Cancio, L. C., Elster, E. A., Burmeister, D. M., Rose, L. F., Natesan, S., Chan, R. K., Christy, R. J., Chung, K. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Burn+wound+healing+and+treatment:+review+and+advancements.">Burn wound healing and treatment: review and advancements.</a> Journal of Critical Care. 19, 243 (2015).</li><li>Wong, V. W., Sorkin, M., Glotzbach, J. P., Longaker, M. T., Gurtner, G. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surgical+approaches+to+create+murine+models+of+human+wound+healing.">Surgical approaches to create murine models of human wound healing.</a> Journal of Biomedicine and Biotechnology. 969618, 8 (2011).</li><li>Gaines, C., Poranki, D., Du, W., Clark, R. A., Van Dyke, M. <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+porcine+deep+partial+thickness+burn+model.">Development of a porcine deep partial thickness burn model.</a> Burns. 39, 311-319 (2013).</li><li>Gnyawali, S. C., Barki, K. G., Mathew-Steiner, S. S., Dixith, S., Vanzant, D., Kim, J., Dickerson, J. L., Datta, S., Powell, H., Roy, S., Bergdall, V., Sen, C. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-resolution+harmonics+ultrasound+imaging+for+non-invasive+characterization+of+wound+healing+in+a+pre-clinical+swine+model.">High-resolution harmonics ultrasound imaging for non-invasive characterization of wound healing in a pre-clinical swine model.</a> PLoS One. 10 (3), e0122327 (2015).</li><li>Eaglstein, W. H., Mertz, P. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=New+methods+for+assessing+epidermal+wound+healing:+the+effects+of+triamcinolone+acetonide+and+polyethelene+film+occlusion.">New methods for assessing epidermal wound healing: the effects of triamcinolone acetonide and polyethelene film occlusion.</a> Journal of Investigative Dermatology. 71, 332-384 (1978).</li><li>Swindle, M. M., Smith, A. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparative+anatomy+and+physiology+of+the+pig.">Comparative anatomy and physiology of the pig.</a> Scandinavian Journal of Laboratory Animal Sciences. 25, 1-10 (1998).</li><li>Swindle, M. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Swine in the Laboratory: Surgery, Anesthesia, Imaging and Experimental Techniques. , (2007).</li><li>Mertz, P. M., 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=IL-1+as+a+potent+inducer+of+wound+re-epithelization.">IL-1 as a potent inducer of wound re-epithelization.</a> Progress in Clinical and Biological Research. 365, 473-480 (1991).</li><li>Eming, S. A., Martin, P., Tomic-Canic, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Wound+repair+and+regeneration:+mechanisms,+signaling,+and+translation.">Wound repair and regeneration: mechanisms, signaling, and translation.</a> Science Translation Medicine. 6, 265-266 (2014).</li><li>Aryza, M. J., Baryza, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Vancouver+Scar+Scale:+an+administration+tool+and+its+interrater+reliability.">The Vancouver Scar Scale: an administration tool and its interrater reliability.</a> The Journal of Burn &amp; Rehabilitation. 16, 535-538 (1995).</li><li>Bystrom, A., Claesson, R., Sundqvist, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+antibacterial+effect+of+camphorated+paramonochlorophenol,+camphorated+phenol+and+calcium+hydroxide+in+the+treatment+of+infected+root+canals.">The antibacterial effect of camphorated paramonochlorophenol, camphorated phenol and calcium hydroxide in the treatment of infected root canals.</a> Endodontics &amp; Dental Traumatology. 1, 170-175 (1985).</li><li>Reig, A., Tejerina, C., Codina, J., Hidalgo, J., Mirabet, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Application+of+a+new+cicatrization+dressing+in+treating+second-degree+burns+and+donor+sites.">Application of a new cicatrization dressing in treating second-degree burns and donor sites.</a> Annals of Burn and Fire Disasters. 4, 174 (1991).</li><li>Hindy, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparative+study+between+sodium+carboxymethyl-cellulose+silver,+moist+exposed+burn+ointment,+and+saline-soaked+dressing+for+treatment+of+facial+burns.">Comparative study between sodium carboxymethyl-cellulose silver, moist exposed burn ointment, and saline-soaked dressing for treatment of facial burns.</a> Annals of Burn and Fire Disasters. 22, 131-137 (2009).</li><li>Galiano, R. 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=Topical+vascular+endothelial+growth+factor+accelerates+diabetic+wound+healing+through+increased+angiogenesis+and+by+mobilizing+and+recruiting+bone+marrow-derived+cells.">Topical vascular endothelial growth factor accelerates diabetic wound healing through increased angiogenesis and by mobilizing and recruiting bone marrow-derived cells.</a> The American Journal of Pathology. 164, 1935-1947 (2004).</li><li>Thangarajah, 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=The+molecular+basis+for+impaired+hypoxia-induced+VEGF+expression+in+diabetic+tissues.">The molecular basis for impaired hypoxia-induced VEGF expression in diabetic tissues.</a> Proceedings of the National Academy of Sciences of the United States of America. , 13505-13510 (2009).</li></ol>

The present study established a swine model of severe burn injury and examined the model using a CAPS-containing dressing. Our results suggest that this swine model can be used for monitoring the clinical performance of experimental dressings, including antibacterial property. Wound healing rate, wound closure, and antibacterial activity were also analyzed using VSS, H&#38;E staining, and antibacterial test. The use of animal burn models has been developed as a valuable tool to review the pathophysiology of burn injury. ...

A burn injury initiates the inflammatory process and induces complex pathological effects, which influence numerous body functions immediately after an accident, resulting in negative impact on patients&#39; quality of life. Impaired wound healing causes significant morbidity and mortality among patients with diabetes mellitus1,2. Most patients with burn injuries experience pain during burn wound debridement, which is known as an excruciating process despite the use of powerful opioid analgesics3.
In contrast to other mammals, swine share several anatomic and physiologic characteristics with humans regarding the process of epithelialization, cellular proliferation, and angiogenesis. This makes swine a potentially better model for certain procedures and studies, and they are often used in subsequent studies that demonstrated promising results in mice. These features have led to the increasing use of swine as a major species in preclinical testing. Recently, a rapid increase in biomedical research with respect to cardiovascular, urinary, integumentary, and digestive systems has been observed4,5,6. This study aims to demonstrate a swine model of severe burn injury that eliminates wound contraction and provides a closer approximation of the human wound healing processes and the formation of new tissue. Six burn wounds were created symmetrically on the dorsum, three on each side of the spine of the swine. Next,anexperimental dressing was examined in a swine model of severe burn injury, which can be adapted to replicate human wound healing (Figure 1). The wounds were covered with a clinical dressing, which is composed of four layers: an inner contact layer of experimental materials, an inner intermediate layer of waterproof film, an outer intermediate layer of gauze, and an outer layer of adhesive plaster. A waterproof film keeps the wound environment moist while preventing bacterial infection and allowing gases to permeate the dressing. The outer intermediate layer of gauze was applied on the waterproof films and secured by an outer layer of adhesive plaster. At the completion of experiments, wound closure, wound area, and Vancouver Scar Scale (VSS) score were examined. The samples of skin resected from each animal post-sacrifice were histologically prepared and stained using hematoxylin and eosin (HE) staining. Antibacterial activity of each dressing in the context of wound healing was also examined in this model. Our previous study has demonstrated wound-healing performance in rat and swine model using a minimally invasive surgical technique7. Since there were six burn wounds on the dorsum within each swine, each experimental dressing was tested and evaluated in all positions to minimize bias related to wound healing process in different spots on the swine dorsum. Therefore, the swine model of severe burn injury established in this study provides a new approach for the evaluation of clinical dressings and facilitates the development of a novel treatment for burn injury. This study provides crucial tools to uncover the pathophysiology of burn wound healing.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr >
			<td>Sedation:</td>
			<td></td>
			<td></td>
			<td></td>	
	</tr>
		<tr >
			<td >Ketamine</td>
			<td >Merial</td>
			<td>2528 ESP</td>
			<td>10 mL vial</td>
			<td ></td>
		</tr>
		<tr >
			<td >Azaperone</td>
			<td >China chemical &#38; pharmaceutical</td>
			<td>47W406</td>
			<td>100 mL vial</td>
			<td ></td>
		</tr>
		<tr >
			<td >Atropine&#160;</td>
			<td >Oriental chemical works</td>
			<td>IN120802</td>
			<td>1 mL vial</td>
			<td ></td>
		</tr>
		<tr >
			<td>Anesthetic:</td>
			<td></td>
			<td></td>
			<td></td>	
	</tr>
		<tr >
			<td >Tiletamine+Zolazepam</td>
			<td >Virbac</td>
			<td>BC91</td>
			<td >5 mL vial</td>
			<td ></td>
		</tr>
		<tr >
			<td >Isoflurane</td>
			<td >Baxter</td>
			<td>N002A225</td>
			<td >100 mL vial</td>
			<td ></td>
		</tr>
		<tr >
			<td>Surgery:</td>
			<td></td>
			<td></td>
			<td></td>
			</tr>
		<tr >
			<td >Hair clippers</td>
			<td >Moser</td>
			<td>-</td>
			<td >-</td>
			<td ></td>
		</tr>
		<tr >
			<td >Povidone iodine scrub solution</td>
			<td >Ever star</td>
			<td>HA161202</td>
			<td >4 L barrel</td>
			<td ></td>
		</tr>
		<tr >
			<td >Modified iron</td>
			<td >-</td>
			<td>-</td>
			<td >-</td>
			<td ></td>
		</tr>
		<tr >
			<td >Electronic thermometer</td>
			<td >Dogger</td>
			<td>A9SA-ST9215C</td>
			<td >- 50~300&#8451;</td>
			<td ></td>
		</tr>
		<tr >
			<td >0.9% saline solution</td>
			<td >CHI SHENG</td>
			<td>KC130</td>
			<td >500 mL vial</td>
			<td ></td>
		</tr>
		<tr >
			<td >Gauze</td>
			<td >China Surgical Dressings Center</td>
			<td>MO15900080</td>
			<td >10 x10 cm</td>
			<td ></td>
		</tr>
		<tr >
			<td >CAPS</td>
			<td >CoreLeader Biotech Co., Ltd, Taipei, Taiwan</td>
			<td>-</td>
			<td >-</td>
			<td ></td>
		</tr>
		<tr >
			<td >Paper tape</td>
			<td >3M</td>
			<td>NDC-8333-1530-01</td>
			<td >2.5 cm x 9.1m</td>
			<td ></td>
		</tr>
		<tr >
			<td >Waterproof film</td>
			<td >3M</td>
			<td>NDC-8333-1600-40</td>
			<td >10 cm x 10 m</td>
			<td ></td>
		</tr>
		<tr >
			<td >Adhesive plaster</td>
			<td >Young chemical</td>
			<td>BH1426015</td>
			<td >10 cm x 10 m</td>
			<td ></td>
		</tr>
		<tr >
			<td>Dissection:</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr >
			<td >Pair of standard sharp/blunt straight scissors (14 cm)</td>
			<td >Shinetec instruments</td>
			<td>ST-S114</td>
			<td >-</td>
			<td ></td>
		</tr>
		<tr >
			<td >Halstead-Mosquito (12.5 cm)</td>
			<td >Shinetec instruments</td>
			<td>ST-H012</td>
			<td >-</td>
			<td ></td>
		</tr>
		<tr >
			<td >Handle(# 4)</td>
			<td >Shinetec instruments</td>
			<td>ST-H004</td>
			<td >-</td>
			<td ></td>
		</tr>
		<tr >
			<td >Surgical Blade(#21)</td>
			<td >Shinetec instruments</td>
			<td>ST-B021</td>
			<td >-</td>
			<td ></td>
		</tr>
		<tr >
			<td>Post-Fixation &#38; Storage:</td>
		</tr>
		<tr >
			<td >50 ml Plastic centrifuge tube&#160;</td>
			<td >Falcon</td>
			<td>352070</td>
			<td >-</td>
			<td ></td>
		</tr>
		<tr >
			<td >10% neutral buffered formalin</td>
			<td >Leica</td>
			<td>3800604EG</td>
			<td >-</td>
			<td ></td>
		</tr>
		<tr >
			<td>Bacterial Growth Experiments&#160;</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr >
			<td >Blood agar plate (BAP) (TSA with 5% sheep blood)&#160;</td>
			<td >CMP</td>
			<td>-</td>
			<td >90 mm Mono</td>
			<td></td>
		</tr>
	</tbody>
</table>

severe burn injury in a swine model for clinical dressing assessment

Wound healing is a dynamic repair process and is the most complex biological process in human life. In response to burn injury, alterations in biological pathways impair the inflammation response, resulting in delayed wound healing. Impaired wound healing frequently occurs in patients with diabetes leading to unfavorable outcomes such as amputation. Hence, dressings having beneficial effect in promoting burn wound repair are needed. However, studies on burn wound treatment are limited due to lack of proper animal models. Our previous study demonstrated wound-healing performance in rat and swine models using a minimally invasive surgical technique. This study aimed to demonstrate a swine model of severe burn injury that eliminates wound contraction and more closely approximates the human processes of re-epithelialization and new tissue formation. This protocol provides a detailed procedure for creating consistent burn wounds and examining the wound-healing performance under the treatment of an experimental dressing in a swine model. Six burn wounds were created symmetrically on the dorsum, which were covered with a clinical dressing composed of four layers: an inner contact layer of experimental materials, an inner intermediate layer of waterproof film, an outer intermediate layer of gauze, and an outer layer of adhesive plaster. Upon the completion of experiments, wound closure, wound area, and Vancouver Scar Scale score were examined. The samples of skin resected from each animal post-sacrifice were histologically prepared and stained using hematoxylin and eosin staining. Antibacterial activity of each dressing in the context of wound healing was also examined. The application of the clinical dressing to the wounds in swine model mimics the biological processes of human wound healing with respect to the processes of epithelialization, cellular proliferation, and angiogenesis. Therefore, this swine model provides an easy-to-learn, cost-effective, and robust method to assess the effect of clinical dressings in severe burn injury.

Burn duration of 30 seconds by hot iron resulted in wounds that were circular with a well-defined margin and uniformly pale with a rim of erythema (Figure 1D). Within each animal, there were six burn wounds on the dorsum. The arrangement of burn wounds was depicted in Figure 1K. Burn wounds were completely covered with CAPS-containing dressing and used to evaluate the depth of scar formation on post-burn days 0, 7, 21, and 42 and...

Watch this Scientific Journal Video about Severe Burn Injury in a Swine Model for Clinical Dressing Assessment at JoVE.com

Severe Burn Injury in a Swine Model for Clinical Dressing Assessment

To closely mimic the mode of burn injuries requires the interplay between clinical observation and studies in animal models. In this study, a swine model of severe burn injury was established to assess an experimental dressing in physiological and pathophysiological settings.

Wound healing is a dynamic repair process and is the most complex biological process in human life. In response to burn injury, alterations in biological ...

This method can help answer key questions in the burn injury field about warfare wound handling or how to treat burn wounds after fire accident. The main advantage of this swine burn injury model is the degree of similarity between the anatomical and the physiological structure of pig and human skin tissue. Though this method can provide insight into the effects of calcium alginate polysaccharide dressings on burn wound healing, it can also be applied to studies of burn management.Before delivering the burn, shave and moisture an approximately 25-centimeter-wide area of skin from the vertebral column all the way to the axilla on both sides of the spine of an anesthetized adult pig. Then, scrub the exposed skin with povidone-iodine for approximately five minutes. Use wet sterile gauze to remove the povidone-iodine soap, and sterilize the clean skin with povidone-iodine lotion.And use a surgical marking pen to demarcate the center of six burn wound locations on the dorsum of the animal. Then, cover the animal with sterile surgical drapes, taking care that the distance between each area is at least greater than the radius of the area. When all of the areas have been marked, fill a modified soldering iron equipped with an approximately nine square centimeter flat area with 50 milliliters of glycerin, and insert an electronic thermometer into the iron to monitor the temperature.After heating the iron to 137 to 139 degrees Celsius on a hot plate, gently press the iron onto each marked area for 30 seconds per area to create six uniform burn wounds. When the heated iron touches the skin, the heat will immediately dissipate across the surface of burnt area, so be sure to preheat the iron and the glycerin for at least 10 minutes before applying the burns. Then, wash the wounds with 0.9%saline solution, and measure and record the wound dimensions by photomicrography.When all the wounds have been measured, apply the dressings directly onto each wound, followed by the application of a waterproof film over the inner dressing layer to serve as a barrier against bacterial penetration. Then, tape a 5-centimeter-thick piece of gauze over each wound to serve as the mid-layer of the dressing, and secure the gauze with an outer layer of adhesive plaster, extending the plaster to the torso to avoid displacement of the dressing. Change the clinical dressings every two days for the first 10 days, then twice a week until day 42, cleaning and measuring the wounds according to the Vancouver Scar Scale before each dressing reapplication.Swab the wound for antibacterial testing on post-burn days zero, seven, 21, and 42, and place the swabs in 100 milliliters of 0.9%sterile saline solution. Gently vortex the swabs to obtain a homogenous suspension, and serially dilute the resulting cell solution. Then, plate 100 microliters of each dilution in selective or nonselective medium, and incubate the wound culture under aerobic conditions at 37 degrees Celsius for 24 to 72 hours.At the end of the incubation, plate 10-microliter aliquots from each dilution culture in triplicate onto blood agar plates supplemented with 5%sheep blood for overnight culture at 37 degrees Celsius. The next morning, use a marker and a small ruler to divide the bottom of each dish into four equal quadrants, and determine the number of colony-forming units in each quadrant under a dissecting microscope. In this representative experiment, burn wounds re-epithelialization was evaluated by gross inspection on post-burn day 42.A significant reduction in wound area was observed compared to day zero. The healing rate was defined as the greatest average wound margin distance from the wound center divided by the time to complete wound closure, demonstrating over 73%wound closure on post-burn day 42. The Vancouver scar scores peaked on post-burn day 21 and decreased to below the initial wound size by post-burn day 42.Histologic examination of skin samples harvested on day 42 confirmed that full-thickness burns were achieved and that the wounds appeared to be fully healed. Necrosis resulting from burns could be observed in the epidermis, dermis, and dermal components of the wound without significantly affecting the underlying muscle. The thickness beneath the experimental dressing was 5.4 millimeters, and dermal sloughing and lymphocytic infiltration were observed.Bacterial cultures of wound swabs collected on post-burn days zero, seven, 21, and 42 demonstrated a slight increase in colony-forming units from days zero to 21 that were significantly increased on day 42, confirming that this swine model of severe burn injury can be used for monitoring the clinical performance of experimental dressings. While attempting this procedure, it's important to remember to know how to handle the animal and then to properly monitor the animal's vital sign during the evental period. Following this procedure, other methods like bacterial growth experiments can be performed to answer additional questions about how natural polysaccharide materials work in cases of severe burn injury.After its development, this technique paved the way for researchers in the field of burn wound healing to explore the effects of natural calcium alginate polysaccharide dressings in human skin healing. Don't forget that working with heated iron and glycerine can be extremely hazardous and that precautions such as functioning equipment should always be taken while performing the procedure.

severe-burn-injury-in-a-swine-model-for-clinical-dressing-assessment

Research

JoVE Journal

Medicine

A Swine Model of Neonatal Asphyxia

Annually more than 1 million neonates die worldwide as related to asphyxia. Asphyxiated neonates commonly have multi-organ failure including hypotension, perfusion deficit, hypoxic-ischemic encephalopathy, pulmonary hypertension, vasculopathic enterocolitis, renal failure and thrombo-embolic complications. Animal models are developed to help us understand the patho-physiology and pharmacology of neonatal asphyxia. In comparison to rodents and newborn lambs, the newborn piglet has been proven to be a valuable model. The newborn piglet has several advantages including similar development as that of 36-38 weeks human fetus with comparable body systems, large body size (&tilde;1.5-2 kg at birth) that allows the instrumentation and monitoring of the animal and controls the confounding variables of hypoxia and hemodynamic derangements.
We here describe an experimental protocol to simulate neonatal asphyxia and allow us to examine the systemic and regional hemodynamic changes during the asphyxiating and reoxygenation process as well as the respective effects of interventions. Further, the model has the advantage of studying multi-organ failure or dysfunction simultaneously and the interaction with various body systems. The experimental model is a non-survival procedure that involves the surgical instrumentation of newborn piglets (1-3 day-old and 1.5-2.5 kg weight, mixed breed) to allow the establishment of mechanical ventilation, vascular (arterial and central venous) access and the placement of catheters and flow probes (Transonic Inc.) for the continuously monitoring of intra-vascular pressure and blood flow across different arteries including main pulmonary, common carotid, superior mesenteric and left renal arteries. Using these surgically instrumented piglets, after stabilization for 30-60 minutes as defined by Z&lt;10% variation in hemodynamic parameters and normal blood gases, we commence an experimental protocol of severe hypoxemia which is induced via normocapnic alveolar hypoxia. The piglet is ventilated with 10-15% oxygen by increasing the inhaled concentration of nitrogen gas for 2h, aiming for arterial oxygen saturations of 30-40%. This degree of hypoxemia will produce clinical asphyxia with severe metabolic acidosis, systemic hypotension and cardiogenic shock with hypoperfusion to vital organs. The hypoxia is followed by reoxygenation with 100% oxygen for 0.5h and then 21% oxygen for 3.5h. Pharmacologic interventions can be introduced in due course and their effects investigated in a blinded, block-randomized fashion.

Large animal models have good translational values in the examination of physiology and pharmacology of neonatal asphyxia. Using newborn piglets, we develop an experimental protocol to simulate neonatal asphyxia which has advantages of studying the systemic and regional hemodynamics, oxygen transport with biochemical and pathologic pathways and correlations.

Annually more than 1 million neonates die worldwide as related to asphyxia. Asphyxiated neonates commonly have multi-organ failure including hypotension, ...

A Contusion Model of Severe Spinal Cord Injury in Rats

The translational potential of novel treatments should be investigated in severe spinal cord injury (SCI) contusion models. A detailed methodology is described to obtain a consistent model of severe SCI. Use of a stereotactic frame and computer controlled impactor allows for creation of reproducible injury. Hypothermia and urinary tract infection pose significant challenges in the post-operative period. Careful monitoring of animals with daily weight recording and bladder expression allows for early detection of post-operative complications. The functional results of this contusion model are equivalent to transection models. The contusion model can be utilized to evaluate the efficacy of both neuroprotective and neuroregenerative approaches.

A contusion model of severe spinal cord injury is described. Detailed pre-operative, operative and post-operative steps are described to obtain a consistent model.

The translational potential of novel treatments should be investigated in severe spinal cord injury (SCI) contusion models. A detailed methodology is ...

An Alkali-burn Injury Model of Corneal Neovascularization in the Mouse

Under normal conditions, the cornea is avascular, and this transparency is essential for maintaining good visual acuity. Neovascularization (NV) of the cornea, which can be caused by trauma, keratoplasty or infectious disease, breaks down the so called &lsquo;angiogenic privilege' of the cornea and forms the basis of multiple visual pathologies that may even lead to blindness. Although there are several treatment options available, the fundamental medical need presented by corneal neovascular pathologies remains unmet. In order to develop safe, effective, and targeted therapies, a reliable model of corneal NV and pharmacological intervention is required. Here, we describe an alkali-burn injury corneal neovascularization model in the mouse. This protocol provides a method for the application of a controlled alkali-burn injury to the cornea, administration of a pharmacological compound of interest, and visualization of the result. This method could prove instrumental for studying the mechanisms and opportunities for intervention in corneal NV and other neovascular disorders.

Neovascularization (NV) of the cornea can complicate multiple visual pathologies. Utilizing a controlled, alkali-burn injury model, a quantifiable level of corneal NV can be produced for mechanistic study of corneal NV and evaluation of potential therapies for neovascular disorders.

Under normal conditions, the cornea is avascular, and this transparency is essential for maintaining good visual acuity. Neovascularization (NV) of the ...

Clinical Assessment of Spatiotemporal Gait Parameters in Patients and Older Adults

Spatial and temporal characteristics of human walking are frequently evaluated to identify possible gait impairments, mainly in orthopedic and neurological patients1-4, but also in healthy older adults5,6. The quantitative gait analysis described in this protocol is performed with a recently-introduced photoelectric system (see&#160;Materials table) which has the potential to be used in the clinic because it is portable, easy to set up (no subject preparation is required before a test), and does not require maintenance and sensor calibration. The photoelectric system consists of series of high-density floor-based photoelectric cells with light-emitting and light-receiving diodes that are placed parallel to each other to create a corridor, and are oriented perpendicular to the line of progression7. The system simply detects interruptions in light signal, for instance due to the presence of feet within the recording area. Temporal gait parameters and 1D spatial coordinates of consecutive steps are subsequently calculated to provide common gait parameters such as step length, single limb support and walking velocity8, whose validity against a criterion instrument has recently been demonstrated7,9. The measurement procedures are very straightforward; a single patient can be tested in less than 5 min&#160;and a comprehensive report can be generated in less than 1&#160;min.

This protocol is used to evaluate spatial and temporal gait variables of neurological/orthopedic patients and older persons by means of a recently-introduced floor-based photocell system.

Spatial and temporal characteristics of human walking are frequently evaluated to identify possible gait impairments, mainly in orthopedic and ...

A Repetitive Concussive Head Injury Model in Mice

Despite the concussion/ mild traumatic brain injury (mTBI) being the most frequent occurrence of traumatic brain injury, there is still a lack of knowledge on the injury and its effects. To develop a better understanding of concussions, animals are often used because they provide a controlled, rigorous, and efficient model. Studies have adapted traditional animal models to perform mTBI to stimulate mild injury severity by changing the injury parameters. These models have been used because they can produce morphologically similar brain injuries to the clinical condition and provide a spectrum of injury severities. However, they are limited in their ability to present the identical features of injuries in patients. Using a traditional impact system, a repetitive concussive injury (rCHI) model can induce mild to moderate human-like concussion. The injury degree can be determined by measuring the period of loss of consciousness (LOC) with a sign of a transient termination of breathing. The rCHI model is beneficial to use for its accuracy and simplicity in determining mTBI effects and potential treatments.

Concussion presents the most common type of traumatic brain injury. Therefore, a repetitive concussive animal model, which replicates the important features of an injury in patients, may provide a means to study concussion in a rigorous, controlled, and efficient manner.

Despite the concussion/ mild traumatic brain injury (mTBI) being the most frequent occurrence of traumatic brain injury, there is still a lack of ...

Induction of Accelerated Atherosclerosis in Mice: The "Wire-Injury" Model

Atherosclerosis is a proliferative fibro-inflammatory disease developing in the arterial wall, inducing a deficient blood flow or a lack of blood flow. Moreover, by rupture of the defective vascular wall, atherosclerosis induces occlusive thrombus formation, which represents the main cause of myocardial infarction or stroke and the most frequent cause of death. Despite the advances in the cardiovascular field, many questions remain unanswered, and additional basic research is essential to improve our understanding of the molecular mechanisms during atherosclerosis and its effects. Due to limited clinical studies, there is a need for representative animal models recreating atherosclerotic conditions such as neointima formation after stent implantation, balloon angioplasty, or endarterectomy. Since the mouse presents many advantages and is the most frequently used model for studying molecular processes, the current study proposes an invasive procedure of endothelial denudation, also known as the wire-injury model, which is representative of the human condition of neointima formation in arteries after revascularization procedures.

Induction of Accelerated Atherosclerosis in Mice: The &quot;Wire-Injury&quot; Model

This study describes an invasive procedure for the induction of accelerated atherosclerosis in mice. In comparison to other methods using electric- or cryo-induced injury, mechanical-induced injury mimics the human condition of restenosis after revascularization therapies and is ideal for the study of the molecular mechanisms involved.

Atherosclerosis is a proliferative fibro-inflammatory disease developing in the arterial wall, inducing a deficient blood flow or a lack of blood flow. ...

Tachycardia-Induced Cardiomyopathy As a Chronic Heart Failure Model in Swine

A stable and reliable model of chronic heart failure is required for many experiments to understand hemodynamics or to test effects of new treatment methods. Here, we present such a model by tachycardia-induced cardiomyopathy, which can be produced by rapid cardiac pacing in swine.
A single pacing lead is introduced transvenously into fully anaesthetized healthy swine, to the apex of the right ventricle, and fixated. Its other end is then tunneled dorsally to the paravertebral region. There, it is connected to an in-house modified heart pacemaker unit that is then implanted in a subcutaneous pocket. 
After 4 - 8 weeks of rapid ventricular pacing at rates of 200 - 240 beats/min, physical examination revealed signs of severe heart failure - tachypnea, spontaneous sinus tachycardia, and fatigue. Echocardiography and X-ray showed dilation of all heart chambers, effusions, and severe systolic dysfunction. These findings correspond well to decompensated dilated cardiomyopathy and are also preserved after the cessation of pacing.
This model of tachycardia-induced cardiomyopathy can be used for studying the pathophysiology of progressive chronic heart failure, especially hemodynamic changes caused by new treatment modalities like mechanical circulatory supports. This methodology is easy to perform and the results are robust and reproducible.

Here, we present a protocol to produce tachycardia-induced cardiomyopathy in swine. This model represents a potent way to study the hemodynamics of progressive chronic heart failure and the effects of applied treatment.

A stable and reliable model of chronic heart failure is required for many experiments to understand hemodynamics or to test effects of new treatment ...

Semi-quantitative Assessment Using [18F]FDG Tracer in Patients with Severe Brain Injury

Patients with severe traumatic brain injury (sTBI) have difficulty knowing whether they are accurately expressing their thoughts and emotions because of disorders of consciousness, disrupted higher brain function, and verbal disturbances. As a consequence of an insufficient ability to communicate, objective evaluations are needed from family members, medical staff, and caregivers. One such evaluation is the assessment of functioning brain areas. Recently, multimodal brain imaging has been used to explore the function of damaged brain areas. [18F]-fluorodeoxyglucose positron emission tomography-computed tomography ([18F]FDG-PET/CT) is a successful tool for examining brain function. However, the assessment of brain glucose metabolism based on [18F]FDG-PET/CT is not standardized and depends on several varying parameters, as well as the patient&#39;s condition. Here, we describe a series of semiquantitative assessment protocols for a region-of-interest (ROI) image analysis using self-produced [18F]FDG tracers in patients with sTBI. The protocol focuses on screening the participants, preparing the [18F]FDG tracer in the hot lab, scheduling the acquisition of [18F]FDG-PET/CT brain images, and measuring glucose metabolism using the ROI analysis from a targeted brain area.

Semi-quantitative Assessment Using [18F]FDG Tracer in Patients with Severe Brain Injury

[18F]-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography is useful for studying glucose metabolism related to brain function. Here, we present a protocol for an [18F]FDG tracer set-up and semiquantitative assessment of the region-of-interest analysis for targeted brain areas associated with clinical manifestations in patients with severe traumatic brain injury.

Patients with severe traumatic brain injury (sTBI) have difficulty knowing whether they are accurately expressing their thoughts and emotions because of ...

Establishment of a Severe Dry Eye Model Using Complete Dacryoadenectomy in Rabbits

Dry eye disease (DED) is a complex disease with multiple etiologies and variable symptoms, having ocular surface inflammation as its key pathophysiologic step. Despite advances in our understanding of DED, significant knowledge gaps remain. Advances are limited in part due to the lack of informative animal models. The authors recently reported on a method of DED induced by injecting all orbital lacrimal gland (LG) tissues with the lectin concanavalin A. Here, we report a novel model of aqueous-deficient DED based on the surgical resection of all orbital LG (dacryoadenectomy) tissues. Both methods use rabbits because of their similarity to human eyes in terms of the size and structure of the ocular surface. One week after removal of the nictitating membrane, the orbital superior LG was surgically removed under anesthesia, followed by removal of the palpebral superior LG, and finally removal of the inferior LG. Dacryoadenectomy induced severe DED, evidenced by a marked reduction in the tear break up time test and the Schirmer&#39;s tear test, and significantly increased tear osmolarity and rose bengal staining. Dacryoadenectomy-induced DED lasted at least eight weeks. There were no complications and animals tolerated the procedure well. The technique can be mastered relatively easily by those with adequate surgical experience and appreciation of the relevant rabbit anatomy. Since this model recapitulates the features of human aqueous-deficient DED, it is suitable for studies of ocular surface homeostasis, DED, and candidate therapeutics.

A novel approach is presented to induce chronic dry eye disease in rabbits by surgically removing all orbital lacrimal glands. This method, distinct from those previously reported, produces a stable, reproducible model of aqueous deficient dry eye well suited to study tear physiology and pathophysiology and ocular therapeutics.

Dry eye disease (DED) is a complex disease with multiple etiologies and variable symptoms, having ocular surface inflammation as its key pathophysiologic ...

A Pre-clinical Rat Model for the Study of Ischemia-reperfusion Injury in Reconstructive Microsurgery

Ischemia-reperfusion injury is the main cause of flap failure in reconstructive microsurgery. The rat is the preferred preclinical animal model in many areas of biomedical research due to its cost-effectiveness and its translation to humans. This protocol describes a method to create a preclinical free skin flap model in rats with ischemia-reperfusion injury. The described 3 cm x 6 cm rat free skin flap model is easily obtained after the placement of several vascular ligatures and the section of the vascular pedicle. Then, 8 h after the ischemic insult and completion of the microsurgical anastomosis, the free skin flap develops the tissue damage. These ischemia-reperfusion injury-related damages can be studied in this model, making it a suitable model for evaluating therapeutic agents to address this pathophysiological process. Furthermore, two main monitoring techniques are described in the protocol for the assessment of this animal model: transit-time ultrasound technology and laser speckle contrast analysis.

Here, we describe a pre-clinical animal model for studying the pathophysiology of ischemia-reperfusion injury in reconstructive microsurgery. This free skin flap model based on the superficial caudal epigastric vessels in the rat may also allow for the evaluation of different therapies and compounds to counteract ischemia-reperfusion injury-related damage.

Ischemia-reperfusion injury is the main cause of flap failure in reconstructive microsurgery. The rat is the preferred preclinical animal model in many ...