Severe Burn Injury in a Swine Model for Clinical Dressing Assessment

Summary

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.

Abstract

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.

Introduction

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' quality of life. Impaired wound healing causes significant morbidity and mortality among patients with diabetes mellitus^1,2. 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....

Protocol

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

1. After arrival in the facility, house the animals solitarily but let them interact with each other.
2. Provide the animals ad libitum access to food and water.
3. Acclimate swine to human handling and transportation from the animal facility ....

Results

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.......

Discussion

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&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. .......

Materials

List of materials used in this article

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