Comparative Transcriptome Analysis of Superficial and Deep Partial-Thickness Burn Wounds in Yorkshire vs Red Duroc Pigs

Hypertrophic scars are a common negative outcome of deep partial-thickness (DPT) burn wounds resulting in increased dermal thickness, wound area contracture, and inflammation of the affected area. The red Duroc and Yorkshire porcine breeds are common large animal models for studying dermal wounds due to their structural similarities to human skin; however, the porcine transcriptomic profiles of dermal burn wounds and healing process are not well known. In response, a longitudinal transcriptomic comparative study was conducted comparing red Duroc and Yorkshire superficial and DPT burn wounds to their respective control uninjured tissue. Using next-generation RNA sequencing, total RNAs were isolated from burn wound tissue harvested on 0, 3, 7, 15, 30, and 60 days postburn, and mRNA-seq and gene expression read counts were generated. Significant differentially expressed genes relative to uninjured tissue were defined, and active biological processes were determined using gene set enrichment analyses. Additionally, collagen deposition, α-smooth muscle actin (SMA) protein concentration, epidermal and dermal thickness measurements, and wound area changes in response to burn injury were characterized. Overall, the red Duroc pigs, in response to both burn wound types, elicited a more robust and prolonged inflammatory immune response, fibroblast migration, and proliferation, as well as heightened levels of extracellular matrix modulation relative to respective burn types in the Yorkshire pigs. Collectively, the red Duroc DPT burn wounds produce a greater degree of hypertrophic scar-like response compared with Yorkshire DPT burn wounds. These findings will facilitate future porcine burn studies down-selecting treatment targets and determining the effects of novel therapeutic strategies.