Preclinical evaluation of a novel silver gelling fiber dressing on Pseudomonas aeruginosa in a porcine wound infection model

The wound environment is a fertile ground for biofilm forming pathogens. Once biofilms form within the wound, they can be very challenging to eradicate. The purpose of this study was to examine the effect of a gelling fiber dressing with silver using a well‐established porcine wound biofilm model. Deep partial thickness wounds were inoculated with Pseudomonas aeruginosa ATCC 27312 and covered with a polyurethane film dressing to promote biofilm formation. Wounds were then divided into treatment groups: gelling fiber dressing with silver, gelling fiber dressing without silver, hydrofiber dressing with silver, benzethonium chloride and ethylenediaminetetraacetic acid and compared to untreated control. Microbiological, biofilm, and histological wound assessments were performed on days 3, 5, and 7 postinfection. Treatment with gelling fiber dressing with silver resulted in significant reduction of P. aeruginosa biofilm when compared to all other treatment groups on every assessment time point. In addition, gelling fiber dressing with silver treatment resulted in detachment of biofilm from the wound, while wounds treated with gelling fiber dressing with and without silver showed more granulation tissue formation on day 3. Our data show that a new gelling fiber dressing with silver was effective in reducing biofilm associated P. aeruginosa in vivo. This study may have important clinical implications especially for wounds heavily colonized with gram‐negative biofilm‐forming bacteria.     

A prospective randomised open label study to evaluate the potential of a new silver alginate/carboxymethylcellulose antimicrobial wound dressing to promote wound healing

The aim of this study was to observe both the clinical signs and symptoms of wounds at risk of infection, that is critically colonised (biofilm infected) and antimicrobial‐performance of an ionic silver alginate/carboxymethylcellulose (SACMC) dressing, in comparison with a non silver calcium alginate fibre (AF) dressing, on chronic venous leg and pressure ulcers. Thirty‐six patients with venous or pressure ulcers, considered clinically to be critically colonised (biofilm infected), were randomly chosen to receive either an SACMC dressing or a non silver calcium AF dressing. The efficacy of each wound dressing was evaluated over a 4‐week period. The primary study endpoints were prevention of infection and progression to wound healing. The SACMC group showed a statistically significant (P = 0·017) improvement to healing as indicated by a reduction in the surface area of the wound, over the 4‐week study period, compared with AF controls. In conclusion, the SACMC dressing showed a greater ability to prevent wounds progressing to infection when compared with the AF control dressing. In addition, the results of this study also showed an improvement in wound healing for SACMC when compared with a non silver dressing.     

Development of a PHMB hydrogel‐modified wound scaffold dressing with antibacterial activity

Current wound scaffold dressing constructs can facilitate wound healing but do not exhibit antibacterial activity, resulting in high infection rates. We aimed to endow wound scaffold dressing with anti‐infective ability by polyhexamethylenebiguanide (PHMB). We prepared PHMB hydrogel at varying concentrations (0.25%, 0.5%, 1%, 2%) and assessed release and cytotoxicity. PHMB hydrogel was added to the wound scaffold dressing to generate a PHMB hydrogel‐modified wound scaffold dressing. Wound healing and infection prevention were evaluated using a full‐thickness skin defect model in rats. In vitro, the hydrogel PHMB release time positively correlated with PHMB concentration, with 1% allowing sufficiently long release time to encompass the high‐incidence period (3‐5 days) of infection following wound scaffold dressing implantation. Implantation of 1% PHMB hydrogel into the skin did not cause adverse responses. in vitro cytotoxicity assays showed the PHMB hydrogel‐modified wound scaffold dressing did not significantly affect proliferation of fibroblasts or vascular endothelial cells, 99.90% vs 99.84% for fibroblasts and 100.21% vs 99.28% for vascular endothelial cells at 21 days. Transplantation of PHMB hydrogel‐modified wound scaffold dressing/unmodified wound scaffold dressing on the non‐infected wounds of rats yielded no significant difference in relative vascularization rate, 47.40 vs 50.87 per view at 21 days, whereas bacterial content of the wound tissue in the PHMB hydrogel‐modified wound scaffold dressing group was significantly lower than the unmodified wound scaffold dressing group, (1.80 ± 0.35) × 10³ vs (9.34 ± 0.45) × 10³ at 14 days. Prevalence of persistent wound infection in the rats receiving PHMB hydrogel‐modified wound scaffold dressing transplantation onto infected wounds was significantly lower than the unmodified wound scaffold dressing group, 30% vs 100%. PHMB hydrogel‐modified wound scaffold dressing exhibited suitable antibacterial ability, and its biological activity did not significantly differ from that of the unmodified wound scaffold dressing, thereby allowing it to effectively prevent infection following wound scaffold dressing implantation.     

Randomised clinical trial of Hydrofiber dressing with silver versus povidone-iodine gauze in the management of open surgical and traumatic wounds

This prospective, randomised clinical trial compared pain, comfort, exudate management, wound healing and safety with Hydrofiber dressing with ionic silver (Hydrofiber Ag dressing) and with povidone-iodine gauze for the treatment of open surgical and traumatic wounds. Patients were treated with Hydrofiber Ag dressing or povidone-iodine gauze for up to 2 weeks. Pain severity was measured with a 10-cm visual analogue scale (VAS). Other parameters were assessed clinically with various scales. Pain VAS scores decreased during dressing removal in both groups, and decreased while the dressing was in place in the Hydrofiber Ag dressing group (n = 35) but not in the povidone-iodine gauze group (n = 32). Pain VAS scores were similar between treatment groups. At final evaluation, Hydrofiber Ag dressing was significantly better than povidone-iodine gauze for overall ability to manage pain (P < 0.001), overall comfort (P < or = 0.001), wound trauma on dressing removal (P = 0.001), exudate handling (P < 0.001) and ease of use (P < or = 0.001). Rates of complete healing at study completion were 23% for Hydrofiber Ag dressing and 9% for povidone-iodine gauze (P = ns). No adverse events were reported with Hydrofiber Ag dressing; one subject discontinued povidone-iodine gauze due to adverse skin reaction. Hydrofiber Ag dressing supported wound healing and reduced overall pain compared with povidone-iodine gauze in the treatment of open surgical wounds requiring an antimicrobial dressing.     

Wound‐healing effect of adipose stem cell‐derived extracellular matrix sheet on full‐thickness skin defect rat model: Histological and immunohistochemical study

The potential use of extracellular matrix (ECM) as a source of wound dressing material has recently received much attention. The ECM is an intricate network of various combinations of elastin, collagens, laminin, fibronectin, and proteoglycans that play a key role in stimulating cell proliferation and differentiation. We evaluated the efficacy of an ECM sheet derived from human adipose tissue as a wound dressing material to enhance healing. We prepared a novel porous ECM sheet dressing scaffold from human adipose tissue. in vitro analysis of the ECM sheets showed efficient decellularisation; absence of immunostimulatory components; and the presence of a wide number of angiogenic and bioactive factors, including collagen, elastin, and proteoglycans. To evaluate in vivo efficacy, full‐thickness excisional wounds were created on the dorsal skin of a rat, and the ECM sheets; secondary healing foam wound dressing, Healoderm; or a conventional dressing were applied to each wound site. Photographs were taken every other day, and the degree of reepithelialisation of the wounds was determined. Application of an ECM sheet dressing enhanced the macroscopic wound‐healing rate on days 4, 7, and 10 compared with that in the control group. Microscopic analysis indicated that the reepithelialisation rate of the wound was higher in the ECM group compared with that in the control group; the reepithelialisation rate was better than that of the secondary healing foam wound dressing. Moreover, a denser and more organised granulation tissue was formed in the ECM sheet group compared with that in the secondary healing foam wound dressing and control groups. The ECM sheet also showed the highest microvessel density compared with the secondary healing foam wound dressing and control groups. Based on these data, we suggest that a bioactive ECM sheet dressing derived from human adipose can provide therapeutic proteins for wound healing.     

Anti-biofilm efficacy of a lactoferrin/xylitol wound hydrogel used in combination with silver wound dressings

With an epidemic increase in obesity combined with an ageing population, chronic wounds such as diabetic foot ulcers, pressure ulcers and venous leg ulcers are an increasing clinical concern. Recent studies have shown that bacterial biofilms are a major contributor to wound bioburden and interfere with the normal wound healing process; therefore, rational design of wound therapies should include analysis of anti‐biofilm characteristics. Studies using the combined treatment of bacterial biofilms with the innate immune molecule lactoferrin and the rare sugar‐alcohol xylitol have demonstrated an antimicrobial capacity against a clinical wound isolate. Studies presented here used a colony‐drip‐flow reactor biofilm model to assess the anti‐biofilm efficacy of a lactoferrin/xylitol hydrogel used in combination with commercially available silver‐based wound dressings. Log reductions in biofilm viability are compared with a commercially available wound hydrogel used in combination with the silver‐based wound dressings. For both a single species biofilm and a dual species biofilm, the lactoferrin/xylitol hydrogel in combination with the silver wound dressing Acticoat? had a statistically significant reduction in biofilm viability relative to the commercially available wound hydrogel. This study also demonstrated a statistical interaction between the lactoferrin/xylitol hydrogel and the silver wound dressing.     

Enhanced wound‐healing performance of a phyto‐polysaccharide‐enriched dressing – a preclinical small and large animal study

Alginate is a natural rich anionic polysaccharide (APS), commonly available as calcium alginate (CAPS). It can maintain a physiologically moist microenvironment, which minimises bacterial infection and facilitates wound healing at a wound site. Patients with burn injuries suffer from pain and an inflammatory response. In this study, we evaluated the CAPS dressing and traditional dressing containing carboxymethyl cellulose (CMC) for wound healing and scar tissue formation in a burn model of rat and swine. In our pilot study of a burn rat model to evaluate inflammatory response and wound healing, we found that the monocyte chemoattractant protein (MCP)‐1 and transforming growth factor (TGF)‐β were up‐regulated in the CAPS treatment group. Next, the burn swine models tested positive for MCP‐1 in a Gram‐positive bacterial infection, and there was overproduction of TGF‐β during the burn wound healing process. Rats were monitored daily for 1 week for cytokine assay and sacrificed on day 28 post‐burn injury. The swine were monitored over 6 weeks. We further examined the pain and related factors and inflammatory cytokine expression in a rodent burns model monitored everyday for 7 days post‐burn. Our results revealed that the efficacy of the dressing containing CAPS for wound repair post‐burn was better than the CMC dressing with respect to natural wound healing and scar formation. The polysaccharide‐enriched dressing exerted an antimicrobial effect on burn wounds, regulated the inflammatory response and stimulated anti‐inflammatory cytokine release. However, one pain assessment method showed no significant difference in the reduction in levels of adenosine triphosphate in serum of rats after wound dressing in either the CAPS or CMC group. In conclusion, a polysaccharide‐enriched dressing outperformed a traditional dressing in reducing wound size, minimising hypertrophic scar formation, regulating cytokines and maximising antimicrobial effects.     

A PEGylated fibrin hydrogel‐based antimicrobial wound dressing controls infection without impeding wound healing

Combat injuries are associated with a high incidence of infection, and there is a continuing need for improved approaches to control infection and promote wound healing. Due to the possible local and systemic adverse effects of standard 1% cream formulation (Silvadene), we had previously developed a polyethylene glycol (PEGylated) fibrin hydrogel (FPEG)‐based wound dressing for the controlled delivery of silver sulfadiazine (SSD) entrapped in chitosan microspheres (CSM). In this study, we have evaluated the antimicrobial and wound healing efficacy of SSD‐CSM‐FPEG using a full‐thickness porcine wound infected with Pseudomonas aeruginosa. Infected wounds treated with a one‐time application of the SSD‐CSM‐FPEG wound dressing demonstrated significantly reduced bacterial bioburden over time (99·99% of reduction by day 11; P < 0·05) compared with all the other treatment groups. The epithelial thickness and granulation of the wound bed was significantly better on day 7 (150·9 ± 13·12 µm), when compared with other treatment groups. Overall, our findings demonstrate that the SSD‐CSM‐FPEG wound dressing effectively controls P. aeruginosa infection and promotes wound healing by providing a favourable environment that induces neovascularisation. Collectively, sustained release of SSD using fibrin hydrogel exhibited enhanced benefits when compared with the currently available SSD treatment, and this may have significant implications in the bacterial reduction of infected wounds in military and civilian populations.     

Efficacy of a surfactant‐based wound dressing on biofilm control

The aim of this study was to evaluate the efficacy of both a nonantimicrobial and antimicrobial (1% silver sulfadiazine—SSD) surfactant‐based wound dressing in the control of Pseudomonas aeruginosa, Enterococcus sp, Staphylococcus epidermidis, Staphylococcus aureus, and methicillin‐resistant S. aureus (MRSA) biofilms. Anti‐biofilm efficacy was evaluated in numerous adapted American Standards for Testing and Materials (ASTM) standard biofilm models and other bespoke biofilm models. The ASTM standard models employed included the Minimum biofilm eradication concentration (MBEC) biofilm model (ASTM E2799) and the Centers for Disease Control (CDC) biofilm reactor model (ASTM 2871). Such bespoke biofilm models included the filter biofilm model and the chamberslide biofilm model. Results showed complete kill of microorganisms within a biofilm using the antimicrobial surfactant‐based wound dressing. Interestingly, the nonantimicrobial surfactant‐based dressing could disrupt existing biofilms by causing biofilm detachment. Prior to biofilm detachment, we demonstrated, using confocal laser scanning microscopy (CLSM), the dispersive effect of the nonantimicrobial surfactant‐based wound dressing on the biofilm within 10 minutes of treatment. Furthermore, the non‐antimicrobial surfactant‐based wound dressing caused an increase in microbial flocculation/aggregation, important for microbial concentration. In conclusion, this nonantimicrobial surfactant‐based wound dressing leads to the effective detachment and dispersion of in vitro biofilms. The use of surfactant‐based wound dressings in a clinical setting may help to disrupt existing biofilm from wound tissue and may increase the action of antimicrobial treatment.     

Expectation‐induced placebo responses fail to accelerate wound healing in healthy volunteers: results from a prospective controlled experimental trial

Placebo responses have been shown to affect the symptomatology of skin diseases. However, expectation‐induced placebo effects on wound healing processes have not been investigated yet. We analysed whether subjects' expectation of receiving an active drug accelerates the healing process of experimentally induced wounds. In 22 healthy men (experimental group, n = 11; control group, n = 11) wounds were induced by ablative laser on both thighs. Using a deceptive paradigm, participants in the experimental group were informed that an innovative ‘wound gel’ was applied on one of the two wounds, whereas a ‘non‐active gel’ was applied on the wound of the other thigh. In fact, both gels were identical hydrogels without any active components. A control group was informed to receive a non‐active gel on both wounds. Progress in wound healing was documented via planimetry on days 1, 4 and 7 after wound induction. From day 9 onwards wound inspections were performed daily accompanied by a change of the dressing and a new application of the gel. No significant differences could be observed with regard to duration or process of wound healing, either by intraindividual or by interindividual comparisons. These data document no expectation‐induced placebo effect on the healing process of experimentally induced wounds in healthy volunteers.     

Enhanced healing of mitomycin C‐treated healing‐impaired wounds in rats with hydrosheets composed of chitin/chitosan,fucoidan, and alginate as wound dressings

To create a moist environment for rapid wound healing, a hydrosheet composed of alginate, chitin/chitosan, and fucoidan (ACF‐HS) has been developed as a functional wound dressing. The aim of this study was to evaluate the accelerating effect of ACF‐HS on wound healing for rat mitomycin C‐treated healing‐impaired wounds. Full‐thickness skin defects were made on the back of rats and mitomycin C was applied onto the wound for 10 minutes to prepare a healing‐impaired wound. After thoroughly washing out the mitomycin C, ACF‐HS was applied to the healing‐impaired wounds. The rats were later euthanized and histological sections of the wounds were prepared. The histological examinations showed significantly advanced granulation tissue and capillary formations in the healing‐impaired wounds treated with ACF‐HS on days 7 and 14, in comparison with that in alginate fiber (Kaltostat^®), hydrogel wound dressing (DuoACTIVE^®), and nontreatment (negative control). Furthermore, in cell culture studies, ACF‐HS‐absorbed serum and fibroblast growth factor‐2 was found to be proliferative for fibroblasts and endothelial cells, respectively, and ACF‐HS‐absorbed serum was found to be chemoattractive for fibroblasts. However, our results may not be strictly comparable with general healing‐impaired wound models in humans because of the cell damage by mitomycin C. In addition, more biocompatibility studies of fucoidan are essential due to the possibility of renal toxicity.     

Epidermal growth factor‐containing wound closure enhances wound healing in non‐diabetic and diabetic rats

Background: This study was designed to elucidate the in vivo efficacy of epidermal growth factor (EGF) on wound healing in non diabetic and diabetic rats. Methods: Ninety‐six male Wistar‐Albino rats were randomly divided into six groups. Saline‐moistened gauze, pure gelatin or EGF in gelatin‐microsphere dressings were used in a dermal excision model in both normal and streptomycin‐induced diabetic rats. Wound healing was evaluated on day 7 and 14. Reduction in wound area, hydroxypyroline content and tensile strength of the wound were evaluated in each rat. Tissue samples taken from the wounds were examined histopathologically for reepithelialisation, cellular infiltration, number of fibroblasts, granulation and neovascularisation. Results: On day 7, the use of EGF‐containing dressing was observed to reduce the wound area better when compared with the other dressings tested. This effect was significant in normal rats rather than diabetic rats. The difference in reduction of wound area did not persist on day 14. No significant effect on hydroxyproline content of the wound was found with EGF‐containing dressing in either normal or diabetic rats. There was a statistically significant increase in tensile strength values of EGF‐applied non diabetic rats over the 14 day period. An increase in tensile strength was prominent in also EGF‐applied diabetic rats on day 14. Histological examination revealed higher histopathologic scores in EGF‐applied diabetic and non diabetic rats. Conclusion: These findings implicate that use of EGF in gelatin‐microsphere dressings improves wound healing both in normal and diabetic rats.     

Evaluation of autologous bone marrow‐derived nucleated cells for healing of full‐thickness skin wounds in rabbits

The aim of the study was to evaluate the potential of autologous bone marrow‐derived nucleated cells to enhance the rate of healing of full‐thickness excisional skin wounds in rabbits. The study was conducted on 20 New Zealand white rabbits of either sex. Two, 2 × 2 cm full‐thickness skin (thoracolumabar region) excisional wounds were created; one on each side of the dorsal midline in each animal. The wounds were randomly assigned to either injection of autologous bone marrow‐derived nucleated cells into the wound margins (BI), or topical application of sterile saline solution (normal saline, NS), which served as control. The wound healing was assessed by evaluation of granulation tissue formation, wound contraction, epithelisation and histopathological and histochemical changes up to 28 days after creation of the wound. Granulation tissue appeared significantly faster in BI‐treated wounds (3.22 ± 0.22 days) than in NS‐treated wounds (4.56 ± 0.47 days). Better epithelisation was seen histologically in BI wounds than in NS‐treated wounds. Wound contraction was significantly more in BI wounds when compared with NS wounds on 21 post‐surgery. Histopathological examination of the healing tissue showed early disappearance of inflammatory reaction, significantly more neovascularisation, and more fibroplasias and early lay down and histological maturation of collagen in BI wounds than in control wounds. It was concluded that injection of autologous bone marrow‐derived nucleated cells in the wound margins induced faster and better quality healing of excisional skin wounds in rabbits when compared with normal saline. The injection of autologous bone marrow‐derived nucleated cells can be used to promote healing of large full‐thickness skin wounds in rabbits.     

Increasing the presence of biofilm and healing delay in a porcine model of MRSA‐infected wounds

Data supporting the concept that microbial biofilms are a major cause of non‐healing ulcers remain limited. A porcine model was established where delayed healing resulted from methicillin‐resistant Staphylococcus aureus (MRSA) infection in full‐thickness wounds. At the end of one study a wound remaining open was sampled and a MRSA strain was isolated. This pig‐passaged strain was used as the inoculating strain in several subsequent studies. The resulting MRSA wound infections exhibited a greater, more stable tissue bioburden than seen in studies using the parent strain. Furthermore, wounds infected with the passaged strain experienced a greater delay in healing. To understand whether these changes corresponded to an increased biofilm character of the wound infection, wound biopsy samples from studies using either the parent or passaged MRSA strains were examined microscopically. Evidence of biofilm was observed for both strains, as most samples at a minimum had multiple isolated, dense microcolonies of bacteria. However, the passaged MRSA resulted in bacterial colonies of greater frequency and size that occurred more often in concatenated fashion to generate extended sections of biofilm. These results provide a model case in which increasing biofilm character of a wound infection corresponded with a greater delay in wound healing.     

Effect of piracetam and nimodipine on full‐thickness skin burns in rabbits

The potential of several drugs for full‐thickness skin burns has been investigated, but the treatment of such burns remains a challenge in plastic surgery. The present study was designed to determine the effect of systemic and topical administration of piracetam and nimodipine on full‐thickness skin burn wound healing. A total of 36 New Zealand male rabbits were divided into six groups. Full‐thickness skin burns were produced in all the groups, except the control group. Piracetam was administered systemically (piracetam‐IV) and topically (piracetam‐C) for 14 days, and nimodipine was administered systemically (nimodipine‐IV) and topically (nimodipine‐C) over the burn wounds for 14 days. The sham group underwent burn injury but was not administered any drug. After 21 days, gross examination and histopathological analysis were performed and the results were compared statistically. Nimodipine‐C and nimodipine‐IV had no effect on burn wound healing. However, both piracetam‐IV and piracetam‐C significantly enhanced the healing of the full‐thickness skin burn wounds, although the latter was more effective, useful and practical in burn wound healing. The histopathological features of the wounds in the piracetam‐C group were closer to those of the control group than those of the other groups. Piracetam‐C rather than piracetam‐IV may promote full‐thickness burn wound healing in rabbits.     

Effectiveness of a polyhexanide irrigation solution on methicillin‐resistant Staphylococcus aureus biofilms in a porcine wound model

Irrigation and removal of necrotic debris can be beneficial for proper healing. It is becoming increasingly evident that wounds colonized with biofilm forming bacteria, such as Staphylococcus aureus (SA), can be more difficult to eradicate. Here we report our findings of the effects of an irrigation solution containing propyl‐betaine and polyhexanide (PHMB) on methicillin‐resistant Staphylococcus aureus (MRSA) biofilms in a porcine wound model. Thirty‐nine deep partial thickness wounds were created with six wounds assigned to one of six treatment groups: (i) PHMB, (ii) Ringer's solution, (iii) hypochlorous acid/sodium hypochlorite, (iv) sterile water, (v) octenidine dihydrochloride, and (vi) octenilin. Wounds were inoculated with MRSA and covered with a polyurethane dressing for 24 hours to allow biofilm formation. The dressings were then removed and the wounds were irrigated twice daily for 3 days with the appropriate solution. MRSA from four wounds were recovered from each treatment group at 3 days and 6 days hours after initial treatment. Irrigation of wounds with the PHMB solution resulted in 97·85% and 99·64% reductions of MRSA at the respective 3 days and 6 days assessment times when compared to the untreated group. Both of these reductions were statistically significant compared to all other treatment groups (P values <0·05).     

The effect of a silver-containing Hydrofiber dressing on superficial wound bed and bacterial balance of chronic wounds

The treatment of chronic wounds represents a major cost to society and has a profound effect on the participant's quality of life. Chronic wounds may have an increased bacterial burden that can impair healing without all the clinical signs of infection. Silver dressings may provide an alternative topical method to control bacterial burden. The primary aim of this study was to evaluate the clinical improvement in chronic wounds through the effect on wound size, maceration, resolution of surface slough and conversion to healthy granulation during a 4-week application of the silver-containing Hydrofiber dressing. This was a single centre, open-label case series study which included a total of 30 evaluable participants: four with diabetic neuropathic foot ulcers, 13 venous stasis ulcers, four pressure ulcers and nine miscellaneous wounds that did not fit any of the previous categories. All participants had adequate vascular supply, indicating the potential to heal. The wounds were stalled or had the signs and symptoms consistent with critical colonisation. The underlying cause of the ulceration was identified and corrected, or the symptoms and signs were treated. This was followed by the application of silver-containing Hydrofiber dressings for a period of 4 weeks. The majority of wounds treated decreased in size (70%) with decreased exudate, decreased purulence and resolution of surface slough (75%). There was an increased quality and quantity of healthy granulation tissue. Unlike some silver dressings, the Hydrofiber and silver combination dressing was unlikely to cause burning and stinging on application. Peri-wound maceration was present in 54% of participants at baseline, and 85% of these resolved with this dressing. A desloughing action was seen in those patients with pre-existing slough at baseline and its removal will lower the bacterial burden of the wound.     

Effect of Acticoat® and Cutinova Hydro® on wound healing

In this study, the effects of the wound‐covering materials, Acticoat^® and Cutinova Hydro^®, on wound healing have been studied in rabbit models with open and tissue‐lost wounds with full‐thickness flank excisions. Rabbits were used as subjects with three groups of four rabbits each, and trial periods of 7, 14 and 21{\uns}days. Four circular wounds, of 1.5 cm diameter were made two on the right (one of them control) and two on the left (one of them control) of the dorsal sides of the abdomen. Acticoat^® and Cutinova Hydro^® were applied on the wounds with suture for a period of 21 days and one each placed on the right and left sides as control with gauze. Biopsy specimens were taken from the animals at the end of the research period to check the length of the epithelium, epithelial thickness, size of wounds, wound granulation tissue formation and histopathological evaluation for clarity. The Acticoat^® group showed better healing and scar formation compared to the Cutinova Hydro^® group by macroscopic examination. Epithelial wound length and clarity in terms of statistical difference occurred on day 21 (P <0.05); while the length of the wound epithelium decreased patency, epithelial thickness on days~7, 14 and 21, showed no statistical differences (P >0.05). As a result, the Acticoat^® wound dressing was determined as a more reliable for the early wound healing. This study has shown the short‐term clinical benefits of hydroactive, polyurethane dressings in the management of acute wounds. However, longer periods of wound healing procedure should be planned for reliable and safe results of wound dressing. It has also been concluded that microbiological analyses should be included for more robust and reliable comparisons.     

Influence of various treatments including povidone‐iodine and healing stimulatory reagents in a rabbit ear wound model

Selecting an appropriate treatment for a given case of skin wound is crucial for inducing optimal healing. We used an animal model developed from normal rabbit ears in order to assess the efficacy of treatments for skin wounds with or without a wet dressing, anti microbial reagent or topical wound‐stimulatory reagents. The degree of healing in each group was evaluated and compared using four histological parameters: (i) degree of reepithelialisation, (ii) amount of granulation tissue formation, and (iii) the number of capillary lumens and (iv) fibroblasts in the granulation tissue. Treatment using wet dressings resulted in an increase in capillary number compared with the open dry wound. Although the retention of povidone‐iodine (PI) in wound tissue after application significantly inhibited reepithelialisation (P < 0·05), rinsing PI off with saline was comparable in effect to using only a wet dressing. The three topical reagents, namely, basic fibroblast growth factor, prostaglandin E1 and dibutyryl cyclic adenosine monophosphate, significantly improved reepithelialisation (P < 0·05). In conclusion, wounds should be kept hydrated by applying topical reagents. If there are any signs of bacterial infection, PI can be applied and rinsed later with saline in order to minimise its cytotoxic effects.