Various animal wound models have been introduced to imitate the wound healing mechanism of human. Rodents are good candidates for wound model, however, their healing occurs mainly by contraction, rather than epithelialization. There has been attempts to overcome this contraction by applying the external splint on a rodent wound healing model. These models, however, have problems regarding the assimilating ability to the dynamic animal movements and the robustness issues.
The authors attempted to produce a new animal wound model with internal splint made of shape memory alloys (SMAs), which would assimilate to the dynamic movement of animal soft tissues and provide robustness and reliability
First, we selected the most eligible SMA assimilating to the rat dorsal wound model. SMAs with different diameters of thickness was tested by intradermal weaving at the excisional wound periphery. Skin erosion, SMA resistance and healing condition was analyzed. After selecting the appropriate SMA for the model, internally splinted wound model was made and the wound healing conditions were inspected by wound analysis and histological analysis. Any unexpected events or unusual animal responses were recorded and analyzed.
On wound analysis, both primary and secondary wound contraction were significantly decreased in splinted rats compared to the unsplinted ones. No significant difference in the rate of epithelialization was observed. With the foregoing two results, the proportion of epithelialization in wound healing was significantly high in splinted rats when compared to unsplinted rats.
This is a novel model of wound healing in rats using SMA as internal splint to prevent the wound contraction, and thus effectively replicating human wound healing mechanism. Because this model does not have any exposed part around the excisional wound, cleaner, controlled wound healing study can be performed.