Comparative evaluation of collagen and silicone foam dressings embedded with autologous PRP in equine wound healing

Introduction

In horses, wounds of the distal limbs commonly occur following traumatic incidents. Standard treatment protocols generally involve thorough wound debridement followed by the application of appropriate bandaging, often continued for several weeks or even months. In certain situations, the duration of healing becomes a major concern for horse owners, prompting veterinarians to adopt advanced wound management strategies to accelerate the healing process (Alford et al., 2012; Provost, 2012; Xian et al., 2015; Yamauchi et al., 2016) [1, 5, 10, 11] . Regenerative therapeutic approaches, including the use of extracellular matrix (ECM) components and autologous platelet-rich plasma (PRP), help establish a favorable microenvironment that supports rapid and effective wound repair. Collagen, a natural ECM component, facilitates cell adhesion, proliferation, and differentiation, thereby enhancing tissue regeneration. Commercially available collagen dressings in various forms such as sheets, powders, gels, and sponges have been shown to promote epithelialization during wound healing (Ruszczak, 2003) [7] . In contrast, silicone dressings are synthetic, non-adherent, and fully occlusive materials that aid wound healing while limiting the development of exuberant granulation tissue, a common complication in equine wounds (Ducharme-Desjarlais et al., 2005) [4] . The present study was designed to comparatively evaluate the wound healing efficacy of autologous PRP when combined with collagen and silicone dressings in the treatment of cutaneous wounds in horses.

Materials and Methods

The study was conducted on horses presented with cutaneous wounds to the Large Animal Surgical Outpatient Unit, Madras Veterinary College Teaching Hospital, Chennai, from 2017 to 2021. Twelve clinical cases were randomly divided into two groups (n = 6 each), wherein Group I received collagen extracellular matrix (ECM) dressing embedded with autologous platelet-rich plasma (PRP) and Group II received silicone ECM dressing embedded with autologous PRP. Autologous equine PRP was prepared using a double centrifugation method as described by Arguelles et al. (2005) [2] . In Group I, a wet collagen sheet (VILLICOL Type -I Collagen, manufacture by colognes is health care Pvt. Ltd,) layered with activated PRP gel was applied directly to the prepared wound surface and covered with a three-layer bandage consisting of a primary collagen-PRP dressing, a secondary cotton padding layer, and a tertiary protective layer. In Group II, activated PRP gel was spread over a silicone foam dressing (ALLEVYN Gentle Border®, Smith & Nephew) and applied to the wound using the same bandaging protocol. Dressings for both groups were performed on days 0, 5, 15, 30 and 45, with bandage changes every 3-4 days based on the extent of wound exudation and contamination.

Results and Discussion

In Groups I and II, six horses each with cutaneous wounds were treated using collagen and silicone extracellular matrix (ECM) dressings embedded with autologous platelet-rich plasma (PRP), respectively (Fig. 1 &2). Both treatment modalities were well tolerated, and the silicone foam dressing showed good biocompatibility with no observable adverse tissue reactions at days 0, 5, 15, and 45 following application. Dressing replacements were carried out at 3-4 day intervals based on wound size and the volume of exudate. The mean (± SE) percentage of wound healing observed in both groups at different post-treatment intervals is presented in Table 1, highlighting the comparative healing response between collagen-PRP and silicone-PRP dressings. The mean (± SE) percentage of total wound healing in Group I animals showed a consistent and progressive increase over the observation period, whereas Group II animals demonstrated comparatively lower healing percentages at corresponding time points. This resulted in a significantly higher overall wound healing response in equines treated with collagen dressing embedded with autologous platelet-rich plasma compared to those treated with silicone foam dressing combined with PRP. Statistical analysis revealed a significant difference between the two groups on day 15 (p≤ 0.05) and a highly significant difference on days 30 and 45 (p≤ 0.01).

In the present investigation, the collagen dressing was well tolerated, with no evidence of local tissue reaction, indicating good biocompatibility. These findings are consistent with previous reports by Swaim et al. (2000) [9] , You et al. (2017) [12] , Ramanathan et al. (2018) [6] , and Santhanam et al. (2020) [8] , who demonstrated the safety and effectiveness of collagenbased wound dressings. The positive response observed in this study may be attributed to the inherent properties of collagen, including low immunogenicity, reduced risk of infection, and high compatibility with host tissues, which collectively support cellular attachment and tissue regeneration. Similarly, in Group II, silicone foam dressing was found to be biocompatible and easy to apply for the management of equine cutaneous wounds. No adverse tissue reactions were observed during the treatment period, confirming its suitability for wound care. These results align with the findings of Desjarlais et al. (2005) [4] , who reported that silicone foam dressings promote wound healing while minimizing local tissue irritation in horses.

Conclusion

Based on this study, collagen dressing embedded with autologous platelet-rich plasma (PRP) significantly enhanced wound healing in horses compared to silicone foam-PRP dressing. Its application may reduce healing time, lower the risk of infection, and improve clinical outcomes in veterinary practice.

Acknowledgement

AcknowledgmentThe authors are grateful to the Dean, Madras Veterinary College, for providing the necessary facilities to carry out this work.

References

1. Alford CG, Caldwell FJ, Hanson R. Equine distal limb wounds: New and emerging treatments. Compendium: Continuing Education for Veterinarians. 2012;34(7):5-5.
2. Arguelles D, Carmona JU, Pastor J, Iborra A, Vinals L, Martinez P, et al. Evaluation of single and double centrifugation tube methods for concentrating equine platelets. Veterinary Science Research Journal. 2005;75(1):230-242.
3. DeJarlais BR, Scherz R, Snyder R, Wanka LJ. Relationship of coffee consumption and energy expenditure. Kinesiology Research. 2005;1(1):55-59.
4. Ducharme-Desjarlais M, Celeste CJ, Lepault E, Theoret CL. Effect of a silicone-containing dressing on exuberant granulation tissue formation and wound repair in horses. American Journal of Veterinary Research. 2005;66(7):1133-1139.
5. Provost PJ. Wound healing. In: Equine Surgery. 4th ed. St. Louis (MO): Elsevier Saunders; 2012. p.47-61.
6. Ramanathan G, Thyagarajan S, Sivagnanam UT. Accelerated wound healing and its promoting effects of biomimetic collagen matrices with siderophore-loaded gelatin microspheres in tissue engineering. Materials Science and Engineering C. 2018;93:455-464.
7. Ruszczak Z. Effect of collagen matrices on dermal wound healing. Advanced Drug Delivery Reviews. 2003;55(12):1595-1611.
8. Santhanam R, Rameli MAP, Al Jeffri A, Ismail WIW. Bovine-based collagen dressings in wound care management. Journal of Pharmaceutical Research International. 2020;32(3):48-63.
9. Swaim SF, Gillette RL, Sartin EA, Hinkle SH, Coolman SL. Effects of a hydrolyzed collagen dressing on the healing of open wounds in dogs. American Journal of Veterinary Research. 2000;61(12):1574-1578.
10. Xian LJ, Chowdhury SR, Saim ABS, Idrus RBH. Concentration-dependent effect of platelet-rich plasma on keratinocyte and fibroblast wound healing. Cytotherapy. 2015;17(3):293-300.
11. Yamauchi M, Hirohashi Y, Torigoe T, Matsumoto Y, Yamashita K, Kayama M, et al. Wound healing delays in α-Klotho-deficient mice with skin appearance similar to aged humans: Study of delayed wound healing mechanisms. Biochemical and Biophysical Research Communications. 2016;473(4):845-852.
12. You C, Li Q, Wang X, Wu P, Ho JK, Jin R, et al. Silver nanoparticle-loaded collagen/chitosan scaffolds promote wound healing via regulating fibroblast migration and macrophage activation. Scientific Reports. 2017;7(1):111.