Establishment of a Bama miniature pig burn model with different burn depths.

Background: The skin morphological characteristics of the Bama miniature pig are very similar to those of humans; thus, the Bama miniature pig is an ideal choice for establishing a skin burn model. Methods: In this study, 6 ordinary, male, Bama miniature pigs (weight: 23-28 kg and length: 71-75 cm) were used to establish burn models. A mixture of 1 mg of Ketamine and Sumianxin II was used for Bama miniature pigs anesthetizing, and 1 mg of Pentobarbital sodium was added as necessary. The different burn depths were made using a continuous pressure of 1 kg and contact times of 0 s, 10 s, 15 s, 20 s, 25 s, 30 s, 35 s, 40 s, and 45 s by the newly invented electronic burn instrument. The burned tissues were collected and examined with hematoxylin and eosin (H&E) and Masson staining. Results: Burning for 10-15 s caused a first-degree burn; the blood vessels in the superficial dermis were dilated and congested, and necrosis occurred above the basal layer of the epidermis. Burning for 20-25 s caused a superficial partial-thickness burn; the whole epidermal layer was necrotic, and the collagen fibers were slightly deformed. Burning for 30-35 s caused a deep partial-thickness burn; the whole epidermal layer and dermal layers were necrotic with leukocyte infiltration zones, and the collagen fibers were disordered, degenerated, and necrotized. Burning for 40-45 s caused a third-degree burn; the skin layers and adipose tissues were necrotic, and the thick blood vessels in the skin adipose tissues were full of disintegrated and agglutinated red blood cells. Conclusions: Stable burn depth models of Bama miniature pigs were constructed using a new and innovative electronic burn instrument. Our findings provide a basis for further research on the burn mechanism and evaluations of therapeutic drugs.