The pig as an experimental model for mid-dermal burns research.

This was a novel, prospective and interventional animal study designed to develop and evaluate a new infliction device for the experimental burn model. Four paired sets of contact burns measuring 36mm diameter were inflicted on the dorsum of an anesthetized pig using a stainless steel round bar heated up to 80-110°C. The bar was applied using a push-pull force gauge designed to control 1kgf mechanical force applied to the skin for a period of 20s. The left dorsum was used for macroscopic observation and the right dorsum was used for histopathological evaluation. A total of eight burns were covered with moist saline dressings and given daily treatments of xylocaine (lidocaine HCl) gel. This procedure was followed for a period of 24 days. Full-thickness biopsies were obtained for histologic analysis to determine the extent of injury. Statistical analysis showed a high correlation between the exposure temperature and histopathological assessment. The results found the depth of injury to the collagen (Seg1) correlated with the temperature (Ti) at which the burns was inflicted, Seg1=0.038Ti-2.57 (r=0.973, P<0.05). Also, the histological studies show a high correlation between the depth of collagen denaturation in wounds and the exposure temperature, Seg1=0.0268Ti-0.165 (r=0.991, P<0.05). This model is useful to assess more closely the therapeutic agents used for wound healing in experimental burn wounds.