Effects of split-thickness and full-thickness skin grafts on secondary graft contraction in horses.

Full-thickness, circular (4-cm diameter) cutaneous wounds were created on the metacarpi and metatarsi of 6 horses. Immediately after wounding, 1 wound on each horse received a meshed, split-thickness skin graft (0.64 mm) obtained from the ventrolateral aspect of the horse's thorax by use of a pneumatic dermatome, whereas a second wound received a meshed, full-thickness skin graft obtained from the pectoral area. In addition, sections of split-thickness and full-thickness grafts were refrigerated in a solution of McCoy's 5A medium, to which equine serum (10%) and gentamicin sulfate solution (16 mg/dl) were added. Ten days after wounding, 1 granulating wound on each horse was grafted with a stored, meshed, split-thickness graft, and 1 granulating wound on each horse was grafted with a stored, meshed, full-thickness graft. Areas of wounds were calculated from photographs taken of wounds on days 1, 5, 10, 15, 20, 25, and 30 after wounding. Time course of contraction was determined by use of a first-order mathematic model of changes in area through time. Rate constants of contraction for fresh or granulating wounds receiving full-thickness grafts did not differ significantly from those for fresh or granulating wounds receiving split-thickness grafts. Rate constants of contraction for grafted fresh wounds, however, were significantly less than those of grafted granulating wounds, regardless of whether a split-thickness or full-thickness graft was applied.     

Effects of hyperbaric oxygen on full-thickness meshed sheet skin grafts applied to fresh and granulating wounds in horses

OBJECTIVE: To determine the effects of hyperbaric oxygen therapy (HBOT) on full-thickness skin grafts applied to fresh and granulating wounds of horses. ANIMALS: 6 horses. PROCEDURES: On day 0, two 4-cm-diameter circular sections of full-thickness skin were removed from each of 2 randomly selected limbs of each horse, and two 4-cm-diameter circular skin grafts were harvested from the pectoral region. A skin graft was applied to 1 randomly selected wound on each limb, leaving the 2 nongrafted wounds to heal by second intention. On day 7, 2 grafts were harvested from the pectoral region and applied to the granulating wounds, and wounds grafted on day 0 were biopsied. On day 14, 1 wound was created on each of the 2 unwounded limbs, and the wounds that were grafted on day 7 were biopsied. All 4 ungrafted wounds (ie, 2 fresh wounds and 2 wounds with 1-week-old granulation beds) were grafted. The horses then received HBOT for 1 hour daily at 23 PSI for 7 days. On day 21, the grafts applied on day 14 were biopsied. RESULTS: Histologic examination of biopsy specimens revealed that grafts treated with HBOT developed less granulation tissue, edema, and neovascularization, but more inflammation. The superficial portion of the graft was also less viable than the superficial portion of those not treated with HBOT. CONCLUSIONS AND CLINICAL RELEVANCE: The use of HBOT after full-thickness skin grafting of uncompromised fresh and granulating wounds of horses is not indicated.     

Comparison of equine amnion and a nonadherent wound dressing material for bandaging pinch-grafted wounds in ponies

OBJECTIVE: To evaluate healing of pinch-grafted wounds on the distal aspect of the limbs of ponies bandaged with equine amnion or a standard nonadherent wound dressing material. ANIMALS: 6 ponies. PROCEDURE: A 2.5x2.5-cm full-thickness section of skin was removed from the dorsal aspect of each limb at the midpoint of the metacarpus or metatarsus. Six days later, wounds were grafted with partial-thickness pinch grafts. Half the wounds were bandaged with amnion, and the other half were bandaged with a nonadherent dressing. Bandages were changed every 3 days until wound healing was complete. At each bandage change, numbers of grafts lost were recorded, and wounds were measured. RESULTS: Percentage of grafts lost from wounds bandaged with amnion was not significantly different from percentage lost from wounds bandaged with the nonadherent dressing. Median healing time for wounds bandaged with amnion (30 days) was significantly less than median healing time for wounds bandaged with the nonadherent dressing (39 days). All wounds were healed by day 45. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that amnion can be used for bandaging pinch-grafted wounds on the distal aspect of the limbs of ponies.     

Effects of transplanted mesenchymal stem cells isolated from Wharton’s jelly of caprine umbilical cord on cutaneous wound healing; histopathological evaluation

The aim of this study was to investigate the effects of transplanted Wharton’s jelly mesenchymal stem cells (WJMSCs) of caprine umbilical cord on cutaneous wound healing process in goat. After collection of caprine pregnant uterus of mixed breed goats from abattoir, the Wharton’s jelly (WJ) of umbilical cord was harvested. The tissues were minced in ventilated flasks and explant culture method was used for separating mesenchymal stem cells (MSCs). The isolated cells were immunostained for Actin protein, histochemically assayed for the presence of alkaline phosphatase activity, and analyzed for detection of matrix receptors (CD44) and hematopoetic lineage markers (CD34), using flow cytometery. After The isolated cells, 3 × 10⁶ MSCs were stained with BrdU and prepared for transplantation to each wound. Four 3-cm linear full thickness skin incisions were made on both sides of thoracic vertebrate of four Raeini goats (two wounds on each side). The left wounds were implanted with MSCs in 0.6 ml of Phosphate buffer saline (PBS), and the right wounds considered as control group that received 0.6 ml of PBS. The samples were taken from the wounds 7 and 12 days after the wounding, and healing process was compared histologically between the two groups. Anti-BrdU staining showed that the transplanted cells were still alive in the wound bed during the study. The histopathological study revealed that re-epithelialization was complete at days 7 in treated wounds with WJMSCs, whereas in control wound the wounds still showed incomplete epithelialization 12 days after wounding. Also, microscopic evaluation showed less inflammation, thinner granulation tissue formation with minimum scar in the treated wounds in comparison with control wounds. In conclusion, this study demonstrates the beneficial effect of caprine WJMSCs in cutaneous wound healing in goat.     

Treatment of equine leg wounds using skin grafts: Thirty-five cases, 1975-1988

A retrospective study was conducted on 35 equine patients with lower leg wounds that were managed utilizing skin graft procedures. Two pinch graft, five punch graft, seven tunnel graft, eight split-thickness mesh graft and thirteen full-thickness mesh expansion graft procedures were performed in the initial treatment. The average wound size was 188 cm². Twentyfour cases had pregrafting complications: 10 wounds developed sequestra; three wounds were grossly contaminated and infected; and 11 cases developed granulation tissue complications prior to grafting. Graft failure following the initial procedure was seen in 12 cases and occurred with all techniques except pinch grafting. Graft failure was often attributable to poor quality of granulation tissue as well as anatomic site, especially the dorsal surface of the tarsus. An average of two additional grafting procedures was required to successfully treat initial failures. Pinch grafts took the longest time to epithelialize (70 days), followed by punch grafts (47 days). Both were similar in terms of being the least durable and least cosmetically acceptable of all techniques used. Split-thickness and full-thickness mesh expansion grafts were technically the most difficult, but showed the most rapid epithelialization (28 days), greatest durability, and the best cosmetic appearance. Tunnel grafts provided a practical technique for grafting cases which were either not suited for, or which had failed with, mesh expansion grafts.     

Comparison of the role of the subcutaneous tissues in cutaneous wound healing in the dog and cat

Objective— To describe and compare the contribution of the subcutaneous tissues to 1st and 2nd intention cutaneous wound healing in the dog and cat.
Study Design— Experimental study.
Animals— Domestic shorthaired cats (n=6) and 6 beagle dogs.
Methods— Paired wounds were created on either side of the dorsal midline; the subcutaneous tissue was removed on 1 side and left intact on the other. Square, open wounds of the dorsal aspect of the thorax were observed for 21 days to monitor granulation tissue formation, wound contraction, epithelialization, and total healing (contraction+epithelialization). Breaking strength of sutured linear wounds was measured 7 days after wounding. Laser-Doppler perfusion imaging (LDPI) was used to measure cutaneous perfusion.
Results— First intention healing: subcutaneous tissue removal had no consistent effect on sutured wound strength at 7 days in dogs or cats. Second intention healing: removal of subcutaneous tissue reduced wound perfusion, granulation, contraction, epithelialization, and total healing. Granulation tissue formation and wound contraction were delayed to a significantly greater degree in cats than in dogs ( P <.05). Two dogs (33%) had minor wound infections.
Conclusions— The subcutaneous tissues make an important contribution to 2nd intention cutaneous healing. Dog and cat wounds had delayed 2nd intention healing when subcutaneous tissues were removed; wounds in dogs, but not cats, had largely recovered from this delay by 21 days.
Clinical Relevance— Extensive debridement of subcutaneous tissue may delay wound healing particularly in feline patients. A higher risk for wound infections may accompany extensive removal of subcutaneous tissues in dogs.     

Effects of 3 biologic dressings on healing of cutaneous wounds on the limbs of horses

Three biologic dressings [split-thickness allogeneic skin (STS)], allogeneic peritoneum (P), and xenogenic porcine small intestinal submucosa (PSIS)] were studied to determine their effects on bacterial proliferation, inflammatory reaction, vascularization, and overall healing and to compare the effects of these dressings with the effects of a nonbiologic dressing, a nonadherent synthetic pad (NASP). A medial wound (3 cm in diameter) and 2 lateral wounds (2 cm in diameter) were created at the junction of the proximal and middle thirds of each metacarpus and metatarsus in 5 horses. Each medial wound and the proximolateral wound received an STS, P, PSIS, or NASP dressing on day 8 after wounding. The other lateral wound received an NASP dressing. Bacterial proliferation, inflammatory reaction (histologic changes), and drhessing vascularization were evaluated 6 d after application of the dressing. Percentages of contraction and epithelialization, as well as healing time, were determined when the wounds had completely epithelialized. The practical applicability of the different dressings to equine wound management was also assessed. No significant difference was detected in the parameters evaluated among the treated wounds or between the treated and control wounds. The biologic dressings had no effect on infection, inflammatory response, or healing time. Vascularization was not identified in any of the biologic dressings. The PSIS and P dressings required numerous applications over the study period. The STS dressings are more practical than PSIS and P dressings owing to ease of application and stability. Thus, these biologic dressings offer no apparent advantage over a nonbiologic dressing for treatment of small granulating wounds.     

The effect of ambient temperature and type of wound on healing of cutaneous wounds in the common garter snake (Thamnophis sirtalis).

The effects of ambient temperature (13.5 degrees C, 21 degrees C, 30 degrees C) and type of wound on healing of skin wounds were evaluated in common garter snakes (Thamnophis sirtalis). Linear unsutured incisions and circular excisional wounds were evaluated grossly and microscopically in three snakes held at each temperature at each of two, five and ten days after surgery. Linear sutured and unsutured incisions and circular and square excisional wounds were similarly evaluated three and six weeks after wound production in groups of six snakes held at each temperature. The rates of stabilization of wound margins, scab formation, migration and maturation of the regenerating epithelium, resolution of dermal inflammation, and fibroplasia varied directly with temperature. The inflammatory reaction to wounding was similar in character and intensity in snakes held at all three temperatures two days after surgery. Unsutured linear incisions, compared to sutured incisions, tended to have more rapid epithelial maturation and a less intense inflammatory response. Healing of square and circular excisional wounds was similar; contraction of round wounds was slightly more irregular and, at a few observations, dermal maturation was slower and inflammation more widespread. It was concluded that healing of skin wounds can be accelerated by holding reptiles at the upper end of their voluntary temperature range. Wounds, if possible, should be created along the axis of lines of skin tension. Suturing small incisional wounds may not be advantageous.     

Effects of Chlorhexidine Diacetate and Povidone-lodine on Wound Healing in Dogs

To correlate the results of an in vitro study with clinical response, the effects of 0.005 and 0.05% chlorhexidine diacetate and 0.1 and 1.0% povidone-iodine concentrations on wound healing were evaluated in five beagle dogs. Full-thickness skin wounds (2 X 2 cm) were irrigated once daily for 14 days with the antiseptic solutions or physiologic-buffered saline. Chlorhexidine diacetate 0.05% had significantly more bactericidal activity than povidone-iodine and saline, and both chlorhexidine diacetate concentrations had residual effects 6 hours after irrigation. Neither povidone-iodine nor saline had significant bactericidal activity. The percentages of unhealed wound area and wound contraction were calculated 7, 14, and 21 days after wounding. Healed wound area and contraction were similar in wounds treated with chlorhexidine diacetate and povidone-iodine. However, wounds treated with chlorhexidine diacetate had more healed wound area on days 7 and 14 and more contraction on days 7, 14, and 21 than saline-treated wounds. At the concentrations tested, chlorhexidine diacetate irrigations provided bactericidal activity and were more beneficial to wound healing than irrigations with saline alone. These results suggest that concentrations of chlorhexidine diacetate which are cytotoxic to tissue culture fibroblasts in vitro do not interfere with wound healing in vivo.     

The use of vacuum-assisted closure therapy for the treatment of distal extremity wounds in 15 dogs

Objective— To evaluate clinical outcome after vacuum-assisted closure (VAC) therapy in dogs with traumatic wounds located in the distal extremities and report our early experience with VAC.
Study Design— Retrospective study.
Animals— Dogs (n=15) with traumatic distal extremity wounds.
Methods— Medical records (1999–2003) of dogs with traumatic injuries to the distal extremities managed by VAC were evaluated. Data included signalment, location of wound, time until surgical intervention, wound reconstruction methods, orthopedic procedures, outcome, complications associated with VAC, and length of hospitalization.
Results— The mean number of days until reconstruction was 4.6 days (range, 2–7 days). Reconstructive surgery was successful in all cases. Mean hospitalization was 9.7 days (range, 6–16 days). Complications included dermatitis at the wound margin and loss of vacuum causing wound desiccation.
Conclusion— VAC therapy can be used to achieve adequate management of traumatic distal extremity wounds. VAC provides an effective method of securing skin grafts over the wound bed.
Clinical Relevance— VAC therapy can be used as an ancillary treatment for distal extremity wounds in dogs before surgical repair as well as a method for securing skin grafts to the wound bed.     

The modified Meek technique as a novel method for skin grafting in horses: evaluation of acceptance, wound contraction and closure in chronic wounds

REASONS FOR PERFORMING STUDY: The acceptance of skin grafts in horses is unpredictable and the final cosmetic result can be disappointing. Besides movement and infection, graft failure is often caused by chronic inflammation, inherently present during second intention healing of limb wounds in horses. In human burns affected by infection and inflammation, the acceptance of the island skin grafts of the modified Meek technique appeared to be better than meshed sheet skin grafts. HYPOTHESIS: The percentage take of Meek micrografts is higher than of other techniques; and rates of both wound contraction and epithelialisation are increased. METHODS: Large traumatic limb wounds of 13 horses healing by second intention were grafted using the modified Meek technique. Photographs of the wounds were taken at set intervals. Wound areas, and areas of acceptance and rejection were determined using a digital image post processor (Scion Image). The percentages of take, wound contraction and epithelialisation were calculated. RESULTS: The initial mean wound area was 7500 mm2. Graft acceptance was mean +/- s.d. 93.7 +/- 5.9%. Wound closure was due to contraction (55.2 +/- 11.1%) and epithelialisation (44.8 +/- 11.1%) and resulted in a 96.7 +/- 3.6% reduction of the initial wound area 29.1 +/- 6 days after grafting. All wounds showed functional and cosmetic healing. CONCLUSIONS: The method for skin grafting in horses achieved higher percentages of take than reported previously and consistent cosmetic and functional results. The grafts increased not only the rate of epithelialisation but also had a strong positive effect on wound contraction, resulting in rapid closure and smaller scars. POTENTIAL RELEVANCE: The modified Meek technique proved to be a novel technique for skin grafting equine wounds in clinical practice, which can be performed easily. The molecular background of the increase of wound contraction by the grafts may provide a clue in the search for medicinal stimulation of wound contraction during second intention healing.     

Spatial and temporal expression of types I and II receptors for transforming growth factor beta in normal equine skin and dermal wounds

OBJECTIVE : To describe immunolocalization of TGF-beta receptors (RI and RII) in normal equine skin and in thoracic or limb wounds, healing normally or with exuberant granulation tissue (EGT). STUDY DESIGN : Group A: six wounds on one metacarpus and one midthoracic area. Group B: six wounds on both metacarpi, one of which was bandaged to stimulate EGT. Immunohistochemistry was used to detect RI and RII expression in wound margins. ANIMALS : Eight horses, randomly assigned to one of two study groups. METHODS : Neutralizing polyclonal anti-rabbit RI and RII antibodies were used to detect spatial expression of RI and RII in biopsies obtained before wounding, at 12 and 24 hours, and 5, 10 and 14 days after wounding. RESULTS : RI and RII were co-localized in both unwounded and wounded skin. There were no differences in cell types staining positively between tissues obtained from the limb and the thorax, or from normally healing limb wounds and limb wounds with EGT, at any time. Because of increased cellularity within EGT, staining intensity of limb wounds with 'proud flesh' was greater than limb wounds healing normally, and thoracic wounds, during the proliferative phase of repair. CONCLUSIONS : Strong expression of RI and RII, particularly in limb wounds with EGT, suggested that signalling for stimulation of matrix proteins is in place to contribute to scarring. CLINICAL RELEVANCE : This information may help determine the appropriate time for using receptor antagonists to prevent scarring of limb wounds of horses.     

P-2 Evaluation of the influence of sex, diet and time on skin pH and surface lipids of cats

Liquorice, a derivative of the root of Glycyrrhizia glabra, has been proposed as a treatment for gastric ulcers. Here, a preparation of liquorice combined with sesame oil was evaluated in experimental wound healing. The study was carried out in two female 10-month-old Holstein calves. An area of 10 × 10 cm on each side of the thorax of the animals was surgically prepared and infiltrated with local anaesthetic. Eight uniform skin wounds were created in two rows with an 8-mm biopsy punch on each prepared area. Each side of an animal was used to evaluate one treatment (Groups 1–4). To make the mixture, powdered and sieved liquorice (16 g) was mixed with sesame oil (36 g) to make a suspension. The wounds were treated for 7 days. The wounds of Groups 1–3 were rinsed daily with normal saline, after which the mixture of liquorice and sesame oil (Group 1) or only the sesame oil (Group 2) was applied to the wounds. In Group 4, no treatment was applied. All wounds were left open. On day 8, skin biopsies were taken from the wounds for histopathologic study. In Group 1, seven wounds (87%) showed moderate granulation tissue, mild scab formation, and complete re-epithelialization. In Group 2, there was massive scab formation with no granulation tissue and minimal re-epithelialization. In Groups 3 and 4, mild granulation tissue, severe scab formation and very limited re-epithelialization were observed. We conclude that a preparation of liquorice and sesame oil can be an effective remedy for wound healing.
Funding: Self-funded.     

Healing of cutaneous wounds in the common garter snake (Thamnophis sirtalis).

Healing of cutaneous wounds was studied in groups of common garter snakes (Thamnophis sirtalis) held at 13.5 degrees C, 21 degrees C and 30 degrees C. Linear unsutured incisions and circular excisional wounds were evaluated two, five, and ten days after surgery, while linear sutured and unsutured incisions and circular and square excisional wounds were studied three and six weeks after wound production. The sequence of events during healing was the same for all experimental situations. The epithelial margins of the wounds moved freely over exposed epaxial muscle until an exudate of fibrin and inflammatory cells caused adhesion. Heterophils and macrophages were present two days after wounding. Heterophils were present throughout the wound while macrophages were concentrated in areas containing fibrin and proteinaceous exudate. Fibroblasts moved laterally into the wound from the adjacent dermis producing a flat dermal scar oriented parallel to the wound surface. Epithelial cell hypertrophy and hyperplasia occurred in a zone extending up to 1.5 mm from the margin of the wound. A tongue of flattened epithelial cells extended across the wound surface, mingling with the superficial crust and migrating over eosinophilic fibrillar material. Maturation of the new epithelium, indicated by formation of a distinct basal layer, rounding of superficial cells and keratin production, began at the wound margins before the epithelial spurs linked. The epithelium over healed wounds appeared normal, but the dermis did not reorganize to form scales. Reptilian and mammalian healing differ in the character of the inflammatory reaction, the pattern of fibroplasia, and the interaction between epithelial and dermal repair.     

Effect of wound location and the use of topical collagen gel on exuberant granulation tissue formation and wound healing in the horse and pony

Preformed collagen gel was topically applied to cutaneous wounds of the equine dorsal fetlock (thoracic limb) and metatarsal regions to evaluate the effect on exuberant granulation tissue production and wound healing. In 6 horses and 3 ponies (less than 140 cm high at the withers and less than 365 kg), 36 standardized cutaneous limb wounds were surgically induced (4 wounds/animal); 18 wounds were treated topically with collagen gel, and 18 wounds were not treated (controls). Collagen gel was initially applied to the wound at 0, 2, or 7 days after wound formation (groups 1, 2, and 3, respectively). Four measurements were regularly made: amount of wound contraction and the size of the granulation bed, epithelial covering, and total wound. Sequential skin and wound biopsies were evaluated histologically to assess wound healing. Using a computer, data were analyzed for differences in the 4 measurements between treated and control wounds, between fetlock wounds and metatarsal wounds, and among groups 1, 2, and 3. Analyses were performed on days 15 and 45 of wound healing and on the final day of healing. A significant difference (P greater than 0.05) in the production of exuberant granulation tissue, rate of epithelialization, or degree of wound contraction was not detected between the collagen-treated and control wounds. Total healing time and final scar size were similar. Wound healing patterns were significantly different (P less than 0.05) in the fetlock wounds and metatarsal wounds. All wounds enlarged up to day 15 with fetlock wounds enlarging significantly more than did the metatarsal wounds.(ABSTRACT TRUNCATED AT 250 WORDS)     

Laminin receptor 1 is differentially expressed in thoracic and limb wounds in the horse

Healing of wounds located on the distal limbs of horses is often complicated by retarded epithelialization and the development of exuberant granulation tissue (proud flesh). Treatments that definitively resolve this pathological process are still unavailable. Molecular studies of the repair mechanism might contribute to the development of new therapeutic strategies. The study presented herein aimed to clone the full length cDNA and to study the spatio-temporal expression profile of mRNA and protein for LAMR1, previously attributed a role in wound epithelialization, during the repair of body and limb wounds in the horse. Cloning was achieved by screening a cDNA library previously derived from 7-day wound biopsies. Expression was studied in unwounded skin and in samples from 1-, 2-, 3-, 4- and 6-week-old wounds of the body and limb. Temporal gene expression was determined by real time polymerase chain reaction (RT-PCR) while protein expression was mapped immunohistochemically. Full-length cDNA for equine LAMR1 was shown to be highly similar to that of other species. The mRNA expression of LAMR1 was significantly up-regulated only in thoracic wounds, 4 and 6 weeks following wounding (upon epithelialization). Cutaneous wounding induced protein expression at both locations. Our data suggest that up-regulation of LAMR1 protein might favour epithelialization during wound healing. However, its interaction with ligands other than laminin complicates data interpretation. Future studies should quantitatively verify the temporal expression of this protein in order to provide the basis for targeted therapies that might enhance epithelialization.     

FC-62 Pale sulphonated shale oil exhibits antimicrobial and tissue repairing effects in wound healing

Oleaster ( Elaeagnus angustifolia ) is a small tree that grows throughout Iran. Using smashed tree leaves combined with olive oil is proposed in one ancient Iranian text as a good remedy for wound healing. Our objective was to evaluate this remedy experimentally. The study was carried out in two female 10-month-old Holstein calves. An area of 10 × 10 cm on each side of the thorax was surgically prepared and infiltrated with local anaesthetic. Eight uniform skin wounds were created in two rows with an 8-mm biopsy punch on each prepared area. Each side of an animal was used to evaluate one treatment (Groups 1–4). To make the mixture, fresh oleaster leaves (50 gm) were smashed with a pestle and mixed with olive oil (25 gm). The wounds were treated for 7 days. The wounds of Groups 1–3 were rinsed daily with normal saline, after which the mixture of oleaster and olive oil (Group 1) or only the olive oil (Group 2) was applied. In Group 4, no treatment was applied. All wounds were left open. On day 8, skin biopsies were taken from the wounds for histopathologic study. Group 1 wounds all showed mild granulation tissue, scab formation and complete re-epithelialization. In Group 2, there was mild granulation tissue, massive scab formation and minimal re-epithelialization. In Groups 3 and 4, mild granulation tissue, severe scab formation and very limited re-epithelialization were observed. We conclude that a fresh oleaster leaf preparation can be an effective remedy for wound healing.
Funding: Self-funded.     

FC‐61 The role of a liquorice preparation in healing of experimental wounds in calves: a histopathologic study

Liquorice, a derivative of the root of Glycyrrhizia glabra, has been proposed as a treatment for gastric ulcers. Here, a preparation of liquorice combined with sesame oil was evaluated in experimental wound healing. The study was carried out in two female 10‐month‐old Holstein calves. An area of 10 × 10 cm on each side of the thorax of the animals was surgically prepared and infiltrated with local anaesthetic. Eight uniform skin wounds were created in two rows with an 8‐mm biopsy punch on each prepared area. Each side of an animal was used to evaluate one treatment (Groups 1–4). To make the mixture, powdered and sieved liquorice (16 g) was mixed with sesame oil (36 g) to make a suspension. The wounds were treated for 7 days. The wounds of Groups 1–3 were rinsed daily with normal saline, after which the mixture of liquorice and sesame oil (Group 1) or only the sesame oil (Group 2) was applied to the wounds. In Group 4, no treatment was applied. All wounds were left open. On day 8, skin biopsies were taken from the wounds for histopathologic study. In Group 1, seven wounds (87%) showed moderate granulation tissue, mild scab formation, and complete re‐epithelialization. In Group 2, there was massive scab formation with no granulation tissue and minimal re‐epithelialization. In Groups 3 and 4, mild granulation tissue, severe scab formation and very limited re‐epithelialization were observed. We conclude that a preparation of liquorice and sesame oil can be an effective remedy for wound healing. Funding: Self‐funded.     

Effects of 25% propylene glycol hydrogel (Solugel) on second intention wound healing in horses

OBJECTIVE: To evaluate the effect of a commercially available 25% propylene glycol hydrogel preparation (Solugel; Johnson and Johnson Medical, North Ryde, Australia) on healing of full-thickness skin wounds on the distal aspect of the limb in horses. STUDY DESIGN: Experimental. ANIMALS: Eight Standardbred horses. METHODS: Standardized (2.5 x 2.5 cm) full-thickness skin wounds were created over the mid-dorsomedial aspect of both metacarpi in 8 horses. One wound in each horse was dressed with saline solution (0.9% NaCl) soaked gauze, and one was treated with Solugel under dry regular gauze; wounds were then bandaged with gauze-coated cotton wool and elastic adhesive bandages. Wounds were videorecorded and rebandaged twice weekly until healed. Wound healing variables were measured from the videorecordings using a computer software package and analyzed as a randomized complete block design with repeated measures. Where necessary variables were made positive for analysis; significance was set at P <.05. RESULTS: The area of the wound at the first bandage change did not vary between treated and untreated wounds. Treatment had no effect on the total rate of healing, rate of healing during the retraction phase of healing, rate of healing after the retraction phase was complete, or the amount the wounds retracted. CONCLUSIONS: Using this model of wound healing, Solugel had no effect on second intention healing of distal limb wounds in horses. CLINICAL RELEVANCE: Solugel does not appear to have any beneficial effect on healing of small full-thickness skin wounds to the distal limb of horses.     

Autologous, split skin transplantation on the lower limbs of horses.

The skin grafting experiments were carried out on the cannon regions of horses to throw light on four matters relating to split skin transplantation. They were: The thickness of donor split skin that would provide good wound cover and still leave adequate tissue to permit uneventful healing at the donor site; whether split skin grafts were more readily accepted on fresh than on granulating wounds; the size of wounds that would benefit from grafting; and the maximum size of graft that would be readily accepted. The findings were: Split skin grafts 0.76 mm thickness gave the best results although grafts 0.63 mm thickness were satisfactory; split skin grafts were accepted more readily on fresh wounds than on granulating tissue; wounds which exceeded 1/10th of the skin area on the cannon region justified grafting; the upper limit in size was not established as the largest grafts used were more readily accepted than smaller grafts.