A pig model of wound healing was developed by excision of 2 cm diameter full thickness skin in young Yorkshire pigs. Theconsistency of this animal model for the molecular analysis of wound healing was assessed with quantification of total RNA yieldand comparison of mRNA levels for type III collagen from skin samples derived from different locations on the pigs. The pattern ofchange at the molecular and cellular level during healing in this animal model was defined, as well as the bacteriological profile.mRNA expression for relevant genes was assessed by semiquantitative reverse transcription polymerase chain reaction (RT-PCR)using porcine specific primer sets and RNA isolated from normal skin and samples at various times post-wounding. Analysis ofcellular change was assessed by DNA quantification and apoptotic cells in tissue sections. Quantitative bacteriology was performedusing standard techniques and selective plating techniques. The results demonstrated that wound re-epithelialization in this animalmodel took an average of 20 days. The results also show that the observed changes in the pattern of RNA and DNA content of thescar tissues were consistent with cell loss due to apoptosis in this model. The mRNA levels for tumor necrosis factor.4z (TNF-ot),connective tissue growth factor (CTGF), insulin-like growth factor-2 (IGF-2), and decorin, were significantly elevated at specifictimes after wounding, but mRNA levels for the transcription factors (c-los and c-jun) were siginificantly depressed. These studiessuggest that skin wound healing is a dynamic and complex process. The results of the bacteriology study indicated that the totalbacterial count in this animal model reached 109 CFU/gram, with the highest value at day 7 post-wounding. Pseudomonasaeruginosa and Staphylocococci aureus were the most common bacteria detected in this model. Further definition of this modelshould identify unique points in the healing process. Such information could lead to the development of therapeutic interventions toimprove skin wound healing.