Small Animal Surgery Resident University of Georgia, Florida
Evaluation of a Topically Applied Sildenafil Citrate Hydrogel and Its Influence on Wound Healing in Dogs. Sumner SM1, Wallace ML1, Mulder AT2, Delmotte SB1, Lindell H1, Duran SH3, Annaji M4, Dimick T4, Poudel I4, Babu RJ4. 1University of Georgia, College of Veterinary Medicine, Department of Small Animal Medicine and Surgery, Athens, GA; 2University of Georgia, College of Veterinary Medicine, Department of Pathology, Athens, GA; 3Auburn University, College of Veterinary Medicine, Department of Clinical Science, Auburn, AL; 4Auburn University, Harrison School of Pharmacy, Department of Drug Discovery and Development, Auburn, AL.
Sildenafil may benefit wound healing due to the release of nitric oxide, which potentiates clotting, scavenges free radicals, promotes angiogenesis, and has antimicrobial activity. We hypothesized that topical sildenafil hydrogel would accelerate wound healing in dogs compared to hydrogel alone or a nonadherent bandage. Four full-thickness excision wounds were created along the dorsum of six dogs. Each wound was treated with either a Telfa pad (C), hydrogel (G), 5% sildenafil hydrogel (5S), or 10% sildenafil hydrogel (10S). Sildenafil hydrogel concentrations were masked and randomized. Daily bandage changes were performed for wound care, treatment application, wound assessment, and image acquisition. Daily images were masked and randomized, and measurements acquired of total wound area, open wound area, and area of epithelialization. The time to first granulation tissue was significantly shorter for sildenafil treatment groups (2.8 ± 0.8 days (5S, 10S)) compared to control groups (5.2 ± 0.4 (C) and 6.3 ± 1.4 days (G)) (P = 0.039). Hydrogel alone had a 10%–14% lower contraction rate compared to C, 5S, and 10S. 5S wounds had a total wound area 0.7 ± 0.3 cm2 larger than 10S wounds (P = 0.04). No significant differences were present when C was compared to 5S or 10S in total wound area, contraction, or epithelialization. Limitations of this study include small sample size and surgically created wounds. This study found sildenafil promoted early granulation formation. Hydrogel delayed wound contraction and epithelialization, some of which sildenafil overcame. Topical sildenafil may be more efficacious in promoting wound healing with a different hydrogel formulation.