Experimental Burn Injury Research Articles

Development of an experimental heterogeneous burn wound model

BackgroundMany research-based burn models rely on creating homogenous burns that are subsequently studied and treated. However, the majority of burn wounds sustained – and in particular those that are combat-related – are heterogeneous in nature, with varying degrees of severity intermixed throughout the entire wound, creating a complex debridement and overall treatment plan. The purpose of this study was to develop a clinically relevant heterogeneous porcine burn wound model. Materials and methodsThis study consisted of 3 anesthetized pigs with up to 6 heterogeneous 10 cm x 10 cm burn wounds. The burns were created using a thermocouple device with a square plate (5 cm x 5 cm) heated to 100 °C applied to the skin at constant pressure. The device was applied for a duration between 2–20 s for each burn segment to create burns of varying severity (superficial, partial-thickness, and full-thickness). Each heterogeneous burn wound consisted of 4 separate 5 cm x 5 cm burns, each with different and randomized burn times. Macroscopic images of the burns were obtained on days 0, 1, and 3. A punch biopsy was collected from each burn segment (1 of each depth) to determine the burn depth on day 0. On day 3, after euthanasia, all of the burns were harvested to give a cross-sectional view of the burn. ResultsHistology demonstrated that heterogeneous burns were created and burn progression was evident during the 3-day follow-up time. The depth of the burn wound significantly correlated with the burn time. By day 3, the 20-second burn wound had the deepest depth at 1003 ± 67 µm while the 2-second burn wound had the shallowest depth of burn at 258 ± 19 µm. Burn heterogeneity was also demonstrated with laser speckle image analysis. By day 3, the superficial blood flow for 20, 15, 12, 9, and 6 s burn times was below 85 AU. The 2 s burn mean flux (138 ± 48 AU) was noticeably different from other groups and well above the intact skin values (102 ± 4 AU). It was also shown that on day 3, at least 1 burn for each burn time resulted in identifiable infection via macroscopic imaging. ConclusionsThe heterogeneity of burn wounds creates a clinical challenge. This model will help to create burns that are more similar to the heterogeneous burn wounds that are seen in clinical practice and will help further research efforts in treating burns.

Comparison of The Effectiveness of Thymoquinone, St. John Wort Oil and Silver Sulfadiazine in Experimental Burn Wounds.

We aimed to compare the effectiveness of thymoquinone (TQ), most important bioactive component of black cumin, St. John wort (SJW) oil, a traditional medicinal plant used in burns, and silver sulfadiazine (AgSD), well-known anti-inflammatory agent used in modern medicine, in an experimental burn rat-model. 63 Wistar-Albino rats were randomly divided into 9 groups (n=7). TQ, SJW were administered topically and systemically but AgSD was applied topically. Epithelialization, inflammatory cell response, granulation tissue, vascularization, and fibrosis were evaluated. Malondialdehyde (MDA), total antioxidant status (TAS), total oxidant status (TOS), vitamin E, 8-hydroxy-deoxyguanosine (8-OHdG), coenzyme Q10 (CoQ10) were analyzed in serum. Topical TQ accelerated theepithelialization, enabled granulation, vascularization and fibrosis in wounds (P=0.001). Topical and systemic TQ increased Vitamin-E levels (P=0.003) but reduced TOS and 8-OHdG levels (P=0.001). Topical SJW reduced granulation and vascularization. Topical and systemic SJW decreased TOS, MDA and 8-OHdG levels (P=0.001), but increased TAS (P=0.001), and Vitamin-E levels (P=0.003). Topical AgSD reduced TOS, 8-OHdG, MDA levels (P=0.001). Topical and systemic TQ demonstrated significant advantages in accelerating wound healing process, while also enhancing antioxidant defenses and reducing oxidative damage. SJW oil, particularly in topical application, improved epithelialization and antioxidant status but showed less efficacy in systemic use. AgSD, while effective in reducing oxidative stress, was less successful in promoting wound healing and appeared to delay granulation and fibrosis. TQ offers superior protective and healing benefits, SJW is effective locally but less so systemically, and AgSD should be used cautiously, potentially combined with antioxidants to mitigate its negative impact on wound healing.

ON THE QUESTION OF THE EFFECT OF REGENERATION STIMULATION DRUGS ON THE RESTORATION OF THE SKIN IN CASE OF INJURY

Background. The study of the reaction of tissue (epidermis and dermis) to the medication of regeneration stimulants (МSR) in injuries is relevant both for the development of wound coatings and treatment regimens for the traumatic process. In this study, special attention is paid to the process of stimulation of stem cells in the hair papilla, which play an important role in the restoration of skin structures. The aim of the study was also to study the morphological changes of the epidermis and dermis in the dynamics of trauma. Materials and methods. To conduct the experiment, experimental groups were formed: a burn model without treatment; a burn model with a МSR preparation (oral administration and wound coating); an experimental group with a linear wound with МSR treatment, an experimental group similar reproduction of a wound without suturing with МSR, a control group similar reproduction of a wound without treatment with suturing, a control group - similar reproduction of the wound without treatment and without suturing. Animals were removed from the experiment by inhalation of ether vapors in accordance with the "Rules for carrying out work using experimental animals" and in accordance with the principles of the Helsinki Declaration of the World Medical Association (Declaration of Helsinki, and approved by the Institutional Review Board). Tissue fragments were taken from the site of thermal trauma and healthy tissue for the preparation of histological preparations. The production of paraffin histological sections with a thickness of 5-7 microns was carried out according to generally accepted standard methods. The sections were stained with hematoxylin and eosin. The photos were taken using the Vision Bio system (Epi 2014) and stained with hematoxylin-eosin, which were examined under x100 magnification. The obtained data were processed using MS Excel and Statgraphics software packages using generally accepted methods of statistics. Results. When reproducing thermal trauma In the control group on day 14, there is no epidermis in part of the visual fields within the studied material, the layers are replaced by connective tissue strands, scar tissue is visualized. The dermis is moderately edematous, with neutrophilic and lymphocytic infiltration is weakly expressed, in the papillary and reticular layer it is evenly represented, there are single apoptotic corpuscles. No areas of hemorrhage were detected, but the blood vessels were dilated. While in the experimental group there are signs of restoration of microcirculation with a large number of vessels and a more pronounced layer of the epidermis. When examining scars after a linear wound, it was found that animals who did not receive therapy have a thin scar, and in animals who received МSR, the consequences of surgical intervention are not visualized. Conclusion. The dynamics of the wound process was studied when using a prototype ointment containing a regeneration complex in the treatment of burn and linear wounds in an experiment. The effectiveness of the regenerative complex of a prototype ointment for the treatment of experimental burn and linear wounds in laboratory animals in comparison with the control group was revealed. It has been established that in the treatment of burn and linear wounds with experimental ointment, the healing period of burn wounds is reduced due to more active formation of the microcirculatory bed and the early onset of epithelization.

Structural and functional assessment of the condition of wound bed using microwave dielectrometry and laser doppler flowmetry

The aim of the work was to develop and test a combined method for assessing the structural and functional features of the burn wound and periwound area with the use of microwave dielectrometry and Dopplerometry. The study was performed on twenty Wistar rats, thermal injuries from contact were created on each rat, and ten healthy animals. The assessment of the wound condition was performed 24 and 72 hours after burn injury. The study of the dielectric properties of tissues was carried out using a hardware and software complex for near-field resonant microwave sensing. From the results of our studies, it can be concluded that in the early post-injury period (within the first days), a sharp coordinated decrease in the intensity of microcirculation and dielectric permittivity is observed in the wound tissues, gradually and partially restored by the end of the third day after burning. The increased microcirculatory blood flow to the periwound area, leading to an increase in the degree of tissue hydration was observed, and as a consequence, the values of these two indices became higher. In addition, it has been shown that during thermal trauma, a regulatory imbalance of factors providing capillary blood flow around a burn wound area and surrounding tissues is formed, which is compensatory in nature and, in the absence of adequate correction, contributes to the inhibition of regeneration processes. Thus, the combination of the methods used in this study may potentially provide more specific information for a description of the structural and functional features of the analyzed tissue and their dynamics. This is clearly shown by the example of an experimental burn wound.

In vivo monitoring of hemoglobin derivatives in a rat thermal injury model using spectral diffuse reflectance imaging

IntroductionTo demonstrate the feasibility of our previously proposed Diffuse reflectance spectral imaging (DRSI) method for in vivo monitoring of oxygenated hemoglobin, deoxygenated hemoglobin, methemoglobin, tissue oxygen saturation, and methemoglobin saturation in a rat scald burn wound model and assess whether the method could be used for differentiating the burn depth groups in rats based on the hemoglobin parameters. MethodologySuperficial dermal burns (SDBs), deep dermal burns (DDBs), and deep burns (DBs) were induced in rat dorsal skin using a Walker–Mason method. An approach based on multiple regression analysis for spectral diffuse reflectance images aided by Monte Carlo simulations for light transport was used to quantify the hemoglobin parameters. Canonical discriminant analysis (CDA) was performed to discriminate SDB, DDB, and DB. ResultsCDA using the total hemoglobin concentration, tissue oxygen saturation, and methemoglobin saturation as the independent variables showed good performance for discriminating the SDB, DDB, and DB groups immediately after burn injury and the SDB group from the DDB and DB groups 24–72 h after burn injury. ConclusionsThe DRSI method with multiple regression analysis for quantification of oxygenated hemoglobin, deoxygenated hemoglobin, and methemoglobin proved to be reliable for monitoring these hemoglobin derivatives in the rat experimental burn injury model. The parameters of tissue oxygen saturation, methemoglobin saturation, and total hemoglobin concentration are promising for the differentiating the degree of burn injury using CDA.

Characteristics of endotoxemia in different ways of treatment of experimental burn in rats

The article evaluates the dynamics of toxemia and detoxification capabilities of various wound dressings in thermal burn injury in rats in the experiment. A wound dressing based on collagen and chitosan Collachit® and a membrane wound dressing containing a hyperosmolar solution in the cavity were compared. Studies of the dynamics of toxemia in burn disease after experimental thermal injury were carried out on Wistar rats (n=20). Analysis of the results of the study was carried out on the basis of clinical, morphological and biochemical parameters of the peripheral blood of rats with experimental burn injury. The study of the morphology of blood cells is carried out according to generally accepted methods. Biochemical manifestations of endotoxemia are established by the dynamics of ALT, AST, urea, creatinine. In the 1st group of rats (n=10), the Collachit® wound dressing was applied. In the 2nd group (n=10), a semi -permeable membrane filled with a hyperosmolar solution, constituting a necrolytic enzyme, was fixed on the surface of the burn. As a result, it was found that burn toxemia in rats proceeded in 2 phases and was accompanied by depression, food refusal, leukocytosis, increased LII, liver transferases, creatinine and urea. Hematological deviations were characterized by non-uniform dynamics, corresponding to the phase of burn toxemia with maximum increases on days 1-2 and 5-7, a fall on days 3-4, and days 8-10. Hematological manifestations of toxemia depended on the method of treatment and were less pronounced with the use of membrane wound dressings than with collachitis. External signs of toxemia do not in all cases correspond to the hematological and biochemical profile of toxemia, which indicates the possibility of a latent course of burn disease with some methods of treatment. The applied wound dressings had a pronounced antiseptic efficacy, characterized by the absence of purulent-inflammatory complications over the entire period of the experiment.

ОЦЕНКА ЭФФЕКТИВНОСТИ ЛЕЧЕНИЯ ЭКСПЕРИМЕНТАЛЬНЫХ ОЖОГОВЫХ РАН ПО РЕЗУЛЬТАТАМ ЛАБОРАТОРНЫХ И МОРФОЛОГИЧЕСКИХ ИССЛЕДОВАНИЙ

Purpose of the study: to study the dynamics of laboratory blood parameters, as well as the morphological characteristics of the healing of experimental burn wounds when using bacterial cellulose (BC) wound dressings compared to traditional treatment. Materials and methods. 60 rats of both sexes of the Wistar breed were studied, in which skin burn of the third degree was simulated in the experiment. The animals were divided into 3 groups, of which group 1 included individuals who used BC-based wound dressing (n = 20) in the treatment of burn wounds, in group 2 (n=20) BC plates were used after exposure to a 1% chlorhexidine solution, and in group 3 (comparisons, n=20) treatment was carried out using the traditional method (daily dressings with Levomekol ointment). On the fifth, 10th, 15th, 20th, and 28th days, blood was taken from 5 animals to determine the detailed analysis, the main biochemical constants, and the wound tissue was excised for morphological and morphometric evaluation according to the developed criteria. Results. When analyzing laboratory blood parameters, an increase in hemoglobin level was noted, more pronounced in group 3, which is associated with blood clotting due to experimental burn injury. There is a more significant decrease in platelets in group 3 by the end of the study, which characterizes the process of consumption in the open management of an infected burn wound. In groups 1 and 2, compared with traditional treatment in group 3, differences were noted, consisting in a more effective restoration of hemoglobin levels, a decrease in the level of leukocytes, alanine transaminase, and a decrease in azotemia (p<0,05). According to the morphological and morphometric criteria for the healing of burn wounds on days 20 and 28, in 18 (90%) out of 20 rats of groups 1 and 2, the wounds were at the stage of almost complete epithelialization (criterion 4), while in the comparison group this was noted only in 4 (40 %) out of 10 individuals (p<0,01), and in 60% the wounds were in the stage of initial or moderate epithelialization (criteria 2 and 3).

Healing Efficacy of Hesperetin-Containing Chitosan Gel in Burn Wound: Formulation Design and In Vivo Evaluation

More than 5 million people require medical attention due to burn-related injuries annually. Significant research has been carried out in recent decades to develop approaches to improve the healing of burn wounds. The focus has also been on the development of natural product-based therapeutic remedies for the treatment of burn wounds. This has been done primarily due to multimodal mechanisms exhibited by some promising bioactive molecules of natural origin. Hesperetin is one such molecule that possesses strong anti-inflammatory and antioxidant properties. It is mainly obtained from citrus species. The goal of the current study was to assess how well chitosan gel that contains hesperetin may cure burn wounds. The advantage of using chitosan gel is that it could form a depot at the site and provide a protective therapeutic covering over burn wounds. In the present study, hesperetin-containing chitosan gel was prepared and evaluated for percentage hesperetin content, extrudability, spreadability, and rheological behavior. The preclinical wound healing activity was evaluated using an experimental burn wound model in Wistar rats. The results of the animal experiment showed early and better healing of burn wounds in animals treated with hesperetin-containing chitosan gel. There was 92.79% healing after 14 days of application of hesperetin-containing chitosan gel compared to 69.49% healing observed in the control group. Further, the histopathological evaluation suggested no inflammatory cell infiltration, normal epidermal growth, and normal collagen bundle arrangement in these animals. Overall the results provide proof of concept to establish the wound healing potential of hesperetin-containing chitosan gel against burn wounds.

Estimation of Effectiveness of Local Reactive Oxygen Species for Stimulation of Regenerative Processes in Experimental Burn Wound

The aim of this work was the comparative estimation of the efficiency of different variants of local ozone therapy in experimental burn wound. We conducted the experiments on 45 white Wistar rats being randomized for three groups. Every rat got contact thermal trauma (III degree; 20 bsp) of dorsal body surface on the area 20%. Rats of the first group received a Levomecol treatment of wound, animals of the second group were locally treated by ozonized oil, and the third group rats received a combination of ozone and oxygen gas mixture intracutaneously, and the wounds were treated with Levomecol locally. The character and particularities of post-traumatic regeneration were studied by histological investigation. Local treatment with reactive oxygen species at an early period after burning is revealed to lead to more pronounced manifestation of reparative processes in burn wounds (production of granulation tissue, epidermis regeneration) than when applying Levomecolointment, and that is accompanied by more pronounced initial manifestation of scab rejection. Applying reactive oxygen species in ointment compositions at these stages of treatment with the conjuncture of infected wounds does not contribute marked initiation of reparative processes and can even force the inflammation processes.

Burn inducing device with temperature control to generate experimental cutaneous burn wounds in animal models

Extensive research is being carried out to replicate different aspects of burn injury, understand the unique pathophysiology as well as to develop novel treatment modalities for the burn wounds. Adequate research using different burn models thus play a major role in the development of novel treatments. One of the major constraints in burn animal model is a lack of reproducible burn inducing device which could be used for producing uniform burn wounds. Here we have developed simple, reproducible burn inducing device with temperature control for the creation of uniform burn wounds in animal models.

Efficacy of stromal vascular fraction and enzyme-free mechanical isolation therapy in experimental full thickness burn wounds

Background Autologous cell suspensions obtained by a stromal vascular fraction (SVF) and enzyme-free mechanical isolation (EMI) are an alternative in the treatment of burn wounds. In this study, we aimed to investigate the effect of autologous cell suspensions obtained by SVF and EMI on full-thickness skin burn wounds. Methods A total of 45 male Sprague–Dawley rats were divided into three groups, SVF group, EMI group, and SVF + EMI group. The groups were also classified as the first, second, and third week of the burn to reveal the effect of the treatment on the burn in the early, middle, and late stages. For treatment, 0.2 ml SVF or 0.2 ml EMI was injected subcutaneously into the burn lesions of the subjects. Histopathological examination was performed on the burn wounds taken at the end of the experiment, and Ki67, CD44, CD73, CD90, and CK17 expressions were evaluated. Results Histological examination revealed that there was no improvement in the control samples, but the skin was multicellular, vascularization was present. Histologic scores in all groups was significantly better than control, and SVF + EMI was the best group in terms of recovery (p < 0.05). Ki67, CK17, CD44, CD73, and CD90 expressions were significantly higher in the treatment groups compared to the control (p < 0.05). Conclusion We found in our study that both applications significantly increased the healing of the burn wound. Moreover, SVF + EMI application provided more improvement than SVF or EMI alone.

Wound-healing effect of Platycodon grandiflorus (Jacq.) extract in rats

Purpose: To evaluate the healing effect of Platycodon grandiflorus (Jacq.). extract (PGE) on experimental burn wounds in rats.&#x0D; Methods: Rats were randomly divided into four groups of eight rats each: control group, silver sulfadiazine (SSD)-treated group, moist exposed burn ointment (MEBO)-treated group and PGE-treated group. PGE, SSD and MEBO were applied topically twice daily for 7 days. SSD and MEBO were used as reference control. External observation of wound area contraction and histological analysis of wound tissues was performed respectively. The effect of PGE on matrix metalloproteases (MMPs), vascular endothelial growth factor (VEGF) and Type-III Collagen proteins of wound tissue in rats were analysed by Western blot.&#x0D; Results: After 10 days of topical treatment with PGE, PGE-treated group showed faster reduction in wound area when compared with control groups (p &lt; 0.01). Matrix metalloprotease-2 (MMP-2), matrix metalloprotease-9 (MMP-9), VEGF and type-III collagen expressions in the wound tissue increased significantly (p &lt; 0.05) when compared with the control burn wounds. Histological results showed an overall early recovery and regeneration in PGE-treated group when compared with control group.&#x0D; Conclusion: PGE possesses a significant wound-healing activity in full-thickness burn wounds in rats. Therefore, it can potentially be developed for the management of burns.

Carboxymethyl chitosan hydrogel formulations enhance the healing process in experimental partial-thickness (second-degree) burn wound healing.

ABSTRACTPurposeThis study aimed to elaborate a hydrogel constituted by carboxymethyl chitosan (CMC), hyaluronic acid (HA) and silver (Ag) and to evaluate its healing effect on partial-thickness burn wounds experimentally induced in rats.MethodsCMC was obtained by chitosan reacting with monochloroacetic acid. The carboxymethylation was confirmed by Fourier-transform infrared spectroscopy and hydrogen nuclear magnetic resonance (NMR). Scanning electron microscopy was used to determine the morphologicalcharacteristics of chitosan and CMC. After the experimental burn wound induction, the animals (n = 126) were treated with different CMC formulations, had their occlusive dressings changed daily and were followed through 7, 14 and 30 days. Morphometric, macroscopic and microscopic aspects and collagen quantification were evaluated.ResultsSignificative wound contraction, granulation tissue formation, inflammatory infiltration and collagen fibers deposit throughout different phases of the healing process were observed in the CMC hydrogels treated groups.ConclusionsThe results showed that, in the initial phase of the healing process, the most adequate product was the CMC/HA/Ag association, while in the other phases the CMC/HA association was the best one to promote the healing of burn wounds.

Effectiveness of maggot extractions and secretion (E/S) of Lucilia sericata in reducing wound surface in experimental scalding burn injury

Abstract. Amiri ZS, Akbarzadeh K, Douraghi M, Abdi KM, Afshar AA, Ghaffari J, Kordshouli RS, Akbari M, Rafinejad J. 2021. Effectiveness of maggot extractions and secretion (E/S) of Lucilia sericata in reducing wound surface in an experimental scalding burn injury. Nusantara Bioscience 13: 11-15. Lucilia sericata larvae have been successfully used as medicinal larvae for wound healing. This study was performed to evaluate the therapeutic effects of the primary ointment made from excretory-secretory substances of L.sericata larvae on experimental burn wounds on rabbits under laboratory conditions. Extraction of ES from the third stage of L.sericata larvae and antibiogram testing was done. Four rabbits were randomly divided into four groups; three standard third-grade burn wounds were created on the back of each rabbit for intervention groups (B, D) of wounds were used respectively from the original ointment made from ES and ES without accompanying material. Nitrofurazone ointment was used for the positive (C) and placebo ointment was used for the negative (A). On the 21st day, all scars of wounds in groups B and D were separated and the wound was free of infectious tissue, whereas in groups A and C that the scars were clinging to the base. The level of the ulcer was significantly lower in the E/S intervention group and the infectious tissue was not observed during the treatment of group B and D wounds. Methicillin-resistant Staphylococcus aureus (MRSA) did not show resistance to excretory-secretory substances of L. sericata larvae. The debridement and recovery process was faster in the ES-treated group and the initial ointment than in the control group. The results showed that maggot extractions and secretion (E/S) of L. sericata in reducing wound healing is appropriate for treatment.

Does the use of topical honey result in a faster rate of second intention wound healing in dogs?

PICO question&#x0D; In healthy dogs undergoing open wound management, does the topical application of honey, when compared to wounds treated with daily saline washes only, reduce the time to complete wound healing?&#x0D; &#x0D; Clinical bottom line&#x0D; Category of research question&#x0D; Treatment&#x0D; The number and type of study designs reviewed&#x0D; Two studies satisfied the inclusion criteria for answering the PICO; both were prospective randomised controlled trials&#x0D; Strength of evidence&#x0D; Weak&#x0D; Outcomes reported&#x0D; The studies demonstrated a possible effect size of clinical importance of the use of honey in the treatment of canine wounds in terms of time to complete wound healing and antibacterial effect. However, the strength of the evidence provided by both studies is severely weakened by flaws in trial design, implementation and reporting, and the possible risk of pseudo replication between the two trials reported&#x0D; Conclusion&#x0D; The use of topical honey in canine open wound management may reduce time to complete wound healing. However, the evidence for this is weak. At present, the evidence that use of topical honey in canine wounds reduces time to healing is insufficient to warrant a change in clinical practice&#x0D; &#x0D; How to apply this evidence in practice&#x0D; The application of evidence into practice should take into account multiple factors, not limited to: individual clinical expertise, patient’s circumstances and owners’ values, country, location or clinic where you work, the individual case in front of you, the availability of therapies and resources.&#x0D; Knowledge Summaries are a resource to help reinforce or inform decision making. They do not override the responsibility or judgement of the practitioner to do what is best for the animal in their care.&#x0D; &#x0D; Editorial notice: Upon conducting the literature search for this Knowledge Summary the author discovered that the same paper had been published in two separate journals and that a third paper by the same author appeared to have used data from the same experimental subjects as the duplicate publication, despite reporting different methodology. The duplicate publications have been appraised by the author as one paper. The editorial office alerted the journals in question which resulted in the article that appeared in the Iranian Journal of Veterinary Surgery (Jalali, F.S. S., Tajik, H., Saifzaideh, S and Fartash, B. (2007b) Topical Application of Natural Urmia Honey on Experimental Burn Wounds in the Dog: Clinical and Microbiological Studies. Iranian Journal of Veterinary Surgery. 2(2), 13–21) being retracted: http://www.ivsajournals.com/article_114759.html. See our own policy on duplicate publication for more information.&#x0D; &#x0D;

Characterization of a Topically Testable Model of Burn Injury on Human Skin Explants.

Severe burn injuries remain a major health problem due to high rates of mortality, residual morbidity, and/or aesthetic damages. To find new therapies aimed at promoting a harmonious healing of skin burns, it is important to develop models which take into account the unique properties of the human skin. Based on previously described models of burn injury performed on human skin explants, we hypothesized that maintaining explants under constant tension forces would allow to more closely reproduce the pathophysiological processes of skin remodeling. We thus. Here, we set up and characterized an improved model of deep second-degree burn injury on ex vivo cultured human skin explants at air-liquid interface and maintained under conditions of constant tension forces. A spontaneous re-epithelialization of the lesion was observed 8 to 9 days post burn and was found to rely on the proliferation of basal keratinocytes at the wound edges. Collagen VII at the dermo-epidermal junction reformed along with the progression of re-epithelializatio and a synthesis of procollagen III was observed in the dermis at the wound site. These findings indicate that our model is suitable for the assessment of clinically-relevant therapies aimed at modulating the kinetics of re-epithelialization and/or the activation of fibroblasts following skin burn injuries. In this regard, we evaluated the use of a thermoreversible poloxamer hydrogel as a vehicle for topically-testable therapeutic molecules. Our data showed that, although useful for drug formulation, the p407/p188 poloxamer hydrogel induces a delay of skin re-epithelialization in humans skin explants submitted to experimental burn injury.

The effect of Myrtus communis L. ethanol extract on the small intestine and lungs in experimental thermal burn injury.

Thermal trauma can damage organs away from the skin burn site and lead to multiple organ dysfunction. Following thermal injury, all tissues are exposed to ischemia, and as a result, resuscitation and reperfusion occur during the burning shock. Burn damage starts systemic inflammatory reactions that produce toxins and reactive oxygen radicals that lead to peroxidation. This study aimed to investigate, for the first time, the possible antioxidant effects of Myrtus communis ethanol extract on burn-induced oxidative distant organ injury orally. The thermal trauma was generated under ether anesthesia by exposing the dorsum of rats to 90°C water bath for 10s. 100mg/kg/day Mrytus communis ethanol extract was applied orally for two days. Malondialdehyde (MDA) and glutathione (GSH) levels, glutatinone-S-transferase (GST), superoxidedismutase (SOD) and catalase (CAT) activities were determined to detect the possible antioxidant effects of myrtle on small intestine and lung tissues. Burn damage significantly increased MDA levels in lung and small intestine tissues, and significantly decreased GSH levels, CAT and GST activities in the small intestine and lung tissues compared to control group. Mrytus communis ethanol extract decreased MDA level and increased GSH level, SOD, CAT and GST activities significantly in either small intestine or lung tissues. Mrytus communis extract may be an ideal candidate to be used as an antioxidant adjunct to improve oxidative distant organ damage to limit the systemic inflammatory response and decreasing the recovery time after thermal injury.

A Murine Model of a Burn Wound Reconstructed with an Allogeneic Skin Graft.

Trivial superficial wounds heal without complications by primary intention. Deep wounds, such as full thickness burns, heal by secondary intention and require surgical debridement and skin grafting. Successful integration of the donor graft into a recipient wound bed depends on timely recruitment of immune cells, robust angiogenic response and new extracellular matrix formation. The development of novel therapeutic agents, which target some key processes involved in wound healing, are hindered by the lack of reliable preclinical models with optimized objective assessment of wound closure. Here, we describe an inexpensive and reproducible model of experimental full thickness burn wound reconstructed with an allogeneic skin graft. The wound is induced on the dorsum surface of anaesthetized inbred wild type mice from the BALB/C and SKH1-Hrhr backgrounds. The burn is produced using a brass template measuring 10 mm in diameter, which is preheated to 80 °C and delivered at a constant pressure for 20 s. Burn eschar is excised 24 hours after the injury and replaced with a full thickness graft harvested from the tail of a genetically similar donor mouse. No specialized equipment is required for the procedure and surgical techniques are straightforward to follow. The method may be effortlessly implemented and reproduced in most research settings. Certain limitations are associated with the model. Due to technical difficulties, the harvest of thinner split thickness skin grafts is not possible. The surgical method we describe here allows for the reconstruction of burn wounds using full thickness skin grafts. It may be used to carry out preclinical therapeutic testing.

Healing Properties of Epidermal Growth Factor and Tocotrienol-Rich Fraction in Deep Partial-Thickness Experimental Burn Wounds.

Background: An experimental study was undertaken to determine the efficacy of the epidermal growth factor (EGF) with tocotrienol-rich fraction (TRF) cream in the wound-healing process on skin with deep partial-thickness burn in rats. Methods: A total of 180 Sprague-Dawley rats were randomly divided into six groups of six each and were: untreated control, treated with Silverdin® cream, base cream, base cream with c% EGF, base cream with 3% TRF or base cream with c% EGF and 3% TRF, respectively. Creams were applied once daily for 21 consecutive days. Six animals from each group were sacrificed using anaesthetic overdose on the third, seventh, 11th, 14th and 21st day post-burn. Skin tissues with the wound to be examined were excised for macroscopic and microscopic evaluation and biochemical analyses. Results: EGF + TRF formulation decreased the number of neutrophils, lymphocytes and myofibroblasts post-burn. However, no effects on the number of adipose cells in the healing process were recorded. In addition, lipid peroxidation and nitrite production were found to be reduced post-burn, reducing oxidative stress. Conclusions: Results of the present study indicate that the addition of EGF with TRF have ameliorating effects on deep-partial thickness burn healing parameters.

The effect of magnetic field therapy and electric stimulation on experimental burn healing.

: In this study, we aimed to compare morphological and histological differences between magnetic field and electric stimulation therapies in an experimental burn injury model in rats. Between February 2011 and July 2011, a total of 21 Sprague-Dawley female rats were used in this study. Second-degree burns were induced on the back areas of the rats. All rats were equally divided into three groups including seven in each: the first burn group was treated with antibacterial pomade (Group 1, control group); the second group was treated with both antibacterial pomade and pulsed electromagnetic field therapy (Group 2); and the third group was treated with antibacterial pomade and electric stimulation for 14 days (Group 3). Earlier re-epithelialization, wound area contraction, reduction of edema, and hyperaemia were observed on gross examination in the pulsed electromagnetic fields and electric stimulation therapy groups compared to the control group. Neovascularization, collagen density, granulation tissue formation, cell proliferation, and inflammatory cell response of the pulsed electromagnetic fields and electric stimulation group increased, compared to the control group, in the histopathological evaluation (p<0.05). Our study results showed the positive healing effects of electric stimulation and pulsed electromagnetic fields on burn injury. Pulsed electromagnetic fields therapy produced more positive signs of healing than the electric stimulation group.