Comparative Aspects of the Healing of Excisional Wounds on the Leg and Body of Horses

Abstract

Standardized 20 mm diameter excisional skin wounds were made on the body and distal limbs of 6 ponies at 18,12,4, and 2 weeks prior to biopsy. The results of comparative area analysis of leg and body wounds show that leg wounds take significantly longer to heal than body wounds. There is a longer preparatory phase and a greater amount of wound retraction in the leg wounds. At 12 weeks postwounding, the area of the epithelium covering the wound site is significantly larger in the leg wounds compared to the flank wounds. Histological examination of the wounds showed that there is less epithelialization of leg wounds at 2 and 4 week postwounding, and that the granulation tissue of these wounds extends slightly above the level of the adjacent skin. Within the granulation tissue of leg wounds, there are clefts filled with fibrin and inflammatory cells. Once epithelialization is completed, the leg wounds are covered by acanthotic epidermis with numerous large epidermal projections. In contrast, the flank wounds are covered by thin epidermis devoid of epidermal projections. One wound at 18 weeks postwounding had histological features typical of a keloid.HOUGH SKIN LACERATIONS occur commonly in T horses, particularly involving the distal limbs,',* little research has been conducted into equine skin wound healing. Most research into equine skin wounds has been directed toward developing reliable techniques for skin grafting. Although descriptions of both excisional and incisional wounds in equine skin are there is no presently available detailed description of the histology of the healing of incisional or excisional wounds in the horse.Lower leg skin wounds of horses are reported to have slower rates of wound contraction than those on the ~h o u l d e r .~ Wounds of the distal limbs frequently develop exuberant granulation tissue and therefore may pose difficult therapeutic problems.' Very extensive wounds of the upper body, however, heal rapidly with few complications.1° These differences in wound healing have not been explained, although a number of possible causes have beenThe purpose of this study was to investigate macroscopic and microscopic differences in the healing of standardized skin wounds created on the body and distal limbs of ponies. Materials and MethodsSix normal adult ponies were used. Leg and body wounds were made at 18, 12, 4, and 2 weeks prior to wound harvesting. The wounds were made with the animals under general anesthesia. The skin at each surgical site was clipped, shaved, and scrubbed with povidone iodine* scrub, and povidone iodine solution* was applied prior to wounding.Three wound types were made on the body and one lower limb of each pony on each of the four wounding dates: a 20 mm diameter excisional wound, a cryogenic wound approximately 20 mm in diameter made by the application of liquid nitrogent with skin temperature at the periphery of the wound monitored with thermocouples$ until it reached WC, and a 20 mrn diameter excisional wound to which liquid nitrogen was applied to the wound pe...

Copaiba oil in experimental wound healing in horses

“…The average contraction rate of the wounds at 21 DPO were significantly different between the metacarpal and lumbar regions; the lumbar region presenting a higher contraction rate in this period in both groups (Figure 2). The difference in the speed of healing between lumbar and metacarpal wounds in this study was expected, as it has been shown that lumbar wounds undergo a faster healing process, with a higher centripetal contraction, thinner granulation tissue, and a faster formation of crusts compared with metacarpal wounds (JACOBS et al, 1984;WHITE, 1995). According to JACOBS et al (1984) andWILMINK et al (1999), the delay in wound healing in distal regions of the limbs when compared with the trunk in the equine species, is due to a long healing phase, characterized by large retraction of the wound, low rates of epithelialization and early termination of wound contraction.…”

“…The difference in the speed of healing between lumbar and metacarpal wounds in this study was expected, as it has been shown that lumbar wounds undergo a faster healing process, with a higher centripetal contraction, thinner granulation tissue, and a faster formation of crusts compared with metacarpal wounds (JACOBS et al, 1984;WHITE, 1995). According to JACOBS et al (1984) andWILMINK et al (1999), the delay in wound healing in distal regions of the limbs when compared with the trunk in the equine species, is due to a long healing phase, characterized by large retraction of the wound, low rates of epithelialization and early termination of wound contraction. BERRY & SULLINS (2003) state that lower blood supply, oxygen tension and temperature in addition to the presence of insufficient quantities of cytokines, determine the different patterns of healing between the different anatomical regions of the horse.…”

Effect of Chitosan Gel on Wound Healing: Experimental Study in Donkeys

“…In such cases epithelization, must be relied upon to cover the remaining granulation bed (Swaim 1980;Jacobs et al, 1984). Finally, using minimum concentration of chitosan (0.1%), with shortest time (42-50-day), in the current study relative to other studies for complete healing in donkey's wound, give hopeful idea in handling of wound dressing in another species of animal particularly equine one.…”

“…In the current study, wound contraction started at 14 th day PW and proceeded rapidly during the following 4-5 weeks. The extent and the rate of wound contraction during this phase (the rapid healing phase) of wound healing depends upon the degree of myofibroblasts organization and the contraction of its actin contents (Jacobs et al, 1984& Wilmink et al, 1999b.…”

“…The rate of wound healing is determined by the sum of both wound contraction and epithelization (Jacobs et al, 1984). Epithelization of the wound occur by proliferation and migration of keratocytes to cover the surface of the wound.…”