Effect of activated protein C in second intention healing of equine distal limb wounds: a preliminary study

• Published in: Australian veterinary journal Vol. 93; no. 10; pp. 361 - 366
• Main Authors: Bischofberger, AS, Tsang, AS, Horadagoda, N, Dart, CM, Perkins, NR, Jeffcott, LB, Jackson, CJ, Dart, AJ
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01-10-2015; Wiley Subscription Services, Inc
• Subjects: activated protein C; Animals; Anti-Bacterial Agents - pharmacology; Anti-Infective Agents - pharmacology; bacitracin; Bacitracin - pharmacology; Drug Combinations; Gels; Honey; Horses; Lower Extremity - injuries; Lower Extremity - physiopathology; Male; Manuka honey gel; neomycin; Neomycin - pharmacology; petrolatum; Photography; polymixin B ointment; Polymyxin B - pharmacology; Protein C - pharmacology; Random Allocation; Recombinant Proteins - pharmacology; Skin - drug effects; Skin - injuries; wound healing; Wound Healing - drug effects; Wound Healing - physiology; petrolatum; polymixin B ointment; wound healing; Manuka honey gel; neomycin; bacitracin; activated protein C; horses
• ISSN: 0005-0423; 1751-0813
• DOI: 10.1111/avj.12363

Objective
To investigate the effect of activated protein C (APC) on second intention healing of distal limb wounds in horses.
Methods
In this experimental study of eight Standardbred geldings, six full‐thickness skin wounds (2 × 1.5 cm) were created on one metacarpus (biopsy limb) and five similar wounds were created on the contralateral metacarpus (photographed limb). Three wounds on the biopsy limb were treated topically with 190 µg APC on days 1, 3, 6 and 9, while the remaining three wounds were untreated (control). One treated and one control wound were biopsied on days 4, 7 and 11 for histopathology. Wounds on the photographed limb were treated with either 66% Manuka honey gel, a commercial antibiotic ointment (bacitracin–neomycin–polymixin B ointment; BNP) or petrolatum daily throughout healing, treated on days 1,3,6 and 9 with 190 µg APC or left untreated. These wounds were digitally photographed and the wound area measured on day 1, then weekly until day 49. Overall time to healing was recorded.
Results
There was no effect of APC on wound size, the rate of healing or the overall time to heal. However, compared with control wounds, histological scoring demonstrated enhanced epithelialisation (day 4) and angiogenesis (day 11). Wound healing variables for wounds treated with APC, Manuka honey gel and control wounds were not different and the variables for wounds treated with BNP and petrolatum demonstrated delayed healing.
Conclusion
The improvements in histological scores in APC‐treated wounds suggest further study into the effect of APC on second intention wound healing in horses is warranted.