In the search for an effective animal model of hypertrophic burn scarring

Mitchell Nash1, Prof. Andrew Holland2,* ? pathologist Prof. John Harvey3

1 Burn Fellow Westmead Children’s Hospital Sydney, Westmead, NSW, 2145,
2 Prof. of Paediatric Surgery, Children’s Hospital Sydney, Westmead, NSW, 2145,
3 Head of Burns Unit, Children’s Hospital Sydney, Westmead, NSW, 2145,
Hypertrophic scarring (HTS) is characterised by the development of a thick red raised itchy scar. HTS is particularly common in children following a burn injury with an incidence of 20% in burns that heal under 21 days and over 90% when healing is delayed beyond 40 days. Recent laser therapy has shown some promise as an effective therapy (3), however, there are no randomised controlled trials and very little experimental evidence to support its use(4). In order to help develop and evaluate effective alternative treatments the search for an effective reproducible animal model for hypertrophic burns scars has been ongoing for more that 35 years (5).
The porcine model is well supported in the literature as the best available animal model for investigating human skin burns in terms of histological match, immunohistochemistry, scar formation, cost effectiveness and housing/experimental practicality (5-8). The Red Duroc pig strain was selected as the strain has been well validated by the Harborview Medical Centre group (9-12). We report a novel technique of using a skin expander underneath a contact thermal burn to create constant tension on the burn wound to develop reproducible HTS. This concept was extrapolated from a paper by Aarabi et al which concluded that “mechanical loading early in the proliferative phase of wound healing produces hypertrophic scars by inhibiting cellular apoptosis through an Akt-dependent mechanism”13. This was identified using an external frame to expand the wound

We will report the histological and immunochemistry findings of these expanded burn wound as compared to a control (non-expanded) burn. These experiments were conducted with ethical approval from Westmead Children’s Hospital.
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Key Words
Hypertrophic Scar

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