Effect of a silicone-containing dressing on exuberant granulation tissue formation and wound repair in horses.

This research investigates the impact of using a silicone dressing over traditional dressings on equine limb wound healing and specifically, the formation of excessive granulation tissue, also using histologic and immunohistochemical analysis techniques to observe microvascular and cellular differences between the wounds treated with two types of dressings.

Methodology

• Five horses were involved in the study, and each horse was given two identical wounds on each metacarpus, creating a total of ten wounds that were treated with a silicone dressing and ten wounds that were treated with a standard dressing.
• The scientists monitored wound size and tissue repair quality over time, keeping tabs on the number of times excess granulation tissue had to be removed (this is often an issue in equine healing, and is also known as ‘proud flesh’).
• In-depth tissue and cellular analysis were done on the healed wounds, including semiquantitative histologic examination, p53 immunohistochemical analysis, terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) to measure cell death (apoptosis), and electron microscopic examination to inspect the diameters of microvessels in the samples.

Results

• The silicone dressing proved to be superior to the traditional dressing in both preventing excess granulation tissue (proud flesh) and enhancing tissue quality.
• Interestingly, wounds dressed with the silicone product demonstrated a significantly greater number of obstructed microvessels. This is noteworthy as it is usually assumed that good blood circulation is critical in wound healing.
• The silicone dressing also influenced the expression of mutant p53, the protein responsible for controlling cell division and preventing tumor formation, which indirectly inhibits cell death. This may hint that the silicone dressing accelerates wound healing through manipulation of cell survival.
• Furthermore, even though the dressing affected expression of p53, this did not correlate with greater apoptosis rates when evaluated via TUNEL.

Conclusions

• Given its apparent superior performance, the silicone dressing may provide a more effective tool for wound management in horses, specifically in controlling the commonly problematic issue of excessive granulation tissue growth during healing.