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Effect of bandaging on second intention healing of wounds of the distal limb in horses
Abstract
To evaluate the effect of a non-occlusive dressing incorporated in a 3-layer bandage on second intention healing of wounds of the distal portion of the limb.
Untreated wounds in 33 adult horses used in four studies using the same wound-healing model conducted over 5 years.
Standardised, full-thickness wounds were made in the skin overlying the dorsomedial aspect of the mid-metacarpus; 17 horses were bandaged with a non-occlusive dressing covered by gauze-coated cotton wool that was compressed with adhesive tape; 16 horses were left unbandaged. Wounds were photographed weekly for 9 weeks and the images were analysed electronically.
There were significant effects associated with bandage (P < 0.0001), week (P < 0.001), and bandage by week interaction (P < 0.0001). There was no difference in wound area at the first time-point after wound creation (P = 0.38). After week 1, there was a difference between bandaged and unbandaged wounds in wound area at each measurement until the end of the study. Bandaged wounds showed greater and more prolonged retraction. Unbandaged wounds retracted for 2 weeks before beginning to contract, whereas bandaged wounds continued to retract for 3 weeks. In bandaged wounds excess granulation tissue required regular trimming, but not in unbandaged wounds. There was no difference between groups in the total days to healing or the overall rate of healing.
These results should be treated with caution until validated with contemporaneous, controlled studies. Covering a wound with a non-occlusive dressing in a 3-layer bandage led to greater wound retraction, modulated the rate of wound contraction and promoted excessive granulation tissue. If excessive granulation tissue is excised regularly, bandaging has no effect on total time to healing.
... This was consistent with our hypothesis that the prevalence of EGT formation would be reduced in wounds treated with the SES compared to standard bandaging. However, a previous study showed that covering a wound with a nonocclusive dressing in a 3-layer bandage modulated the rate of wound contraction and promoted EGT [19]. It is therefore difficult to conclude that the absence of EGT on T1 treated wounds is related to the application of SES and/or the lack of covering bandage. ...
... In the case of a distal limb wound in a horse, it is generally accepted that after cleaning the wound, a dressing should be applied and covered with a bandage to decrease contamination and oedema, absorb exudate, minimise movement and protect against more trauma [19]. It is recommended to change bandages every 3 to 5 days depending on the discharge and evolution of the wound healing [21]. ...
... The transient increase in wound volume that occurred in wounds treated with standard bandaging did not affect the healing time. This was supported by a previous report [19]. ...
Objectives
To evaluate secondary intention wound healing in the horse’s limbs when treated with the synthetic epidermis spray (Novacika®, Cohesive S.A.S, France) or with a standard bandaging technique.
Methods
Six Standardbred mares were included in the study. Four 2.5 x 2.5 cm full-thickness skin wounds were created on each thoracic limb. Two wounds were located on the dorsoproximal aspect of the cannon bone and the other two at the dorsoproximal aspect of the fetlock. Six hours after creation, wounds were randomly treated with synthetic epidermis spray or standard bandaging. The wounds were assessed every 4 days by gross visual assessment and using a 3D imaging camera. Analysis was performed with a 3D imaging application.
Results
Out of 46 wounds, 22 showed exuberant granulation tissue and were part of the standard bandaging group. Whether the wounds were treated with synthetic epidermis spray or standard bandaging, the time for healing was the same.
Conclusion
The synthetic epidermis spray studied in this model has allowed healing without the production of exuberant granulation tissue but did not reduce the median wound healing time compared to a standard bandaging technique. The synthetic epidermis spray is potentially an interesting alternative for the management of secondary intention wound healing of superficial and non-infected distal limb wounds in adult horses on economical and practical aspects. However, all statistical inference (p-values especially) must be interpreted with caution, given the size of the sample.
... Surgical resection creates an evenly levelled wound surface and sets a new stimulus for healing, thereby aiming to support the endogenous self-healing properties of the equine patient (Wilmink and van Weeren, 2005). Resection of EGT is suggested to shorten healing duration (Dart et al., 2009). Of the 35 studies that report treatment of EGT, 19 describe surgical resection of excessive tissue. ...
... Numerous studies have investigated bandaging to treat EGT, although results remain controversial (Supplementary Table S2). While the combination of a non-adhesive bandage and topical corticosteroids was reported to increase the percentage of contraction (Barber, 1990), other studies observed that bandages prolonged and reinforced initial retraction and delayed contraction (Theoret et al., 2002;Dart et al., 2009). The frequency of bandage change also may affect EGT formation. ...
... However, this effect was scientifically difficult to confirm. If poorly applied, bandages may do harm, which is reflected in the repeated observation that bandaged wounds developed EGT, while their unbandaged controls did not (Theoret et al., 2002;Berry and Sullins, 2003;Wilmink and van Weeren, 2005;Dart et al., 2009;. In addition, experimental and therapeutic studies have used bandages to induce EGT (Lepault et Table 3 List of controlled clinical trials addressing EGT (n = 35). ...
Exuberant granulation tissue (EGT) is often observed during second intention wound healing in horses. Despite its impact on wound care, the basic mechanisms leading to EGT are still unclear and effective strategies to prevent and/or treat EGT are lacking. The development of EGT is a poorly understood, multifactorial process involving hyperproliferating fibroblasts and malfunctional differentiation of keratinocytes, suboptimal wound contraction, dysfunctional vascularisation, and chronic inflammation. To consolidate and describe basic and clinical research literature on EGT and to identify knowledge gaps and opportunities for future research, a search was systematically conducted using predefined search terms. Subsequently, a scoping review was conducted using specific criteria to select the peer-reviewed literature that described methods to treat and/or prevent EGT. Proposed mechanisms of effects as well as results and main conclusions were extracted and tabulated. The systematic search resulted in 1062 publications in PubMed and 767 in Web of Science. Twenty additional studies were later included. Of these, 327 studies were reviewed for the narrative review on basic research and 35 controlled clinical trials were eligible for the scoping review. All 35 studies were conducted in university hospitals, and all but one involved surgically induced non-infected wounds. The study population was predominantly horses (n = 230) with a small number of ponies (n = 18) and donkeys (n = 14). In conclusion, there remains a strong need for evidence-based recommendations on EGT treatment, preferably using multi-centre studies that represent the general population of horses, include higher numbers of animals, and are performed in naturally occurring wounds. This narrative and scoping review also emphasises the importance of incorporating basic research knowledge in the study design of clinical trials.
... These results confirm the association between securely regulated inflammatory response in vivo and successful wound repair and tissue regeneration [49,50]. It supports previous research which links the effect of weak and persistent inflammatory phase of wound healing with the production of excessive granulation tissue and delaying wound healing of equine lower limb wounds [4,51]. (Fig. 7A, bar ¼ 500 nm, 5000Â). ...
... TGFb1 is known to play a significant role in arranging the process of wound healing in donkeys, an imbalance in the expression of TGF isoforms have been concerned in tissue fibrosis, post-injury scarring, and production of excessive granulation tissue in distal limb wound in donkeys [48,52e57]. Inhibitors of TGFb1 have been revealed to reduce the inflammation and scarring [18,51,58]. ...
... Moreover, SSD cause cosmetic abnormality (argyria or blue-gray coloration) on prolonged use [50], whereas the positive cosmetic effects of AgNPs on the wound healing might be related to the regulation of the TGFb1 production. The TGFb1 isoforms have been reported to play a significant role in arranging the complex network of cytokines and growth factors responsible for reducing inflammation and scarring [18,51,58] during the second-intention wound healing in the donkey [69]. ...
Healing of equine distal limb wound represents a challenging problem and occupies a vital place in
everyday pathology. Silver nanoparticles (AgNPs) are attractive materials for many researchers because of
their anti-inflammatory, antibacterial, and wound-healing properties; as such, this study was performed to
investigate the healing efficacy of AgNPs on second-intention wound healing in five clinically healthy
donkeys as compared with silver sulfadiazine. Wound healing was evaluated clinically (healing rate [%],
healing time [days], epithelialization rate [%]), whereas the antimicrobial effect of AgNPs was evaluated by
comparing with amoxicillin/metronidazole mixture. In addition, angiogenesis, re-epithelialization, cellular
invasion, and scar width were characterized by histopathology and the immunohistochemical localization
of transforming growth factor beta 1 (TGFb1) was assessed, along with the ultrastructure of the AgNPstreated wounds. Accelerated wound healing, better cosmetic appearance, and efficient antimicrobial effect were achieved with AgNPs dressing. Superiority of AgNPs in wound healing was approved histopathologically by the early granulation tissue formation, higher epithelialization (%), and reduced scar
width. Positive TGFb1 immunoreactivity with macrophage, fibroblast, and endothelial localization was
reported during the inflammatory and the proliferative phase; however, it has reduced during the
remolding phase producing a faster scar-free wound healing. The cytocompatibility of the AgNPs with
fibroblast was demonstrated by the integrity of the cellular and nuclear membrane with nonfragmented
nucleoli, as detected by the ultrastructural examination. It could be concluded that AgNPs represent a step
forward and a promising alternative dressing in wound healing in donkeys through its anti-inflammatory,
antimicrobial, and favorable cosmetic properties, in addition to its role in regulation of TGFb1 production
... 5 Many different treatments have been investigated to combat EGT, but none have proven universally successful. [7][8][9][10] Although various treatments have been associated with improvements in the early stages of healing for wounds in the distal aspect of horses' limbs, none have prevented EGT formation or reduced the time to wound closure, compared with that of untreated control wounds. [7][8][9][10] Hyperosmolar nanoemulsion is a novel compound that combines lipophilic (membrane disrupting) nanoemulsions with hyperosmotic saccharides. ...
... [7][8][9][10] Although various treatments have been associated with improvements in the early stages of healing for wounds in the distal aspect of horses' limbs, none have prevented EGT formation or reduced the time to wound closure, compared with that of untreated control wounds. [7][8][9][10] Hyperosmolar nanoemulsion is a novel compound that combines lipophilic (membrane disrupting) nanoemulsions with hyperosmotic saccharides. a The hyperosmotic saccharides are similar to sugar or honey treatments, but when these are combined with lipophilic emulsions (eg, thymol), the 2 components are shown to act synergistically to inactivate isolates of Escherichia coli, Enterococcus faecalis, and Staphylococcus aureus, including methicillinresistant S aureus. ...
... 6,18 It has been concluded that the presence of a bandage alone may lead to EGT formation owing to low ambient oxygen tension. 7,8 Decreased oxygen tension stimulates angiogenesis and fibroplasia, which contribute to EGT formation. 19,20 The objective of the study reported here was to evaluate the effects of HNE, SSC, and TAO on healing of experimentally induced skin wounds on the distal aspects of the limbs of horses. ...
OBJECTIVE To determine the effects of 3 topically applied treatments (1% silver sulfadiazine cream [SSC], triple antimicrobial ointment [TAO], and hyperosmolar nanoemulsion [HNE]) on microbial counts, exuberant granulation tissue (EGT) development, and reepithelialization of contaminated wounds at the distal aspect of the limbs of horses.
ANIMALS 8 healthy adult horses.
PROCEDURES A 2.5 × 2.5-cm, full-thickness, cutaneous wound was created at the dorsal aspect of each metacarpus and metatarsus (1 wound/limb/horse), covered with nonadhesive dressing, and bandaged. Wounds were inoculated with bacteria and fungi the next day. Each wound on a given horse was randomly assigned to 1 of 4 treatment groups (SSC, TAO, HNE, or no topical treatment [control]). Bandage changes, culture of wound samples, treatments, photography for wound measurements, and biopsy were performed at predetermined time points. Time (days) until wound closure, number of EGT excisions, microbial counts, and scores for selected histologic characteristics were compared among groups.
RESULTS Median time to wound closure for all groups was 42 days. Time to wound closure and histologic characteristics of wound healing did not differ among groups. Least squares mean microbial counts were significantly higher for HNE-treated wounds on days 9 and 21, compared with SSC-treated and TAO-treated wounds, but not controls. Proportions of SSC-treated (7/8) or HNE-treated (5/8) wounds needing EGT excision were significantly greater than that of TAO-treated (1/8) wounds. The proportion of SSC-treated wounds with EGT excision was greater than that of controls (3/8).
CONCLUSIONS AND CLINICAL RELEVANCE None of the treatments resulted in more rapid wound closure, compared with that for untreated control wounds under the study conditions. When treatment is warranted, TAO may help to limit EGT formation.
... In addition to the significant effects of MEBO on wound area and granulation tissue scores, complete wound healing times were significantly shorter in MEBO-treated wounds that healed faster than the control wounds. Lower extremity wounds have been known to be life threatening and crippling to horses (Dart et al., 2009). Factors including increased risk of bacterial contamination and infections, decreased blood supply, reduced soft tissue support, and wounds over areas of high motion all contribute to prolonged healing, unsatisfactory cosmetic outcomes, and poor functional outcomes. ...
... The present study achieved complete wound closure and mean healing time was 35 days. Average healing times for lower leg wounds in horses treated with standard dressings, as well as advanced wound care approaches, typically range from several weeks to months (Fretz and Li, 1992;Petersen et al., 1999;Bello, 2002;Dart et al., 2009;Morgan et al., 2009). In an analysis of 33 equines in four wound healing studies of the distal limb, Dart et al (2009) observed greater and more prolonged wound retraction and presence of excessive granulation tissue following standard bandaging than with unbandaged controls. ...
... Average healing times for lower leg wounds in horses treated with standard dressings, as well as advanced wound care approaches, typically range from several weeks to months (Fretz and Li, 1992;Petersen et al., 1999;Bello, 2002;Dart et al., 2009;Morgan et al., 2009). In an analysis of 33 equines in four wound healing studies of the distal limb, Dart et al (2009) observed greater and more prolonged wound retraction and presence of excessive granulation tissue following standard bandaging than with unbandaged controls. No differences in healing rates (cm 2 /day) or healing times were observed in the studies between the two groups (P = 0.43), with a mean total of 75 days to healing of bandaged wounds versus 66 days for unbandaged wounds (Dart et al., 2009). ...
... Wounds localized at the trunk region are less problematic and heal at a faster rate than wounds located at the distal aspect of the limb [1]. In the horse, complications such as wound infection, formation of exuberant granulation tissue (EGT) and hypertrophic scarring are frequent [2] especially at the distal aspect of the limb [3]. The EGT or "Proud Flesh" is considered similar to the keloid of the human skin [3,4] and, together with wound contamination/infection [3], is currently the most complicated aspect of wound management in equine. ...
... Disregulation of fibroblast growth [5], decreased rates of contraction [6,7], microvascular occlusion [4], disregulated apoptotic process by hypoxia [4], changes in the expression of the TGF-β1 [8,9], inefficient inflammatory response to trauma [10], disparity between the synthesis and degradation of collagen [11], down-regulation of specific gene expression [12] and lower oxygen saturation values of the equine limb compared to the body [4] may be involved. The major factors which seem to play an important role in promoting EGT formation are wound location [3,14] fully-occlusive, semi-occlusive or pressure bandaging [1,2,3,6,14,16,17,18,19], with the exception of silicone gel dressing [20], but not body size (height and weight) [21,22] contrary to what reports [23]. It has been demonstrated that the predisposition of equine to EGT formation is strongly influenced by genes and it is also present in miniature Caspian horses where height and weight are less or similar to ponies [21,22]. ...
... Historically most of the research on second-intention healing in horses has focused on superficial full-thickness skin wounds having a small diameter (2,5cm) which are hardly representative of the accidental wounds commonly seen in clinical practice [30]. Creating a more traumatic and painful wound model for experimental studies would be difficult to justify ethically [2]. We retrospectively analyzed a case series of accidental wounds commonly found in equine veterinary practice. ...
Reasons for performing study: Because we used a different innovative protocol for treating equine traumatic wounds, it was decided to analyse retrospectively all the cases treated during the years 2005-2012. Objective: Evaluate the healing performances of traumatic horse wounds, either presenting or not with exuberant granulation tissue (EGT) or exposed bone, using an innovative plant-derived wound dressing and restricting the systemic antibiotic administration only to the first week after trauma. Methods: A retrospective analysis was conducted of all horses (n = 57) presenting with accidental wounds and treated with a plant-derived wound dressing. Classification of Wounds using COW score (Simple Wounds –SW- or Wounds presenting with Exuberant Granulation Tissue – EGT-W), Time To Heal (days), Epithelialisation Rate (cm/days), Health Of Wounds score, Time of First Epithelium appearance (TFE), Cosmetic Aspect of the final Scar (CAS), ease of handling, pain and complications were recorded and evaluated. Results: COW score determined 32 Simple Wounds (SW) with mean size varying from 12,72±6.48 cm2 (< 25 cm2), 50,76± 14,20 cm2 (25 and 100 cm2) to 310,023±132,(> 100cm2) and 25 EGT-Wounds (EGT-W) with mean size varying from 12,90±4,51cm2 (<25 cm2) to 62,76±26,55 cm2 (25 and 100 cm2). The SW healed faster than the EGT-W showing significant differences in the evaluated parameters (58,06±39,44 vs 79±54,32 days) (SW=0,14±0,06 vs EGT-W 0,0742±0,0342 cm/day) and in the TFE (of 7 vs of 18 days). CAS showed no significant differences between SW and EGT-W both presenting high quality of final scar. The dressing was able to keep the EGT formation under control without using surgical resection. Conclusions: This retrospective non-controlled analysis confirmed that equine wound complicated by the EGT have a lower healing performance but the EGT formation can be kept under control with a high quality of final scar. The treatment is simple to use and safe; it enables to reduce the intake of antibiotic and consequently limiting the risk of onset of antibiotic/antimicrobial resistance.
... Our aim, using this model, was to try and create a wound environment that more closely represented naturally occurring wounds compared with previous models where wounds were created surgically under aseptic conditions. [18][19][20][21][22][23] Our hypothesis was that manuka honey gel would be as effective as pure manuka honey in minimizing wound retraction, and longer term treatment with manuka honey gel would reduce the overall time to healing. We further hypothesized that treatment with manuka honey would enhance wound healing in wounds contaminated with feces compared with untreated wounds. ...
... Extended application of bandages has been shown to alter the healing pattern of wounds and lead to dysregulated fibroplasia and production of exuberant granulation tissue. 20 Manuka honey gel is more suitable for application to wounds that are not bandaged or cannot be bandaged, making it a more attractive topical therapeutic agent than pure manuka honey. ...
Objectives:
To compare the effects of manuka honey and manuka honey gel on second intention healing of noncontaminated distal limb wounds and those contaminated with feces.
Study design:
Experimental study.
Animals:
Standardbred horses (n = 10).
Methods:
Five full-thickness wounds (2 × 2 cm) were created on both metacarpi. Wounds on 1 forelimb were covered with horse feces for 24 hours. Wounds on the contralateral limb were left uncontaminated. Wounds were assigned to the following 5 different treatments: manuka honey, manuka honey gel or gel applied for 12 days, manuka honey gel applied throughout healing and untreated control. Wound area was measured on day 1 then weekly until day 42 and time to complete healing was recorded.
Results:
Wounds treated with manuka honey gel throughout healing healed faster than all other wounds (P < .05). Wounds treated with manuka honey and manuka honey gel for 12 days healed faster than gel control and untreated control wounds (P < .05). Wounds treated with manuka honey and manuka honey gel for 12 days and throughout healing were smaller than gel control and untreated control wounds until day 35 (P < .05). Wounds contaminated with feces had greater retraction for 7 days, but healed faster than noncontaminated wounds (P < .05).
Conclusions:
Treatment of wounds with manuka honey and manuka honey gel reduced wound retraction and overall healing time compared with gel and untreated control wounds.
... Digital imaging and computer aided analysis is based on the concurrent visibility of distance markers on wound images for calibration purposes and calculation of area measurements from image tracings. In veterinary studies wound parameters are typically assessed using methods of digital image analysis [6][7][8]. Although 2D techniques allow quantification of epithelialisation and contraction of a healing wound [6], they do not capture the specific characteristics of a granulation bed, such as the amount or quality of tissue formed, for which the use of ordinal and verbal grading scales has been required [7,8]. ...
... In veterinary studies wound parameters are typically assessed using methods of digital image analysis [6][7][8]. Although 2D techniques allow quantification of epithelialisation and contraction of a healing wound [6], they do not capture the specific characteristics of a granulation bed, such as the amount or quality of tissue formed, for which the use of ordinal and verbal grading scales has been required [7,8]. ...
Reasons for performing study: Methods of 3D wound imaging in man play an important role in monitoring of healing and determination of the prognosis. Standard photographic assessments in equine wound management consist of 2D analyses, which provide little quantitative information on the wound bed.
Hypotheses: 3D imaging of equine wounds is feasible using principles of stereophotogrammetry. 3D measurements differ significantly and are more precise than results with standard 2D assessments.
Methods: Repeated specialised photographic imaging of 4 clinical wounds left to heal by second intention was performed. The intraoperator variability in measurements due to imaging and 3D processing was compared to that of a standard 2D technique using descriptive statistics and multivariate repeated measures ANOVA.
Results: Using a custom made imaging system, 3D analyses were successfully performed. Area and circumference measurements were significantly different between imaging modalities. The intraoperator variability of 3D measurements was up to 2.8 times less than that of 2D results. On average, the maximum discrepancy between repeated measurements was 5.8% of the mean for 3D and 17.3% of the mean for 2D assessments.
Conclusions: The intraoperator repeatability of 3D wound measurements based on principles of stereophotogrammetry is significantly increased compared to that of a standard 2D photographic technique indicating it may be a useful diagnostic and monitoring tool.
Potential relevance: The equine granulation bed plays an important role in equine wound healing. When compared to 2D analyses 3D monitoring of the equine wound bed allows superior quantitative characterisation, contributing to clinical and experimental investigations by offering potential new parameters.
... The factors that affect the healing of wounds in rabbits include contraction of wound surface area, its epithelization process, granulation tissue formation, and contamination. Any hindrance in wound healing process not only delays the wound healing process but may increase the chances of infection (Dart et al., 2009). Deficiency of deep supportive tissue, more bony prominence, and frequent joint motion cause a delay in the healing of wounds because of the extended preparatory phase (Celeste et al., 2011). ...
Nanotechnology has revolutionized medicine, with a focus on green nanoparticle production that is
both friendly to the environment and cost effective. Biogenic nanoparticles have demonstrated great
potential in wound healing, especially through nanotechnology drug delivery systems such as
micelles, nanoparticles, nanoemulsions, and liposomes. These systems improve wound healing by
lowering medication cytotoxicity, increasing skin penetration, and providing antimicrobial
protection. Zinc oxide (ZnO) nanoparticles are particularly useful due to their antibacterial and
anticancer characteristics. This study addressed the wound healing effects of ZnO nanoparticles in
18 rabbits separated into three groups: control (normal saline), ZnO nanoparticles, and ZnO
ointments. Wound contraction size, hematological, and histology were evaluated on days 0, 5, 10,
and 15. The results showed that ZnO nanoparticles significantly increased wound contraction and
histological parameters such as angiogenesis and re-epithelization when compared to the control and
ZnO ointment groups. The hematological study revealed no infection or harm. In conclusion, ZnO
nanoparticles have better healing and therapeutic properties than ZnO ointment.
... In their study, Berry II and Sullins [18] noted that all wounds treated with bandages exhibited exuberant granulation tissue, whereas none of the un-bandaged wounds showed signs of EGT development. Dart et al. [29] also observed that open wounds began to contract earlier and went through a rapid and more intense period of contraction than bandaged wounds, which produced excessive granulation tissue that required regular resections. Bandaged limb wounds, in addition to developing EGT and showing delayed healing, also had significantly higher biofilm grades compared to un-bandaged limb wounds [45]. ...
Equine skin wound treatment continues to be a challenge for veterinarians. Despite being a frequent practice, it remains difficult to choose an evidence-based treatment protocol. This study aimed to comprehensively explore the literature and provide a scoping review of therapeutic strategies for equine skin wounds and identify knowledge gaps and opportunities for future research. This review was conducted using specific criteria to select literature that described methods to manage second intention wound healing. After removing duplicates and screening papers for suitability, 81 manuscripts were included for data extraction. Of these, 59 articles were experimental studies, 10 were case reports, 9 were case series, and 3 were clinical studies. The most frequent wound location was the distal limbs. Macroscopic assessment was the main tool used to evaluate treatment effectiveness. All of the case reports, case series, and clinical studies reported positive outcomes with regard to the treatment used, while only 36% of the experimental studies found significant healing improvement in treated wounds compared to control groups. It was found that there are many treatments that have exhibited controversial results, and there exists a lack of evidence for the adoption of specific treatment protocols.
... Equine wounds, especially in the limbs, can be challenging to heal due to factors such as wound surface area contraction, epithelization, granulation tissue formation, and contamination. Hindrances in the wound healing process can lead to delayed healing and an increased risk of infection (Dart et al. 2009). ...
The domesticated donkey, derived from the African wild ass, has played a crucial role in human history for over 5,000 years, serving as a working and pack animal. However, donkeys often suffer from skin wounds and injuries due to various factors, including equipment use, road accidents, and lack of veterinary care. Wound healing is a complex process involving inflammation, proliferation, and maturation phases, with impaired cell proliferation potentially delaying healing. Equines, including donkeys, are particularly susceptible to traumatic skin wounds, with limb wounds healing more slowly due to factors such as tissue loss, contamination, and excessive skin tension. In such cases, wound healing by second intention is common but can lead to complications. Chitosan, a biopolymer derived from the shells of crustaceans, has shown promise in promoting wound healing. It helps with tissue granulation, collagen deposition, and tissue regeneration, while also preventing wound contamination and maintaining a sterile environment. Honey, with its antimicrobial, anti-inflammatory, and antioxidant properties, is another natural remedy that accelerates wound healing and is often used in combination with chitosan for optimal results. This biologically-based approaches hold potential for improving the healing of donkey wounds and preventing infections, offering safer and more effective alternatives to traditional wound care.
... Poor prognosis, unsatisfactory cosmetics, prolonged wound healing, and in horses' lower extremities lead to elevated risks of the increased motion wound area, lack of soft tissue support, lack of blood supply, as well as bacterial and infection contamination. Consequently, the wounds in the lower extremity are considered crippling as well as life-threatening to horses [22]. ...
Aim
The current research aimed to evaluate the potential effect of adding platelet-rich fibrin (PRF) to the decellularized bovine pericardium (DBP) on the distal limb of donkeys’ full-thickness cutaneous wounds healing (Equus asinus).
Materials and Methods
Healthy male donkeys (n = 12) were used in this study. Under general anesthesia, 6 cm2 full-thickness incisions were made on the middle dorsolateral surface of both forelimbs’ metacarpi. The left forelimbs were control wounds, while the right wounds were treated with PRF/DBP. Control wounds were bandaged with a standard dressing after saline irrigation and were evaluated at days 4, 7, 10, 13, 16, 19, 22, 25, and 28 post-wounding. PRF/DBP-treated wounds were dressed with a combination of PRF/DBP at the first, second, and third weeks post-wounding. Clinical and histopathological examinations of the wounds were performed to assess the healing process. Additionally, the immunohistochemical evaluation and gene expression profiles of myofibroblastic and angiogenic genes (transforming growth factor-β1, vascular endothelial growth factor-A, fibroblast growth factor 7 (FGF-7), and collagen type 3α1) were analyzed.
Results
PRF/DBP wounds had a significantly faster healing process (61.3 ± 2.6 days) than control wounds (90.3 ± 1.4 days) (p < 0.05). The immunohistochemical examination and gene expression profile revealed significant enrichment in PRF/DBP wounds compared to control wounds.
Conclusion
PRF/DBP dressing can be considered a natural and cost-effective biomaterial for enhancing the recovery of donkeys’ distal limb injuries.
... Many factors affect the healing of equine leg wounds: wound expansion, contraction, epithelization process, granulation tissue formation, and contamination (Dart et al. 2009). Moreover, bony prominence in this area, deep supportive tissue deficiency, and higher joint motion give equine distal tissue, along with the new formation organized collagen fibers. ...
This research was performed to determine the impact of repeated topical dressing with acellular bovine pericardium (ABP) on healing distal limb wounds in donkeys. Twelve male clinically healthy donkeys were subjected to general anesthesia, and full-thickness wounds of six cm² (2 × 3 cm) were created on the middle dorsolateral surface of the metacarpi. Two defects were made on each donkey’s forelimbs; the right limb was considered a control wound, and the left one was considered a treated wound. Moreover, the control wounds were irrigated with saline every three days postoperatively and bandaged with a standard dressing. The treated wounds were covered with ABP dressings. The ABP dressing was reapplied thrice at 7-, 14- and 21-days post-wound induction. In addition, the wound healing process was monitored clinically, histopathologically, and immunohistochemically of tissue as growth factor-β1, epidermal growth factor receptor, and vascular endothelial growth factor. Besides, the gene expression profile of angiogenic and myofibroblastic genes was applied as vascular endothelial growth factor-A, collagen type 3α1, fibroblast growth factor 7, and the transforming growth factor-β1.
The results revealed that the wounds treated with ABP healed more quickly than the control wounds. Additionally, the mean days required for healing were significantly shorter in the ABP-treated wounds (p < 0.05; 69.5 ± 1.6) compared to control wounds (86.3 ± 3). Furthermore, immunohistochemical and gene expression analyses were significantly improved in ABP wounds than in control wounds. In conclusion, ABP is considered a natural biomaterial and promotes the healing of distal limb wounds in donkeys if applied weekly during the first three-week post-wound induction.
... The survey results confirm that limb wounds can be more challenging and labour intensive to manage, and often develop complications such as wound infection and formation of exuberant granulation tissue, that will prolong treatment, increase its cost and worsen the prognosis. 13 This study confirms previous reports that wounds are a common condition encountered by veterinarians treating horses. 6,8,9 Consequently, the assessment and management of wounds in horses should be an important learning outcome for veterinary students intending to pursue equine or mixed practice. ...
Objective: To survey Australian veterinarians on the frequency and features of wounds encountered in their equine patients, duration and costs of treatment, as well as expected outcomes. Methods: A survey was sent to members of Equine Veterinarians Australia. Questions probed the demographics of respondents, the number of wound-related cases in relation to the total equine caseload, the type and location of wounds, the frequency, duration and cost of treatment, and the outcome of therapy. Results: The median number of equine cases was 40/month and of these, 9 were wound-related (22.5%). Sixty per cent of the respondents estimated that their clients frequently treated wounds incurred by their horse without consulting a veterinarian. Wounds on the distal limb involving only the skin, or the skin and deeper structures, were reported to be the most frequently encountered. Wounds on the distal limb required longer treatment incurred a greater cost and were the most likely to develop complications. Wounds/trauma ranked second, after colic, as the most common cause of death or euthanasia. Conclusions and clinical relevance: The results of the survey indicate that wounds are costly to treat and represent a welfare issue for the Australian equine industry. These results suggest that a greater effort should be devoted to the education of horse owners about wound prevention and management and that more research should be directed to wound healing in an effort to improve patient outcomes
... Extract application resulted in relieving edema and inflammation around the wounds, disappearance of infection, and observable decreased wound surface. After extract application, the wounds were not covered with bandages due to the authors of [74] reporting that the bandaged wound took a longer time to heel than unbandaged wounds. The application of the extracts absorbing exudate, keeping the wound moist, which helps epithelization, prevent contamination of wound from flies due to presence of Oxiranepent Hexadecanoic Anoic Acid, 3-UndecyL-, Methyl Ester, Trans, which has pesticide activity as recorded by [44]. ...
Various herbal compounds are used for medical purposes due to their safety, as there are no or minimal side effects. This study was performed to assess the wound healing and antioxidant activities of ethyl acetate (EtOAc) and methanolic extract (MeoH) of Solenostemma arghel (S. arghel). Their antifungal activities were also evaluated against isolated swabs of equine wounds. They underwent GC-MS analysis for the characterization of both extracts. For wound healing evaluation, forty-five male albino rats were divided into three groups; the control group was treated with normal saline, and the other two groups were treated with S. arghel EtOAc and MeoH extract gels, respectively. The wounds were examined clinicopathologically and immunohistochemistry on the 3rd, 7th, and 14th days post-wounding. GC-Ms analysis of S. arghel recorded fifty-one volatile organic compounds (VOCs) within EtOAc extraction and thirty VOCs in MeoH extract. VOCs represented in EtOAc extract showed higher antioxidant activity and better and faster wound healing than VOCs of MeOH extract. The treated groups showed improved wound healing clinically and pathologically in comparison with the control group as they decreased the wound surface area (WSA) and percent (WSA%) and increased the wound contraction percent (WC%), epithelization, fibroblast proliferation with neovascularization, and reduced the inflammatory reaction. Moreover, the treated groups showed higher expression of vascular endothelial growth factor (VEGF) compared with the control. The EtOAc extract showed higher antifungal activity against Penicillium funiculosum, P. jensenii, M. cinctum, and Candida albicans, which were isolated from infected clinical equine wounds, than MeOH extract. The treated groups showed improved wound healing clinically and pathologically in comparison with the control group as they decreased the wound surface area (WSA) and percent (WSA%) and increased the wound contraction percent (WC%), epithelization, fibroblast proliferation with neovascularization, and reduced the inflammatory reaction. Moreover, the treated groups showed higher expression of vascular endothelial growth factor (VEGF) compared with the control. Additionally, the two extract gels showed promising healing of equine wounds. In conclusion, the study recommended the use of S. arghel EtOAc extract as it was proven to promote wound healing compared with MeoH extract. View Full-Text
... Then, 12 h prior to surgery, a 14-gauge IV catheter was placed aseptically in the jugular vein and feed withheld for 8 h prior to induction of anesthesia. As the created wounds were objectively small and discomfort relatively minor, the wounds were bandaged only for recovery then left unbandaged to not influence exuberant granulation tissue formation [1,27]. Similarly, no analgesics were administered to not affect inflammation associated with healing [28,29]. ...
Limb wounds are common in horses and often develop complications. Intravenous multipotent mesenchymal stromal cell (MSC) therapy is promising but has risks associated with intravenous administration and unknown potential to improve cutaneous wound healing. The objectives were to determine the clinical safety of administering large numbers of allogeneic cord blood-derived MSCs intravenously, and if therapy causes clinically adverse reactions, accelerates wound closure, improves histologic healing, and alters mRNA expression of common wound cytokines. Wounds were created on the metacarpus of 12 horses. Treatment horses were administered 1.51–2.46 × 108 cells suspended in 50% HypoThermosol FRS, and control horses were administered 50% HypoThermosol FRS alone. Epithelialization, contraction, and wound closure rates were determined using planimetric analysis. Wounds were biopsied and evaluated for histologic healing characteristics and cytokine mRNA expression. Days until wound closure was also determined. The results indicate that 3/6 of treatment horses and 1/6 of control horses experienced minor transient reactions. Treatment did not accelerate wound closure or improve histologic healing. Treatment decreased wound size and decreased all measured cytokines except transforming growth factor-β3. MSC intravenous therapy has the potential to decrease limb wound size; however, further work is needed to understand the clinical relevance of adverse reactions.
... Chronic wounds, particularly those located on the distal limbs, represent a substantial treatment and management challenge for equine practitioners. 1 Although there are numerous available dressings and topical therapies, reports of efficacy in experimental studies are mixed, with promising intermediate outcomes having been reported, but ultimately little improvement in overall time to wound healing. [2][3][4] Cost is also a concern with many existing products, especially for long-term management. Equine amnion may offer one solution for a cost-effective biological wound dressing, but evidence-based recommendations for its use in the field are scarce. ...
Objective
To determine the influence of tissue preparation and long‐term storage methods on structural integrity and risk of bacterial contamination of equine amnion.
Study design
Prospective experimental investigation
Sample population
Amniotic membranes from 8 healthy mares (n = 440 tested samples).
Methods
Samples for baseline bacteriology and histology were taken after removal of debris. The remaining tissue was divided and processed with 0.05% chlorhexidine or 2% iodine/0.25% acetic acid. Processed amnion samples were assigned to 1 of 9 combinations of storage media (saline, chlorhexidine, acetic acid) and temperature (4 °C, −20 °C, −80 °C). Samples were submitted for quantitative bacteriology and histopathology at 1 week, 4 weeks, and 3, 6, 9, and 12 months.
Results
Baseline bacterial levels ranged from <200 to > 150 000 colony‐forming units (cfu)/mL. None of the potentially pathogenic bacteria in baseline samples were subsequently cultured throughout the study. Nonpathogenic bacteria (median 20 cfu/mL), most commonly Bacillus sp, were cultured sporadically across storage conditions. Tissue architecture was minimally affected histologically by processing protocol, storage temperature, or storage duration.
Conclusion
The 2 processing protocols tested here resulted in minimal bacterial contamination or loss of structural integrity of equine amnion stored for up to 12 months at 4 °C, −20 °C, or −80 °C.
Clinical significance
Amnion collected during the foaling season may be stored for up to 12 months without significant bacterial contamination or structural alterations.
... Although a moist wound healing environment associated with the use of dressings is advocated in other species to manage wounds healing by secondary intention, this approach is not always appropriate in the horse because of its tendency to develop EGT [9][10][11]. The clinical observation that bandaging can induce excessive wound granulation led to development of an experimental model of equine EGT [12]. ...
Bandaging of limb wounds in horses leads to formation of exuberant granulation tissue (EGT) that retards healing due to protracted inflammation, aberrant vascularisation and delayed epithelialisation. EGT is not observed if wounds are left undressed or when wounds are on the body. A previous study showed that short-term administration of proteins derived from orf virus dampened inflammation and promoted epithelialisation of open wounds in horses. Here, we investigated the impact of orf virus interleukin-10 and vascular endothelial growth factor-E on the development and resolution of EGT. Excisional wounds were created on the forelimb of four horses, and bandages were maintained until full healing to induce EGT formation. Matching body wounds were created to ensure EGT was limited to the limb, and to differentiate the effects of the viral proteins on normal healing and on EGT formation. Viral proteins or the hydrogel vehicle control were administered topically to site-matched wounds at day 1, with repeat administration at day 8. Wound healing and EGT formation were monitored macroscopically. Wound margin samples were harvested at 2, 7 and 14 days, and at full healing, with histology used to observe epithelialisation, immunofluorescence used to detect inflammatory cells, angiogenesis and cell death, and qPCR to measure expression of genes regulating inflammation and angiogenesis. Limb wounds developed EGT, and exhibited slower healing than body wounds. Viral protein treatment did not accelerate healing at either location nor limit EGT formation in limb wounds. Treatment of limb wounds did however increase epithelialisation and angiogenesis, without dampening inflammatory cell infiltration or gene expression. The healed wounds also had less occlusion and death of blood vessels and fewer epidermal rete ridges following viral protein treatment. These findings indicate that the viral protein treatment does not suppress wound inflammation or EGT formation, but does promote vascular and epidermal repair and EGT resolution.
... In humans, desiccation has recently been described to accelerate wound healing by a decrease in biofilm burden with subsequent reduction of inflammation in the wound bed (Park et al., 2016), and desiccation may thus be part of the explanation for the lower biofilm grades observed in unbandaged limb and shoulder wounds. The non-adhesive gauze dressing used in the present study has been used in several previous studies to provoke experimental formation of EGT and retard healing in equine limb wounds (Celeste et al., 2013;Dart et al., 2009;Sørensen et al., 2014;Theoret et al., 2002). The present study is the first to describe the significantly larger biofilm burdens in limb wounds dressed with sterile nonadhesive gauze than in un-bandaged wounds. ...
In humans, biofilm is a well-known cause of delayed healing and low-grade inflammation of chronic wounds. In horses, biofilm formation in wounds has been studied to a very limited degree.
The objective of this study was thus to investigate the occurrence of biofilm in equine experimental wounds healing by secondary intention.
Tissue biopsies from non-contaminated, experimental excisional shoulder and limb wounds were obtained on day 1-2, day 7-10 and day 14-15 post-wounding. Limb wounds were either un-bandaged or bandaged to induce exuberant granulation tissue (EGT) formation and thereby impaired healing. Presence of biofilm in tissue biopsies was assessed by peptide nucleic acid fluorescence in situ hybridization (PNA FISH) and confocal laser scanning microscopy (CLSM).
Bandaged limb wounds developed EGT and displayed delayed healing, while shoulder and un-bandaged limb wounds healed normally. Biofilm was detected in limb wounds only. At day 14-15 biofilm was significantly more prevalent in bandaged limb wounds than in un-bandaged limb wounds (P = 0.003). Further, bandaged limb wounds had a statistically significant increase in biofilm burden from day 7-10 to day 14-15 (P = 0.009).
The finding that biofilm was most prevalent in bandaged limb wounds with EGT formation suggests that biofilm may be linked to delayed wound healing in horses, as has been observed in humans. The inability to clear bacteria could be related to hypoxia and low-grade inflammation in the EGT, but the interaction between biofilm forming bacteria and wound healing in horses needs further elucidation.
... Delayed healing of lower limb lesions and excessive granulation tissue formation following the use of bandages has been reported in equines. 36,37 Although controversial, some have suggested that these observations may be a consequence of reduced oxygen tension and low pH at the lesion surface beneath the bandage. 38 In contrast, others have shown that oxygen supplementation under metatarsal bandages failed to result in improved wound healing. ...
Abstract: Lameness is a leading cause of welfare and culling issues in cattle, with claw lesions accounting for the majority of these issues. Although the treatment of claw lesions in cattle is a daily activity for hoof trimmers, veterinarians, and livestock producers, there is surprisingly little information in the peer-reviewed literature on which to base strong evidence-based conclusions. As a consequence, many treatment modalities used are empirical and, in some cases, may be counterproductive to rapid lesion healing. Furthermore, many of these empirical treatment modalities fail to fully consider the underlying pathogenesis of the disease process and the implications that it has on lesion healing. For example, sole ulcers are largely a consequence of metabolic disorders and mechanical overloading. Therapeutic interventions that fail to address the weight-bearing issues are unlikely to be successful. Likewise, white line disease is believed to be predisposed by rumen acidosis and laminitis, and interventions need to include in them appropriate measures to prevent further cases through nutritional management. The goal of this review paper is to review the pathogenesis of claw lesions in the context of the published literature and allow the reader to arrive at rational treatment interventions based on the best available information. The use of an orthopedic block applied to the healthy claw of a lame foot, judicious use of bandage or wrap, careful selection of parenteral or topical therapy, and a treatment protocol to manage pain and promote recovery are key components of responsible management of lameness disorders in cattle.
... Although the moist wound healing environment associated with the use of occlusive dressings is advocated in other species, this approach is not always appropriate in the horse because of its tendency to develop EGT. [15][16][17][18] A wide variety of wound dressings, ranging from passive to interactive/bioactive products that contribute to the healing process, have been designed specifically for horses and are commercially available. 19 The choice of treatment depends on, among other factors, the phase of healing (inflammatory, proliferative, and remodeling) and avoidance of occlusion. ...
Impaired wound healing represents an enormous clinical and financial problem for companion animals and humans alike. Unfortunately, most models used to study healing rely on rodents, which have significant differences in the healing and scarring process and rarely develop complications. In order to better simulate impaired healing, the model should strive to reproduce the natural processes of healing and delayed healing. Wounds on the limbs of horses display similarities to wounds in humans in their epithelialization/contraction ratio, genetic influence as well as dysregulated cytokine profile and the spontaneous development of fibroproliferative disorders. Veterinarians have access to advanced wound therapies that are often identical to those provided to human patients. Wound research in large animals has resulted in new wound models as well as a better understanding of the physiology, immunology, and local environmental impact on both normal and aberrant wound healing. One such model reproduces the naturally occurring fibroproliferative disorder of horses known as exuberant granulation tissue. Comparisons between the normally healing and impaired wounds provide insight into the repair process and can facilitate product development. A better understanding of the wound healing physiopathology based on clinically accurate animal models should lead to the development of novel therapies thereby improving outcomes in both human and veterinary patients.
Objective:
To assess the efficacy of an equine-origin liquid amnion allograft (ELAA) derived from both amniotic fluid and amniotic membrane on the healing time of experimentally induced distal limb wounds in horses.
Animals:
8 adult horses.
Procedures:
On day 0, horses were anesthetized and a 2.5 X 2.5-cm, full-thickness skin wound was created on the dorsal aspect of each metacarpus and bandaged. On day 9, wound margins were injected with ELAA (treatment) or 0.9% NaCl (control). Bandages were changed at specific intervals through day 91 and, on each occasion, wounds were photographed to allow calculation of wound area. Exuberant granulation tissue was resected, if present. Wounds were deemed healed when completely epithelialized. Mean wound area was compared between groups throughout the study period.
Results:
Only 1 wound (control) remained unhealed at day 91. No difference was found between the treatment and control groups in either wound area over time (P = 1.0) or time for wounds to reduce in size by 95% (P = .2) Exuberant granulation tissue required resection twice (1 control wound and 1 treatment wound).
Clinical relevance:
In this model, a single treatment with ELAA administered locally by SC injection did not accelerate distal limb wound healing in horses. However, it is possible that naturally occurring, chronic, or nonhealing wounds would respond differently.
Excessive or exuberant granulation tissue (EGT) is not a direct surgical complication but a complication of wounds healing by second intention. Second intention healing is seen more often in traumatic wounds than in surgical wounds. However, after certain surgical procedures, for example tumor resection, a resultant tissue deficit or development of incisional dehiscence may require the site to be left to heal by second intention. Besides EGT being a complication, the surgical treatment of EGT can lead to complications. This chapter presents the definition, risk factors, pathogenesis, prevention, diagnosis, treatment, and expected outcome of the complications associated with EGT. The complications covered include EGT formation, excessive hemorrhage after EGT excision, and damage to important structures during EGT excision.
Distal limb wounds are common injuries sustained by horses and their healing is fraught with complications due to equine anatomy, prevalence of infection, and challenges associated with wound management. Gallium is a semi-metallic element that has been shown to possess antimicrobial properties and aid in wound healing in various preclinical models. The effects of Gallium have not been studied in equine wound healing. Therefore, the objective of this study was to compare healing rates between gallium-treated and untreated wounds of equine distal limbs and to demonstrate the antimicrobial effects of gallium on wounds inoculated with S. aureus. Using an established model of equine wound healing we demonstrated beneficial effects of 0.5% topical gallium maltolate on equine wound healing. Specifically we documented reduced healing times, reduced bioburden, and reduced formation of exuberant granulation tissue in wounds treated with gallium maltolate as compared with untreated wounds. Gallium appeared to exert its beneficial effects via its well-described antimicrobial actions as well as by altering the expression of specific genes known to be involved in wound healing of horses and other animals. Specifically, gallium maltolate appeared to increase expression of transforming growth factor-β in both infected and un-infected wounds. Further work is needed to document the effects of gallium on naturally occurring equine wounds and to compare the effects of gallium with other wound treatment options. These data, however, suggest that gallium may be an attractive and novel means of improving equine distal limb wound healing.
The protein content of amnion is thought to be the primary contributor to its efficacy as a biological dressing for wounds. Protein elution into antibiotic processing media has been reported, but the effect of antiseptic-based processing methods is unknown. Amniotic membranes were collected from eight healthy mares. Samples were collected after removal of gross debris. Tissues were subsequently divided and processed with either 0.05% chlorhexidine or 2% iodine/0.25% acetic acid. After protein extraction and trypsin digestion, the proteins were labeled with 8-plex iTRAQ tags, combined, and analyzed by high-resolution liquid chromatography-mass spectrometry. The MaxQuant-Perseus software suite was used to identify and quantify sample proteins, with functional annotation performed in PANTHER. There were 220 unique proteins identified, of which 144 were found in all individuals and across all conditions, several with a known role in wound healing. Contrary to expectations, processing did not significantly alter the protein content of the amnion tissue. Limitations include the small sample size and single time point. These results suggest that either processing method is acceptable for use in the preparation of equine amnion dressings. The role of expressed proteins in the biological activity of amnion dressings remains to be elucidated.
Significance: Cutaneous wounds are a major problem in both human and equine medicine. The economic cost of treating skin wounds and related complications in humans and horses is high, and in both species, particular types of chronic wounds do not respond well to current therapies, leading to suffering and morbidity. Recent Advances: Conventional methods for the treatment of cutaneous wounds are generic and have not changed significantly in decades. However, as more is learned about the mechanisms involved in normal skin wound healing, and how failure of these processes leads to chronic nonhealing wounds, novel therapies targeting the specific pathologies of hard-to-heal wounds are being developed and evaluated. Critical Issues: Physiologically relevant animal models are needed to (1) study the mechanisms involved in normal and impaired skin wound healing and (2) test newly developed therapies. Future Directions: Similarities in normal wound healing in humans and horses, and the natural development of distinct types of hard-to-heal chronic wounds in both species, make the horse a physiologically relevant model for the study of mechanisms involved in wound repair. Horses are also well-suited models to test novel therapies. In addition, studies in horses have the potential to benefit veterinary, as well as human medicine.
Equine distal limb wounds may be left to heal by second intention, a potentially slow method of healing. This study evaluated the effect of maltodextrin on second-intention healing of full-thickness equine distal limb wounds. A 4 × 4 cm full-thickness wound was created on the dorsal aspect of the metacarpus of each front limb in 8 horses. Wounds were randomly assigned to the control group (no treatment) or treatment group (maltodextrin applied daily starting one day after wound creation). Wounds were bandaged until the wound bed was filled with granulation tissue, then discontinued. Amount and quality of granulation tissue, amount of epithelialization, and presence of exudate were recorded until wounds were completely epithelialized by an investigator blinded to treatment. Wounds were photographed at each time point and wound area was determined using computer software. A repeated measures two-way ANOVA was performed to analyze wound area data over time. There was no difference in measured parameters over time or at any single time point between treated and control wounds. Treatment was discontinued on day 18 due to persistence of granulation tissue above the level of the epithelium in treated wounds. Treatment of open wounds with maltodextrin on distal limbs of horses promoted persistent excessive granulation tissue formation during day 12–17 following wound creation but did not affect wound healing after its discontinuation. The use of maltodextrin during the appropriate phases of wound healing may reduce initial wound enlargement and could potentially be used to promote granulation tissue formation.
Distal limb wounds in horses heal substantially different than trunk wounds, commonly resulting in exuberant granulation tissue and exposed and sequestered bone. Surgical intervention of severe rectovaginal lacerations in the mare should be delayed until the tissues have heeled and scar tissue has remodeled. Wounds resulting in severe hemorrhage require appropriate emergent fluid therapy and potentially transfusion therapy.
Myriads of wound-care products are on the market, and making the right choice for a specific wound can be complex, especially because the scientific literature on wound-care products in horses is sparse. To select the best possible dressing, the veterinarian must decide which material is needed to enhance healing. The clinician must then determine if antimicrobial therapy is required. Several antibacterial compounds are available for topical use and are often more effective than systemically administered antibiotics in the management of severe contamination, critical colonization, or infection. To serve the requirements of specific wounds, several combinations of antimicrobial drugs and dressings are available. The wound milieu changes as healing progresses and so do the requirements for dressings. Continued assessment, based on a thorough clinical examination and sound knowledge of the healing process, is indicated, therefore, to maintain an optimal environment for healing.
The formation of exuberant granulation tissue (EGT) is a frequent complication of wounds healing by second intention on the limbs of horses. Among the large number of contributing factors, chronic inflammation is foremost and often goes unrecognized because of the mild signs it elicits. The stimulus for formation of EGT is reduced when prevention and treatment of chronic inflammation are combined with excision of the protruding granulation tissue. This approach allows a smooth transition from fibroplasia to wound contraction and epithelialization and usually obviates the recurrence of EGT. The topical application of a corticosteroid, used in a precise and controlled manner, and the use of silicone sheet dressings, as well as skin grafting, are valuable in preventing the formation of EGT. In cases where EGT is already present, excision of the protruding granulation tissue is the treatment of choice.
Bandages and splints or casts are an essential component of wound management and, when used properly, can greatly aid healing. Improper application, however, may impede healing and be detrimental to the well-being or athletic future of the horse. Many different types of bandage materials exist and are reviewed in Chapter 6. This chapter is devoted to the principles and techniques of bandaging and casting. Splinting is discussed along with casting because either approach may be used when immobilization is required to support wound healing. Various techniques to improve the application and maintenance of bandages, splints, and casts, as well as to manage complications arising from their use, are discussed.
The aim of wound management is to optimize healing in an effort to return the horse to its previous function as rapidly as possible, while respecting the financial constraints of the owner. Infection, with its associated excessive or inappropriate inflammation, is the single most likely cause of delayed healing of wounds healing by second intention. Effective wound preparation, exploration, cleansing via irrigation, and debridement are central to reducing the incidence of infection and promoting uncomplicated healing of accidental wounds. Antimicrobial drugs should be used only when there is clinical evidence of infection or when development of an infection would be life-threatening or career-ending for the patient. Although empiric broad-spectrum antimicrobial therapy may be used initially, definitive selection of antimicrobial drugs should be based on the results of bacterial culture and sensitivity testing of isolates. The use of antimicrobial drugs in surgical wounds should never replace aseptic and atraumatic surgical technique. Where there is evidence of formation of biofilm, repeat debridement and topical administration of antimicrobial drugs should be central to any treatment plan.
Objective:
To investigate the effect of 66% Manuka honey gel on the concentrations of transforming growth factor (TGF)-β1 and TGF-β3, bacterial counts and histomorphology during healing of contaminated equine distal limb wounds.
Methods:
In this experimental study of 10 Standardbred horses, five full-thickness skin wounds (2 × 1.5 cm) were created on one metacarpus and six similar wounds were created on the contralateral metacarpus. Wounds were assigned to three groups: non-contaminated control wounds; contaminated control wounds; contaminated wounds treated daily with 1 mL Manuka honey gel topically for 10 days. For the contaminated wounds, faeces were applied for 24 h after wound creation. In five horses wounds were bandaged and in the other five horses wounds were left without a bandage. Biopsies were taken on days 1, 2, 7 and 10 after wounding to evaluate the effects of Manuka honey gel, wound contamination and bandaging on TGF-β1 and TGF-β3 concentrations, aerobic and anaerobic bacterial counts, and histomorphology.
Results:
Manuka honey gel had no significant effect on TGF-β1 and TGF-β3 concentrations or wound bacterial counts. Manuka honey gel decreased wound inflammation (days 7, 10), increased angiogenesis (days 2, 7, 10), increased fibrosis and collagen organisation (day 7) and increased epithelial hyperplasia (days 7, 10).
Conclusions:
Treatment with Manuka honey gel resulted in a more organised granulation tissue bed early in wound repair, which may contribute to enhanced healing of equine distal limb wounds.
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.ResultsThere 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.
In addition to the generic properties of honey, manuka honey has a nonperoxide antimicrobial activity largely attributed to methylglyoxal. Commercially, manuka honey is graded against a standard antiseptic, phenol, to provide a measure of antimicrobial activity referred to as the unique manuka factor (UMF). The higher the UMF, the greater the antimicrobial activity. However, more recently, there is evidence that manuka honey can also modulate the initial inflammatory response through activation of toll-like receptor 4 on monocytes to enhance production of cytokines important in tissue repair and regeneration. Recent studies investigating the effects of manuka honey on second intention healing of lower limb wounds in horses have shown that wounds treated with UMF 20 manuka honey retracted less and healed faster than untreated wounds. Using this wound healing model, the primary effects of manuka honey appeared to be associated with the modulation of the initial inflammatory reaction rather than its antimicrobial effects. Based on the current knowledge, treatment with manuka honey should be instituted as soon as possible after injury. Where bacterial contamination is substantial, manuka honey with a UMF ≥15 should be used. While bandages will improve the contact between the honey and the wound and may be indicated in the early stages of wound healing, prolonged bandaging may lead to the production of excessive granulation tissue. If topical treatment without a bandage is to be used, more honey is not necessarily better. Using a thin film combined with regular application, contact times may be optimised. Application 2–3 times daily to open wounds may improve efficacy. Manuka honey should be applied for at least 21 days after wounding but there may be beneficial effects if it is applied until wound healing is almost complete.
Wounds are of great concern in animals as they affect animal productivity and their treatment represents an economic burden to the owners particularly in developing countries. The present study investigated the beneficial role of a mixture of cod liver oil and honey in treatment of old wounds in equines. In which, 3 horses and 7 donkeys were admitted to the Veterinary Teaching Hospital at Assiut University, Assiut, Egypt with old wounds at the metacarpus (5 cases) and metatarsus (3 cases) and at the level of fetlock and carpal joints (one case each). Treatment of these wounds with cod liver oil/honey mixture markedly decreased their sizes and resulted in formation of a healthy scar after one month of treatment. To explain the mechanisms that underlie the effects of this mixture, 9 surgically-induced wounds at the metacarpus in 9 donkeys were treated with honey, cod liver oil or the mixture (3 wounds each) and compared with parallel untreated control wounds at the metatarsus. It was found that treatment of wounds with honey, cod liver oil and the mixture apparently decreased the size of wounds. Histopathological examination revealed that treated wounds with honey or cod liver oil showed complete epithelization over the wound areas. On the other hand, epithelization process was not complete in wounds treated with the mixture. Granulation tissue showed some variability between different treatments. Of which, wounds treated with the mixture showed a higher degree of maturity with increasing numbers of fibrocytes and parallel collagenous fibers. This could underlie the good results obtained in case studied wounds with the mixture. In conclusion, mixture of cod liver oil and honey is beneficial in treatment of old traumatized wounds in equine and this effect is primarily mediated by formation of healthy and mature scars. Cod liver oil or honey alone is beneficial for healing of recent and surgical wounds as they facilitate epithelization process.
Fibroblast growth factor (FGF) 9 is secreted by both mesothelial and epithelial cells, and plays important roles in organ development and wound healing via WNT/β-catenin signaling. The aim of this study was to evaluate FGF9 expression and FGF-WNT/β-catenin signaling during wound healing of the skin. We investigated FGF9 expression and FGF-WNT/β-catenin signaling after laser ablation of mouse skin and adult human skin, as well as in cultured normal human epidermal keratinocytes (NHEKs) upon stimulation with recombinant human (rh) FGF9 and rh-transforming growth factor (TGF)-β1. Our results demonstrated that laser ablation of both mouse skin and human skin leads to marked overexpression of FGF9 and FGF9 mRNA. Control NHEKs constitutively expressed FGF9, WNT7b, WNT2, and β-catenin, but did not show Snail or FGFR2 expression. We also found that FGF receptor (FGFR) 2 was significantly induced in NHEKs by rhFGF9 stimulation, and observed that FGFR2 expression was slightly upregulated on particular days during the wound healing process after ablative laser therapy. Both WNT7b and WNT2 showed upregulated protein expression during the laser-induced wound healing process in mouse skin; moreover, we discerned that the stimulatory effect of rhFGF9 and rhTGF-β1 activates WNT/β-catenin signaling via WNT7b in cultured NHEKs. Our data indicated that rhFGF9 and/or rhTGF-β1 upregulate FGFR2, WNT7b, and β-catenin, but not FGF9 and Snail; pretreatment with rh dickkopf-1 significantly inhibited the upregulation of FGFR2, WNT7b, and β-catenin. Our results suggested that FGF9 and FGF-WNT/β-catenin signaling may play important roles in ablative laser-induced wound healing processes.
As in other fibroproliferative disorders, hypoxia has been suggested to play a key role in the pathogenesis of exuberant granulation tissue (EGT). The purpose of this study was to investigate metabolism and blood flow locally in full-thickness wounds healing with (limb wounds) and without (body wounds) formation of EGT.Microdialysis was used to recover endogenous metabolites from the wounds, and laser Doppler flowmetry was used to measure blood flow. Measurements were performed before wounding and 1-28 days after wounding.Blood flow was consistently lower in limb wounds than in body wounds throughout the study period with no change over time. After wounding and throughout the study period theglucose concentration wassignificantly lower in limb wounds than in body woundswhereas the lactate level showed a significantly higher concentration in limb wounds. The lactate/glucose ratio displayed a significant difference between body and limb wounds.In conclusion, the metabolic disturbances may suggest inadequate oxygen supply during the wound healing process in equine limb wounds healing with EGT. This may be related to the inherently decreased perfusion in the wound bed of limb wounds.
The use of low-level microcurrents for accelerated wound healing is well documented. A case series was conducted to assess wound healing outcomes following the application of a wireless, current-generating bioelectric wound care device in 10 equines that presented with traumatic injuries in the lower extremity. Wounds were treated with a bioelectric device held in place with standard bandaging twice a week. At each follow-up visit, wounds were photographed and assessed for signs of epithelialization. All presented wounds were reduced in size or achieved complete wound closure, with an average 1.3% wound healing per day. The results of this case series demonstrate the safety and efficacy of a bioelectric device as a management option for traumatic lower-extremity wounds in equines and hold significant promise in promoting enhanced healing rates and improved aesthetic outcomes.
To determine the effect of manuka honey on second-intention healing of contaminated, full-thickness skin wounds in horses.
Experimental.
Adult Standardbred horses (n = 8).
One wound was created on the dorsomedial aspect of the third metacarpus in both forelimbs, contaminated with feces, and bandaged for 24 hours. Bandages were removed and wounds rinsed with isotonic saline solution. Wounds on 1 limb had manuka honey applied daily (n = 8) whereas wounds on the contralateral limb received no treatment (n = 8). Bandages were replaced and changed daily for 12 days, after which treatment stopped, bandages were removed, leaving wounds open to heal. Wound area was measured 24 hours after wound creation (day 1), then weekly for 8 weeks. Overall time for healing was recorded. Wound area and rate of healing of treated and control wounds were compared statistically.
Treatment with manuka honey decreased wound retraction and treated wounds remained significantly smaller than control wounds until day 42; however, there was no difference in overall healing time between treatment and control wounds.
Treatment with manuka honey reduced wound area by reducing retraction but did not affect overall healing time of full-thickness distal limb wounds using this wound-healing model.
In den vorliegenden Untersuchungen wurde die Endoskopie als Diagnostikmethode sowohl für verschiedene Erkrankungen der Ohren, des Ösophagus, des Laryngo-Tracheo-Bronchialbereiches und des Thorax bei Hunden und Katzen als auch zur Untersuchung des Schulter-, Ellbogen- und Kniegelenkes beim Hund eingesetzt und auf ihren diagnostischen Wert hin überprüft.
Starre Endoskope wurden bei fast allen untersuchten Patienten eingesetzt. Die Benutzung flexibler Endoskope für die Ösophagoskopie bei zwei untersuchten Patienten war wegen der Größe der Tiere notwendig. Länge und Größe der Optiken wurden immer der Tiergröße angepasst.
Zur Feststellung einer definitiven Diagnose wurde die Endoskopie mit bakteriologischen und zyto- bzw. histologischen Untersuchungen von endoskopisch entnommenen Proben aus der veränderten Schleimhaut des Gewebes oder der Flüssigkeiten ergänzt. Auch zum Entfernen von Fremdkörpern aus den äußeren Gehörgängen, dem Ösophagus, der Nasenhöhle, dem hinteren Rachenraum, dem Kehlkopf, der Trachea und den Bronchien sowie zur Spülung der Gehör- und der Nasengänge wurde die Endoskopie verwendet.
In der Otoskopie konnten Fremdkörper im Gehörgang, Otitis externa und Perforation des Trommelfells endoskopisch festgestellt werden.
In der Ösophagoskopie konnten Perforationen des Ösophaguslumens, Invagination des Magens in den Ösophagus und Fremdkörper im Ösophaguslumen festgestellt werden.
Die Rhinoskopie wurde zur Feststellung verschiedene Erkrankungen der rostralen und kaudalen Nasengänge z.B. Tumoren, die sich histologisch als bösartig herausstellten, Fremdkörper, mykotische Rhinitis, chronisch-eitrige Rhinitis und Verletzungen des kaudalen Nasenbereiches verwendet.
In Untersuchung des Gaumensegels konnten Verletzungen, Missbildungen und Verlängerung des Gaumensegels festgestellt werden.
In der Laryngo-Tracheo-Bronchoskopie konnte eine Laryngo-Tracheobronchitis Trachealkollaps unterschiedlicher Grade, und eine Kehlkopflähmung diagnostiziert werden.
Im linken Bronchus eines Patienten konnte ein Fremdkörper endoskopisch festgestellt und entfernt werden. Anatomisch-physiologische Abweichungen brachyzephaler Hunderassen, wie Verlängerung des Gaumensegels, Stimmtaschenvorfall und Trachealkollaps konnte auch endoskopisch erkannt.
Die Thorakoskopie wurde zur Feststellung einer eitrigen Pneumonie, pyogranulomatöse Entzündung des Mediastinums, Tumoren und Pleuritis verwendet.
Arthroskopie des Schultergelenkes konnte eine Osteochondrosis dissecans feststellen.
Mit Hilfe der Arthroskopie des Ellbogengelenkes wurde ein fragmentierter Processus coronoideus mediales ulna, isolierter Processus anconaeus ulna, Metaplasie der Gelenkkapsel und Osteochondrosis dissecans in Zusammenhang mit einem fragmentierten Processus coronoideus mediales ulna diagnostiziert.
Bei der Arthroskopie des Kniegelenkes wurde die Ruptur der Sehne des Musculus extensor digitorum longum, vollständig oder partiell Riss das vordere Kreuzband diagnostiziert. Auch Knorpeldefekte oder Synovialitis konnten endoskopisch festgestellt werden
Die Endoskopie ist ein wertvolles diagnostisches Hilfsmittel und dient als Ergänzung bei anderen diagnostischen Methoden für die Untersuchung verschiedener Erkrankungen unterschiedlicher Organsysteme. Die Technik der Endoskopie kann durch praktische Übungen erlernt und durch Erfahrung ständig verbessert werden.
Bandaging and second intention healing in distal limbs of horses blacksquare, square, filled Auricular chondrosis in a horse blacksquare, square, filled National survey of antimicrobials in the Australian pig industry blacksquare, square, filled Analgesia for knife and ring castration in lambs blacksquare, square, filled Incidence of lymphoma in a colony of baboons blacksquare, square, filled Viruses in black tiger prawns from Weipa blacksquare, square, filled Sacral osteochondrosis in German Shepherd Dogs blacksquare, square, filled Congenital pyloric obstruction from a gastric hyperplastic polyp.
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.
Equine amnion and live yeast cell derivative were evaluated as a biological dressing and as a topical wound medicament respectively, in the treatment of granulating wounds of the distal portion of the limbs of horses. Wounds measuring 2.5 × 2.5 cm were created on the dorsomedial aspect of the metacarpal and metatarsal region of all 4 limbs of 9 horses. Each wound was assigned randomly to 1 of 3 treatment groups: group C, treated with a nonadherent bandage as a control; group A, treated with amnion beneath a nonadherent bandage; and group L, treated with live yeast cell derivative beneath a nonadherent bandage. Rates of contraction and epithelialization were not significantly different among groups. Percentage of epithelialization for group A was significantly greater throughout the study than for the other groups. Number of days to complete healing was significantly less in group A and significantly greater in group L than in group C. Incidence and severity of exuberant granulation tissue were significantly less in group A than in the other 2 groups. Group L had more frequent and severe cases of exuberant granulation tissue than the other 2 groups.
Wound contraction, the centripetal or concentric reduction in size of an open wound, is essential to second-intention healing. Wound contraction is caused by movement of fibroblasts in granulation tissue collagen and pulling forces of granulation tissue myofibroblasts on the skin edges. Contraction can result in complete and normal wound closure; however, abnormalities may cause incomplete and abnormal healing. Numerous factors affect wound contraction, including the amount of skin surrounding the wound; pressure on the wound; and medications, dressings, and surgical procedures that enhance or inhibit wound contraction. Other factors that can affect wound contraction are movement, exposed bone, infection, radiation therapy, and wound shape.
Four methods of treating granulating wounds on the dorsal aspect of the metacar-pophalangeal and metatarsophalangeal joints of ponies were evaluated. The following treatments were used: Group 1—excision of the granulation tissue with no further treatment; Group 2—cryosurgery; Group 3—excision of the granulation tissue and pressure bandage; and Group 4—excision of the granulation tissue and immobilization of the limb with a plaster cast. The wounds in Group 1 healed fastest, without producing exuberant granulation tissue and with only moderate scar fibrosis. The wounds in Group 2 healed without producing exuberant granulation tissue but with marked scarring. Wounds in Groups 3 and 4 took longer (p < 0.001) to heal compared to wounds in Groups 1 and 2. Wounds in Groups 3 and 4 produced exuberant granulation tissue, but the resultant scars were the least fibrotic.
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.
Equine amnion and live yeast cell derivative were evaluated as a biological dressing and as a topical wound medicament respectively, in the treatment of granulating wounds of the distal portion of the limbs of horses. Wounds measuring 2.5 x 2.5 cm were created on the dorsomedial aspect of the metacarpal and metatarsal region of all 4 limbs of 9 horses. Each wound was assigned randomly to 1 of 3 treatment groups: group C, treated with a nonadherent bandage as a control; group A, treated with amnion beneath a nonadherent bandage; and group L, treated with live yeast cell derivative beneath a nonadherent bandage. Rates of contraction and epithelialization were not significantly different among groups. Percentage of epithelialization for group A was significantly greater throughout the study than for the other groups. Number of days to complete healing was significantly less in group A and significantly greater in group L than in group C. Incidence and severity of exuberant granulation tissue were significantly less in group A than in the other 2 groups. Group L had more frequent and severe cases of exuberant granulation tissue than the other 2 groups.
Second-intention healing (contraction and epithelization) is most appropriate for heavily traumatized, contaminated wounds that may have a prolonged debridement phase. Therapy during healing can promote rapid debridement and faster healing. Healing of lower limb wounds by second intention may be protracted, owing to poorer wound contraction and excessive granulation tissue production as compared with body wounds.
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)
Tissue hypoxia is a well-known stimulus to angiogenesis. The central dead space in healing wounds has been shown to be hypoxic (PO2 = 1 to 10). Angiogenesis is a necessary component of all healing wounds. Rabbit ear chambers were used to explore the contribution of O2 gradients and various inspired oxygen concentrations on wound healing and angiogenesis. These experiments demonstrate that: (1) A hypoxic tissue gradient is mandatory for wound-healing angiogenesis, (2) when the hypoxic gradient is destroyed capillary growth cases, and (3) inspired oxygen concentrations affect the rate and density of capillary growth.
Two 2.5-cm ² full-thickness skin wounds were created surgically over the lateral aspect of the cannon bone of each limb of 6 horses (n = 48 wounds). Dressings evaluated were a nonadherent gauze pad (group 1); a synthetic semiocclusive dressing, (group 2); equine amnion (group 3); and a synthetic fully occlusive dressing (group 4). Wounds were assessed subjectively at each dressing change, and total wound area, area of granulation tissue, and area of epithelium in each wound were determined by computerized digital analysis of photographs of the wounds. Complete healing time (wound covered by epithelium) also was determined for each wound. Statistical comparisons were made, using Kruskal-Wallis analysis and a Mann-Whitney U test.
Median time to complete healing was: group 1, 53 days; group 2, 71 days; group 3, 63 days; and group 4, 113 days. Time to complete healing was significantly longer for wounds of group-4 horses than all other groups, and wounds of group-1 horses healed faster than did those of group-2 horses ( P < 0.05). Wounds in group-4 horses required significantly ( P ≤ 0.05) more excisions of granulation tissue (median, 11.5 times) than did those in group-1 (median, 3 5), group-2 (median, 5.5) or group-3 (median, 2.5) horses. Epithelial tissue was detected later in wounds of group-4 horses (median, 27 days) than in wounds of horses in groups 1, 2 or 3 (median, 17 days); however, this difference was not statistically significant. Significant differences were not found for percentage of healing attributable to wound contraction or epithelialization. Use of synthetic semiocclusive and fully occlusive dressings resulted in significantly ( P < 0.05) prolonged healing and production of excess wound exudate, compared with control wounds. In this model, occlusion of wounds was not beneficial for healing of full-thickness skin wounds of the distal portion of the limbs of horses.
To evaluate the effect of a porous bovine-derived collagen membrane (PBCM) on the rates of wound healing, cellular events, presence of granulation tissue, and appearance at termination of the study in surgically created full-thickness cutaneous wounds of the distal portion of the extremities of horses.
Treated wounds (n = 12) received a PBCM dressing and control wounds were covered with a nonadherent dressing. Forelimbs and hind limbs were cross paired; the right forelimb and left hind limb always received the same dressing application, as did the left forelimb and right hind limb. Limbs pairs were then randomly assigned to 1 of the 2 dressings.
Six healthy male horses (3 sexually intact, 3 geldings) ranging from 2 to 10 (mean, 6.5) years and weighing between 278 and 568 (mean, 408.5) kg were studied.
Full-thickness skin wounds (6.25 cm2) were created on the dorsal metatarsi and metacarpi of the experimental animals. A preformed PBCM dressing was evaluated in half the wounds (n = 12). Control wounds (n = 12) were dressed with a nonadherent gauze dressing. At each bandage change, wounds were subjectively assessed and were photographed, and measurements of horizontal and vertical wound dimensions were documented. Wound biopsy specimens obtained on days 2, 5, 7, 10, 21, and 31 were evaluated for presence of collagen, fibrin, inflammation, epithelium, and cellular elements of healing. Planar morphometry was used to determine total wound area and granulation area from the wound photographs. Percentage of contraction and epithelialization were calculated from these values. Linear regression analysis of the square root of the total wound area and the granulation area was performed. Wound area measurements were analyzed, using ANOVA for repeated measures. Regressions were compared, using covariance analysis and ANOVA. Significance was considered at P < 0.05.
Fibrin score, neutrophil score, and degree of inflammation were significantly greater in the PBCM-treated wounds. No significant differences in the total wound, epithelialized, or contraction areas were detected between the PBCM-treated and control (nonadherent-treated) wounds. Rates of wound healing were not statistically different between the 2 treatment groups, though they were significantly slower in the hind limbs, compared with the forelimbs. Scabs were formed more frequently in the PBCM-treated wounds.
Application of a porous collagen bandage was not detrimental to full-thickness cutaneous wound healing in horses.
To determine whether transforming growth factor (TGF)-beta1 and -beta3 expression differs between equine limb wounds healing normally and those healing with experimentally induced exuberant granulation tissue (EGT).
Six wounds were created on the lateral aspect of both metacarpi of each horse; one forelimb was untreated, and the other was bandaged to stimulate the development of EGT. Sequential wound biopsies allowed comparison of growth factor expression between the two types of wound.
Four horses (2 to 4 years of age; 350 to 420 kg).
Wounds were assessed grossly, histologically, and by enzyme-linked immunosorbent assay (ELISA) for TGF-beta1 and -beta3 expression at 12 and 24 hours and 2, 5, 10, and 14 days postoperatively.
Bandaged wounds developed EGT. In all wounds, TGF-beta1 peaked early and remained elevated at 14 days. Peak TGF-beta1 concentration was higher in wounds with EGT, but not significantly so. Expression of TGF-beta3 differed from TGF-beta1, with peak TGF-beta3 concentrations being delayed. Concentrations of TGF-beta3 were higher in wounds healing normally, but this difference was not significant.
During both normal and exuberant wound repair, the expression of TGF-beta1 occurred earlier than TGF-beta3 expression. Wounds healing with EGT tended to have higher concentrations of fibrogenic TGF-beta1 and lower concentrations of antifibrotic TGF-beta3 than wounds healing normally, although these differences were not statistically significant.
This study suggests that the production of EGT in bandaged wounds may be related to increased expression of fibrogenic TGF-beta1 and decreased expression of antifibrotic TGF-beta3. Further investigation of the roles of TGF-beta1 and -beta3 may be important in understanding the molecular control of EGT in horses.
To evaluate the effect of intramuscular administration of recombinant equine growth hormone on healing of full thickness skin wounds on equine limbs.
Experimental.
Nine Standardbred horses.
In study 1, standardized full thickness skin wounds (2.5 x 2.5 cm) were made over the dorsomedial aspect of the mid-cannon bone of 1 forelimb and 1 hindlimb in 9 horses. Wounds were bandaged without treatment (control subjects) and videorecorded twice weekly until healed. Then, in study 2, similar wounds were created on the opposite limbs; 6 horses were administered intramuscular recombinant equine growth hormone (10 microg/kg daily for 7 days, then 20 microg/kg daily for 49 days), and 3 horses (control subjects) were administered equivalent volumes of sterile water. Wounds were videorecorded 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 factorial analysis of variance; significance was set at P <.05.
No differences in the measured variables were detected between wounds in study 1 and the control wounds in study 2. In recombinant equine growth hormone-treated horses, wounds retracted more during treatment and contracted faster after treatment stopped when compared with wounds from untreated horses. No other treatment effects were detected.
Recombinant equine growth hormone seemingly increases wound retraction. After treatment ceases, wound contraction increases.
Intramuscular administration of recombinant equine growth hormone (10 microg/kg daily for 7 days, then 20 microg/kg daily for 49 days) does not appear to have any beneficial clinical effect on healing of equine limb wounds.
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.
Experimental.
Eight Standardbred horses.
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.
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.
Using this model of wound healing, Solugel had no effect on second intention healing of distal limb wounds in horses.
Solugel does not appear to have any beneficial effect on healing of small full-thickness skin wounds to the distal limb of horses.
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).
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.
Eight horses, randomly assigned to one of two study groups.
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.
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.
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.
This information may help determine the appropriate time for using receptor antagonists to prevent scarring of limb wounds of horses.
The use and aims of various wound dressings are discussed. Application and indications in the horse vary according to the type and location of the wound as well as the nature and availability of the dressing material. Coaptation and immobilization are essential to promote healing in certain locations. Techniques used for bandage application in horses are described, with special emphasis on problem areas.
Second-intention repair is faster in ponies than in horses and faster in body wounds than in limb wounds. To a large extent, the differences between horses and ponies can be explained by differences in the local inflammatory response, which are a result of the functional capacity of leukocytes. In ponies, leukocytes produce more inflammatory mediators,resulting in better local defense, faster cellular debridement, and a faster transition to the repair phases, with more wound contraction. In horses,leukocytes produce fewer mediators, initiating a weak inflammatory response, which becomes chronic. This inhibits wound contraction and gives rise to the formation of exuberant granulation tissue. The anatomic environment that influences the inflammatory response and wound contraction most probably determines the differences between body and limb wounds. In body wounds, better perfusion results in faster initiation of the inflammatory phase. The weaker local resistance results in a greater degree of contraction. In limb wounds, particularly of horses, the initial inflammatory response is weak and wound contraction is restricted. Both factors give rise to chronic inflammation, which further inhibits wound contraction and promotes exuberant granulation tissue. The high incidence of exuberant granulation tissue in limb wounds of horses can thus be explained by the chronicity of the inflammatory response as well as by the common use of bandages during treatment. Chronic inflammation is often not recognized as a cause of exuberant granulation tissue. It must be prevented and treated to promote the healing process. Bandages and casts stimulate the formation of exuberant granulation tissue; however, they are advantageous in many respects and play an important role in support of the overall healing process.
The equine practitioner who is presented with a wounded horse should fully understand the physiologic mechanisms involved in repair so as to design an appropriate treatment plan. In the following articles of this issue,experienced authors share their thoughts on the management of specific injuries, and the reader should benefit from acquisition of knowledge about the different phases of healing as well as the cytokines that regulate them,because these data dictate the approach to follow, particularly in com-plicated wounds, such as those afflicted by chronic inflammation and/or an excessive proliferative response.
To determine the effect of a silicone dressing on the rate and quality of repair of limb wounds and compare microvascular occlusion and apoptosis in wounds treated with the silicone dressing and those treated with a conventional dressing in horses.
5 horses.
Horses received two 6.25-cm2 wounds on each metacarpus. Ten wounds were treated with a silicone dressing; the other 10 were treated with a control dressing. Quality of repair and wound size were evaluated at each bandage change. Time to healing and the number of excisions of exuberant granulation tissue were recorded. Biopsy specimens taken from healed wounds were evaluated semiquantitatively via histologic examination, p53 immunohistochemical analysis, terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) to quantify apoptosis, and electron microscopic examination to measure microvessel luminal diameters.
The silicone dressing surpassed the conventional dressing in preventing formation of exuberant granulation tissue and improving tissue quality. Microvessels were occluded significantly more often in wounds dressed with the silicone gel, which also diminished the expression of mutant p53, an indirect inhibitor of apoptosis, although greater apoptosis was not confirmed quantitatively by use of TUNEL.
Because the silicone dressing inhibited the formation of exuberant granulation tissue, it may be integrated in a management strategy designed to improve the repair of limb wounds in horses.
To determine whether povidone iodine ointment or 2 forms of silver sulfadiazine applied topically to wounds of the distal aspect of the limbs in horses affect the rate of second intention healing and to evaluate the additional influence of bandaging with these antimicrobials on granulation tissue formation.
6 healthy adult horses.
Six standardized 2.5-cm2 skin wounds/horse were distributed between the dorsomedial surfaces of the metacarpi and metatarsi. One of the following 6 treatments was applied to each wound: 1% silver sulfadiazine cream with bandage, 1% silver sulfadiazine slow-release matrix with bandage, 1% silver sulfadiazine slow-release matrix without bandage, povidone-iodine ointment with bandage, untreated control with bandage, and untreated control without bandage. Wound area, granulation tissue area, and perimeter were measured by use of planimetry software applied to digital images. Exuberant granulation tissue was excised when present. Days until healing, rate of healing parameter, rate of contraction, and epithelialization were compared among wound treatment groups.
Healing parameters and mean days to healing did not differ significantly among any of the wound treatment groups. Percentage wound contraction and rate of epithelialization were similar among wound treatments. All bandaged wounds produced exuberant granulation tissue, which was surgically excised; none of the unbandaged wounds produced exuberant granulation tissue.
When exuberant granulation tissue is removed, rates of epithelialization and wound contraction were not different among wound treatment groups, whether bandaged or unbandaged. Topical application of 1% silver sulfadiazine slow-release matrix on unbandaged wounds induced the same result as medications applied beneath bandages, but without exuberant granulation tissue formation.
Preliminary observations on expression of transforming growth factor 1, 3 and basic fibroblast growth factor in equine limb wounds healing normally or with proud flesh
- Theoret Cl
- Barber
- Sm
- Moyana
- Tn
- Gordon
- Jg
Theoret CL, Barber SM, Moyana TN, Gordon JG. Preliminary observations on expression of transforming growth factor 1, 3 and basic fibroblast growth factor in equine limb wounds healing normally or with proud flesh. Vet Surg 2003;31:266–277.
Experiences with the application of VET BIO SIS T in equids
- W Brenm
- B Wampfler
- Imhoff
Brenm W, Wampfler B, Imhoff A et al. Experiences with the application of VET BIO SIS T in equids. In: Vessoni A, Houlton J, Schramme, M, editors. Proceedings of the 10th Annual European Society of Veterinary Orthopaedics and Traumatology Congress, Munich, 2000;130.
Principles of wound healing
- Ts Stashak
Stashak TS. Principles of wound healing. In: Stashak TS, editor. Equine wound management. Lea and Febiger, Philadelphia, 1991;1–18.
Comparative aspects of the healing of excisional wounds on the leg and body of horses
- Jacobs Ka Dh Leach
- Fretz
Jacobs KA, Leach DH, Fretz PB et al. Comparative aspects of the healing of excisional wounds on the leg and body of horses. Vet Surg 1984;13:83–90.
Second intention wound healing in the horse: the effect of bandages and topical steroids
- Barber SM
Barber SM. Second intention wound healing in the horse: the effect of bandages and topical steroids. Proc Am Assoc Equine Pract 1989;35:107–117.
Preliminary observations on expression of transforming growth factor 1, 3 and basic fibroblast growth factor in equine limb wounds healing normally or with proud flesh
- Theoret
Experiences with the application of VET BIO SIS T in equids
- Brenmw Wampflerb Imhoffa