Thermal Burn Model Research Articles

A novel, reverse-phase-shifting, thermoreversible foaming hydrogel containing antibiotics for the treatment of thermal burns in a swine model – A pilot study

BackgroundThis study compared a novel topical hydrogel burn dressing (CI-PRJ012) to standard of care (silver sulfadiazine) and to untreated control in a swine thermal burn model, to assess for wound healing properties both in the presence and absence of concomitant bacterial inoculation. MethodsEight equal burn wounds were created on six Yorkshire swine. Half the wounds were randomized to post-burn bacterial inoculation. Wounds were subsequently randomized to three treatments groups: no intervention, CI-PRJ012, or silver sulfadiazine cream. At study end, a blinded pathologist evaluated wounds for necrosis and bacterial colonization. ResultsWhen comparing CI-PRJ012 and silver sulfadiazine cream to no treatment, both agents significantly reduced the amount of necrosis and bacteria at 7 days after wound creation (p < 0.01, independently for both). Further, CI-PRJ012 was found to be significantly better than silver sulfadiazine (p < 0.02) in reducing bacterial colonization. For wound necrosis, no significant difference was found between silver sulfadiazine cream and CI-PRJ012 (p = 0.33). ConclusionsCI-PRJ012 decreases necrosis and bacterial colonization compared to no treatment in a swine model. CI-PRJ012 appeared to perform comparably to silver sulfadiazine. CI-PRJ012, which is easily removed with the application of room-temperature water, may provide clinical advantages over silver sulfadiazine.

Study of the Effectiveness of Drugs Based on Molecular Complexes of Adenosine-polymer on the Model of Thermal Burn

Introduction. In modern pharmacology, more and more widely used molecular complexes (MC) based on donor-acceptor or, on weaker, intermolecular interactions, to stabilize dosage forms in the composition of pharmaceutical substances or their targeted delivery. This trend is actively developing, because the molecules forming MK, which has a certain composition and spatial structure, are preserved and can be released unchanged. The use of MC in tandem with "classical" metal-containing coordination compounds, which enhance or modify the action of the active component, allows the development of new, more effective drugs with optimized bioavailability and activity.Aim. Evaluation of the wound-healing effect of new substances based on aqueous systems containing coordination compounds of copper(II) or zinc with MC adenosine-copolymer of N-vinylpyrrolidone, in comparison with the drug Depantol® on a model of thermal burn in mice.Materials and methods. Mononuclear alainate complexes Cu(Ala)2 · H2O and Zn(Ala)2 (Ala – alainate-anion), copolymer of N-vinylpyrrolidone with crotonic acid (PVP-CA) have been synthesized. The composition of the obtained compounds was confirmed by the data of elemental analysis on a CHN (S) analyzer LECO CHNS (O) 932 (Elemental Microanalysis Ltd, Great Britain). IR spectra of the samples were recorded on a IRAffinity-1 (Shimadzu, Japan) instrument (by tabletting a sample with KBr) and a IRTracer-100 (Shimadzu, Japan) instrument equipped with a Specac Quest ATR attachment (Shimadzu Corporation, Japan). Potentiometric titration of the functional groups of the VP copolymer was performed using a PP-20 pH meter (Sartorius AG, Germany). The solutions of the preparations were prepared by dissolving PVP-KK in polyethylene glycol (PEG-400), followed by the addition of an aqueous dispersion of adenosine (Ad) and the corresponding complex of copper(II) or zinc into the preparation. After modeling a thermal burn of the third degree, the overall mortality in the groups and the dynamics of healing of the injured area were assessed. During the experiment, histological studies of areas of damaged tissue after staining of preparations with hematoxylin and eosin were carried out and a generalized scoring assessment of the characteristics of the burn process was carried out, including an assessment of the width and depth of the formed scar tissue, the severity of inflammatory infiltration and the presence of hemosiderosis in the tissues.Results and discussion. The formation of the MC of the copolymer of N-vinylpyrrolidone with crotonic acid with adenosine made it possible to prepare solutions of preparations containing up to 5 % (wght.) Of the latter. In the obtained samples, the molar ratio of PVP-CA : Ad : M(Ala)2 was 100 : 10 : 1 (M = CuII, Zn), the pH level of the obtained preparations was 7.0–7.1. The resulting funds were applied to the damaged area of the skin in a volume of 0.1 ml/day, each individual, daily for 4 weeks. Introductory substances based on MC PVP-CA : Ad : M(Ala)2 showed a moderate wound healing effect in comparison with the drug Depantol®, based on a water-fat emulsion. Substances that do not contain a metal complex and contain Cu(Ala)2 showed better efficiency in the dynamics of healing a burn injury in comparison with other studied substances, which was combined with a low mortality rate of experimental animals in these groups (3 cases and 2 cases out of 9 individuals, respectively). The reference drug – Depantol®, in turn, showed the best result, probably due to the content in its composition, in addition to dexpanthenol, which is characterized by a wound-healing effect, chlorhexidine antiseptic, and a fatty base, which reduces the dehydration of the injured area.Conclusion. Experimental substances based on aqueous solutions of adenosine-polymer MK showed a moderate wound healing effect comparable to the reference drug, which, however, is of sufficient interest for further study of such compositions, or their modified versions with the addition of antimicrobial components on thermal burn models, in order to creation of new, more effective drugs for the healing of wound surfaces.

Low-Temperature Storage of Placenta Affects Anti-Inflammatory and Wound Healing Properties of Its Extracts

Here we have studied the effect of low-temperature storage of the placenta at different temperatures on anti-inflammatory activity of its extracts in cell models of erythrocyte thermohemolysis and adenosine-5’-diphosphate-induced platelet aggregation. The wound-healing effect of cryopreserved placental extracts was also evaluated in rat thermal burn model. When preserving placenta for up to a month, the temperature of storage was shown to cause no significant impact on the percentage of inhibition of erythrocyte thermohemolysis and platelet aggregation by the extracts. Placental storage for three months at –20°C decreased anti-inflammatory activity of its extracts, and led to its complete loss during 6 months. Placental cryopreservation at –196°C enabled to preserve the anti-inflammatory and wound-healing activity. The cryopreserved placenta-derived extracts showed a pronounced positive effect on reparative process at third-degree (B) skin burn injury in rats.

Estimation of the repair efficiency of collagen matrices on the model of thermal burn

Background. In the world, dozens of new local wound healing agents are developed and improved every year, which undergo preliminary tests on laboratory animals due to the presence of common phases of the course of the wound process with humans.The aim of the study was to evaluate the wound healing effect of matrices obtained on the basis of the recycling of collagen-containing waste.Materials and methods. Collagen matrices are obtained from substandard leather raw materials subjected to treatment with fermented milk composition (KM1) and lactic acid (KM2). The wound healing effect was studied on the model of thermal burns on Wistar rats in 5 groups: 1st – control (natural wound healing); 2nd – experimental 1 (processing KM1); 3rd – experimental 2 (processing KM2); 4th – experimental 3, comparison group (“Levomekol”) and 5th – intact animals (normal, without burns). Wound healing was assessed by the results of planimetry on days 1, 3, 5, 7, 9, and 13 and by histological analysis of the skin tissue on days 6, 13, and 20. On days 6 and 13, the summary antioxidant activity, the total content of leukocytes, erythrocytes, the activity of the catalase enzyme, and the content of malondialdehyde were determined in the blood of rats.Results. With thermal damage to the skin, an IIIA degree burn was formed, accompanied by the development of dry coagulation necrosis. The use of collagen matrices restored the total content of leukocytes, reduced the area of the burn wound, normalized the content of malondialdehyde, the total antioxidant activity and the activity of catalase in the blood. Histomorphometric studies have confirmed the dynamics of skin tissue recovery after a burn. The effectiveness of the use of matrices was comparable to the pharmacopoeial drug “Levomekol”. A higher wound healing effect was noted when using the KM1 matrix.Conclusion. On the model of thermal burn, the wound-healing effect of collagen matrices was established, as evidenced by the results of restoring the number of leukocytes, reducing the area of the burn wound and restoring the histostructure of the skin. One of the molecular and cellular mechanisms of wound healing is the inhibition of lipid peroxidation reactions and the restoration of the antioxidant potential of the body.

Efficacy of extracts from cryopreserved placenta on third-degree burns in rats

Human placenta extracts have anti-inflammatory, antioxidant and wound-healing properties, so they are promising drugs for the treatment of wounds of various origins, including burns. Cryopreservation methods are widely used to preserve the biological activity of placental drugs for a long time. The aim of this work was to study the effect of low-temperature storage of the placenta on the regenerative properties of its extracts. Fragments of freshly obtained placentas were cooled by immersion in liquid nitrogen and stored at –196 °C for 6 months. The placenta was warmed in a water bath at 37 °C. The effect of low-temperature preservation of the placenta on the ability of its extracts to positively affect the wound healing process was studied in a model of thermal burn of III B degree in rats. The effectiveness of wound treatment with extracts from cryopreserved placenta was evaluated by planimetric and histological methods at 3, 7, 14, 21 and 28 days after the burn. The activity of antioxidant enzymes in the serum of animals was also determined. superoxide dismutase activity was assessed by inhibition of adrenaline autooxidation in carbonate buffer, catalase activity was assessed by the degree of inhibition of ammonium peroxide formation. It has been shown that the treatment of burns with extracts from cryopreserved placenta helped to accelerate the regeneration processes and the rate of wound healing. The formation of granulation tissue was detected on the 7th day of treatment with extracts, and on the 14th day in the control. The area of burn wounds during treatment with extracts probably differed from the control starting from 14 days after application of the burn. It was found that the dynamics of recovery of catalase activity after burns is probably higher on the 7th day of treatment with extracts. The obtained data testify to the high efficiency of application of placenta stored at low-temperature for the purpose of obtaining extracts from it with preservation of regenerative properties.

Prolonged, High-Fidelity Simulation for Study of Patient Care in Resource-Limited Medical Contexts and for Technology Comparative Effectiveness Testing.

Model development. High-fidelity simulation laboratory. None. We interviewed subject matter experts to identify relevant prolonged casualty care medical challenges and selected two casualty types to further develop our model: a large thermal burn model and a severe hypoxia model. We met with a multidisciplinary group of experts in prolonged casualty care, nursing, and critical care to describe how these problems could evolve over time and how to contextualize the problems with a background story and clinical environment with expected resource availability. Following initial scenario drafting, we tested the models with expert clinicians. After multiple tests, we selected the hypoxia model for refinement and testing with inexperienced providers. We tested and refined this model until two research teams could proctor the scenario consistently despite subject performance variability. We developed a 6-8-hour simulation model that represented a 14-hour scenario. This model of pneumonia evolved from presentation to severe hypoxia necessitating advanced interventions including airway, breathing, and shock management. The model included: context description, caregiver orientation scripts, hourly progressive physiology tracks corresponding to caregiver interventions, intervention/procedure-specific physiology tracks, intervention checklists, equipment lists, prestudy checklists, photographs of setups, procedure, telementor, and role player scripts, business rules, and data collection methods. This is the first standardized, high-fidelity simulation model of prolonged casualty care described in the literature. It may be used to assess caregiver performance and patient outcomes resulting from that performance during a complex, 14-hour prolonged casualty care scenario. Because it is standardized, the model may be used to compare differences in the impact of new technologies upon caregiver performance and simulated patient outcomes..

PHARMACOLOGICAL STUDIES OF THE DENTAL GEL OF COMBINED COMPOSITION

The growing prevalence of periodontal and oral mucosa diseases results in increasing number of people in need of orthopedic treatment due to tooth loss, which, accordingly, requires quality dental care.&#x0D; The aim – is to study the pharmacological action of a new dental drug of combined composition in the form of a mucoadhesive gel under the conditional name "Cholident" for the treatment and prevention of inflammatory diseases of the periodontium, oral mucosa and to facilitate adaptation to removable dentures.&#x0D; Material and Methods. The study of antiexudative activity of the dental gel was performed on a model of carrageenan edema using electronic plethysmometer, manufactured by WPI. As a reference drug, "Kamistad®" gel (STADA Arzneimittel, AG, Germany) was used. Evaluation of the reparative effect of the gel was performed on the model of thermal burn. At light optical research of histologic micronutrients epithelialization, border zone creation, infiltration of inflammatory cells (macrophages) and angiogenesis have been evaluated.&#x0D; Results. After application of the gel under study, the antiexudative effect began to appear after 30 minutes, as evidenced by a decrease in the volume of the affected paw, while a similar effect of the comparison drug was observed only 60 minutes after application to the paw. The study drug also showed a longer action, as the antiexudative effect was still observed 120 min after application, while in the control group there was no decrease in paw volume after 90 min of the experiment. Sustained decrease of the combustion wound area in the animals to which the studied gel was applied has been demonstrated. Activation of epithelial proliferation in the border area, increase in the height of regenerating epidermis and formation of a thin layer of cells in the combustion area, signs of demarcation zone formation, and increase in density of newly formed vessels in the border zone dermis have been revealed by the results of histological examination.&#x0D; Conclusions. The results show that the studied gel has a moderate anti-inflammatory effect, which in severity and duration of action exceeds the comparison drug, reduces the local inflammatory response and promotes skin regeneration in the acute phase of combustion.

Изучение эффективности липофильного экстракта травы Achillea collina J. Becker ex Reichenb на модели термического ожога у крыс

Цель исследования – изучить эффективность липофильного экстракта травы тысячелистника холмового Achillea collina J. Becker ex Reichenb (ЛЭТП) на модели термического ожога у крыс. Исследования проводили на 40 белых беспородных крысах обоего пола массой 200–240 г. Термический ожог моделировали контактным способом под легким эфирным наркозом. Исследуемый ЛЭТП и референтный препарат – мазь с маслом облепихи наносили на раневую поверхность 1 раз в сутки в течение 50 сут. Ранозаживляющую активность оценивали по таким показателям, как ликвидация перифокальной реакции, отторжение струпа, появление грануляции, начало краевой эпителизации, скорость полной эпителизации. В сыворотке крови твердофазным иммуносорбентным сэндвидж методом ELISA определяли маркеры окислительного стресса (нитротирозин) и воспаления (С-реактивный белок, интерлейкин-1b). В ходе эксперимента на крысах с моделью термического ожога установлено, что ЛЭТП и мазь с маслом облепихи оказывали значительное ранозаживляющее действие, ускоряя темпы регенерации. Полное заживление ожоговой раны под влиянием ЛЭТП и мази с маслом облепихи наступало на 24–26 сут по сравнению с 46 сут в контрольной группе животных. В случае применения ЛЭТП и мази с маслом облепихи содержание нитротирозина в сыворотке крови уменьшалось на 43,2 и 47,0 %, С-реактивного белка – на 47,3 и 24,8 %, интерлейкина-1b – на 54,3 и 26,2 % соответственно по сравнению с показателями контрольной группы. Полученные результаты экспериментально обосновывают наличие ранозаживляющей активности ЛЭТП и позволяют рекомендовать его как перспективное лекарственное сырье для производства компонентов фитопрепаратов с ранозаживляющей активностью.

Effect of Ligand Peptides on Post-Burn Inflammation of Damaged Corneal Tissue in Experiment

Background. In case of a corneal burn injury, cell transplantation into the damaged area must be performed within the first 12 hours, which makes it impossible to use autologous stem cells. One solution to this problem may be the use of peptides, derived from cultured stem cells in the treatment and prevention of complications in a burn eye disease. Aims: To study the dynamics of corneal tissue repair under the influence of a peptide solution on a corneal thermal burn model.Materials and methods. The study included 20 rabbits (20 eyes) of the gray Chinchilla breed weighing from 2.5 to 3.2 kg with a corneal thermal burn model. Depending on the method of treatment used, the animals were divided in two groups of 10 rabbits (10 eyes). In the experimental group, instillations of a peptide solution were used to treat corneal thermal burns; in the control treatment was carried out with a solution of moxifloxacin and gel “Solcoseryl”. On the 1st, 3rd, 7th, 14th, 30th days in each group, two animals were sacrificed to conduct a morphological study of the cornea. Results. In the experimental group, by the 30th day, according to a histological study, the inflammatory process was completed both on the surface and inside the cornea, with a tendency to restore its normal structure. In the control group of animals, significantly longer periods of corneal recovery and preservation of inflammation, despite the received therapy, were observed.Conclusions. The use of the peptide preparation is promising in the treatment of corneal thermal burn. Further research is needed in this area.

Hydrosurgical debridement as an approach to wound healing: an animal thermal burn model.

This study investigates the advantages of hydrosurgical debridement compared with surgical debridement. Thermal skin burns were created on the backs of male Wistar rats. Surgical debridement was used to treat one wound and hydrosurgical debridement (Versajet Hydrosurgery System, Smith&Nephew, UK) used to treat the second wound. Debridement time, blood loss volume, time-to-heal and histologic changes in the wound areas were compared. A total of 23 rats were used in the study. Debridement time and time-to-heal were significantly shorter with hydrosurgical debridement than with surgical debridement (p<0.01 and p<0.05, respectively). Blood loss volume was significantly less with hydrosurgical debridement (p<0.01), and the wound surface area was significantly smaller on days two (p<0.01), four (p<0.05) and seven (p<0.05). Dense inflammatory cell infiltration into dermal muscle was deeper after surgical debridement (p=0.017). Reactive fibrotic tissue at the wound surface was significantly thinner (p<0.001) and the vascular endothelial cell count was significantly higher (p<0.001) after hydrosurgical debridement. The hydrosurgical system used appears to provide for minimally invasive debridement that can be performed in a relatively short period of time. Use of the device appears to minimise injury to healthy tissue and ameliorate inflammation, which in turn promotes early wound healing and reduces scar contracture. Hydrosurgical debridement appears to cause less damage to normal tissues. Furthermore, it is easier and requires less time.

A new model for standardising and treating thermal injury in the rat

Thermal burn injury methodologies are inconsistently described within the current literature. To permit the advancement of new treatments there is an urgent need for the development and standardisation of an acute rat model. We describe a rat thermal burn model that involves: anaesthesia, chronic catheterisation, skin preparation, baseline hemodynamic and physiological monitoring, and a quantifiable method to reproduce a severe full-thickness burns injury affecting ∼30% percent of the total body surface area (%TBSA). Following a 15 min post-burn period, treatment commences with an acute monitoring phase lasting up to 8 h, which can be modified according to individual protocols. This model reflects the clinical continuum-of-care from point-of-injury, a 15 min ambulance response time, a 60 min prehospital phase and hospital treatment monitoring phase. The model is validated with histological evidence of full-thickness injury, evidence of the hypermetabolic response (K+, Base Excess, lactate) and changes in complete blood counts.•It has been 50 years since Walker and Mason published their widely popular “A Standard Animal Burn Model”.•The model, however, lacks quantifiable methodology for the assessment of burn thickness, surface area burnt and physiological status.•We present a new standardised method for evaluation of drug and interventional therapies that mimic the clinical scenario including ambulance response, pre-hospital and hospital phases after burn.

The effect of the new combined cream on the protein synthetic activity of cells on the model of the thermal skin damage in rats

Aim. To study the mechanisms of the reparative action of a new combined cream on the model of thermal burn injury in rats.Materials and methods. On the model of thermal burn in rats the reparative properties of the new combined cream under the conditional name “Dermalipoin” containing α-lipoic acid, urea, olive oil, tea tree oil, PEG-400 were studied. To determine the level of the protein synthetic activity of cells (epitheliocytes of the stratified squamous epithelium in the epidermis and cells of the fibroblast cell in the edges of healing of thermal damage) the content of ribonucleoproteins (RNP) in the cytoplasm and deoxyribonucleoproteins (DNP) in the nuclei of the cells was assessed by the cytometric method.Results and discussion. On the model of thermal burn in rats “Dermalipoin” cream showed a more active effect on reparative processes compared to the reference drugs – methyluracil ointment and “Titriol” gel. It indicates a significant increase in the protein synthetic function of epitheliocytes of the stratified squamous epithelium in the epidermis and cells of the fibroblastic series at the healing edges. The reparative activity of the cream was, first of all, provided by the presence of thiol (sulfhydryl) groups in the molecule of lipoic acid, giving it the properties of an antioxidant. The antioxidant effect of lipoic acid promotes more efficient DNA molecule reparation after damage as a result of the oxidative stress.Conclusions. “Dermalipoin” cream shows a marked reparative effect due to the increase of the protein synthetic activity and acceleration of reparation of DNA molecules of epithelial cells after damage; as a result, the process of healing burns accelerates.

Heparin mimetic peptide nanofiber gel promotes regeneration of full thickness burn injury

Burn injuries are one of the most common types of trauma worldwide, and their unique physiology requires the development of specialized therapeutic materials for their treatment. Here, we report the use of synthetic, functional and biodegradable peptide nanofiber gels for the improved healing of burn wounds to alleviate the progressive loss of tissue function at the post-burn wound site. These bioactive nanofiber gels form scaffolds that recapitulate the structure and function of the native extracellular matrix through signaling peptide epitopes, which can trigger angiogenesis through their affinity to basic growth factors. In this study, the angiogenesis-promoting properties of the bioactive scaffolds were utilized for the treatment of a thermal burn model. Following the excision of necrotic tissue, bioactive gels and control solutions were applied topically onto the wound area. The wound healing process was evaluated at 7, 14 and 21 days following injury through histological observations, immunostaining and marker RNA/protein analysis. Bioactive peptide nanofiber-treated burn wounds formed well-organized and collagen-rich granulation tissue layers, produced a greater density of newly formed blood vessels, and exhibited increased re-epithelialization and skin appendage development with minimal crust formation, while non-bioactive peptide nanofibers and the commercial wound dressing 3M™ Tegaderm™ did not exhibit significant efficiency over sucrose controls. Overall, the heparin-mimetic peptide nanofiber gels increased the rate of repair of burn injuries and can be used as an effective means of facilitating wound healing.

The Regenerative Effects of Hemostatic Plant Extract in Second Degree Burn Wound

Introduction: The effects of Ankaferd Blood Stopper (ABS), a hemostatic herbal agent, on wound healing of experimental second degree thermal burn model were analyzed in this study. Material and Methods: 24 wistar albino rats were used. All rat subjects were divided into 4 equal groups as control, burn control, Ankaferd Blood Stopper and serum physiologic. In all rats except for those in negative control group, second degree thermal burn was formed with metal plates heated on their backs. Biopsies were taken on 0th,7th,14th and 21st days. In tissue samples; they were evaluated in terms of fibroblast increase histopathologically, congestion, inflammatory cell increase and epithelization findings and they were also scored. The values obtained were compared statistically. Results: No significant difference was observed between groups with regard to fibroblast increase (p>0.05). On the 7th day, congestion values in burn control group was determined higher than ABS group (p

Antimicrobial blue light inactivation of Candida albicans: In vitro and in vivo studies

ABSTRACTFungal infections are a common cause of morbidity, mortality and cost in critical care populations. The increasing emergence of antimicrobial resistance necessitates the development of new therapeutic approaches for fungal infections. In the present study, we investigated the effectiveness of an innovative approach, antimicrobial blue light (aBL), for inactivation of Candida albicans in vitro and in infected mouse burns. A bioluminescent strain of C. albicans was used. The susceptibilities to aBL (415 nm) were compared between C. albicans and human keratinocytes. The potential development of aBL resistance by C. albicans was investigated via 10 serial passages of C. albicans on aBL exposure. For the animal study, a mouse model of thermal burn infected with the bioluminescent C. albicans strain was used. aBL was delivered to mouse burns approximately 12 h after fungal inoculation. Bioluminescence imaging was performed to monitor in real time the extent of infection in mice. The results obtained from the studies demonstrated that C. albicans was approximately 42-fold more susceptible to aBL than human keratinocytes. Serial passaging of C. albicans on aBL exposure implied a tendency of reduced aBL susceptibility of C. albicans with increasing numbers of passages; however, no statistically significant difference was observed in the post-aBL survival rate of C. albicans between the first and the last passage (P>0.05). A single exposure of 432 J/cm2 aBL reduced the fungal burden in infected mouse burns by 1.75-log10 (P=0.015). Taken together, our findings suggest aBL is a potential therapeutic for C. albicans infections.

Evaluation of skin regeneration after burns in vivo and rescue of cells after thermal stress in vitro following treatment with a keratin biomaterial

Thermal burns typically display an injury pattern dictated by the transfer of the thermal energy into the skin and underlying tissues and creation of three zones of injury represented by a necrotic zone of disrupted cells and tissue, an intermediate zone of injured and dying cells, and a distant zone of stressed cells that will recover with proper treatment. The wound healing capabilities of a keratin biomaterial hydrogel were studied in two pilot studies, one using a chemical burn model in mice and the other a thermal burn model in swine. In both studies, keratin was shown to prevent enlargement of the initial wound area and promote faster wound closure. Interestingly, treating thermally stressed dermal fibroblast in culture demonstrated that soluble keratin was able to maintain cell viability and promote proliferation. Separation of so-called alpha and gamma fractions of the keratin biomaterial had differential effects, with the gamma fraction producing more pronounced cell survival and recovery. These results suggest that the gamma fraction, composed essentially of degraded alpha keratin proteins, may facilitate cell rescue after thermal injury. Treatment of burns with gamma keratin may therefore represent a potential therapy for wounds with an intermediate zone of damaged tissue that has the potential to contribute to spontaneous healing.

Contribution of antioxidant systems to regeneration of tracheal epithelium after burn of upper respiratory tract

Study was performed using a rat model of thermal burn of upper respiratory tract (URT). The URT burn in rats was induced by intratracheal instillation of 70 °C water vapor using a micro-vapor generator. In a week after the intervention about 50 % of the ciliated epithelium was destructed. In 2 weeks after the intervention the inflammatory response enhanced and tissue edema increased. In 4 weeks after the intervention partial irregular restoration of tracheal epithelium cells was observed. Both IL-1 and IL-4 expression did not change significantly during restoration of tracheal epithelium, but IL-8 and IL-10 expression increased and was high even 1 month after the burn. Simultaneously, dramatic increase in expression of peroxyredoxine 6, which is the main antioxidant protein in trachea, was observed during regeneration of trachea epithelium. Iimmunohistochemical investigations showed that the increase in peroxyredoxine 6 in trachea during the regeneration of trachea epithelium after the burn could be related to increased peroxyredoxine expression in goblet cells. Therefore, activation of peroxyredoxine 6 synthesis by goblet cells appears to be the key step in activation of epithelium defense systems after thermal burn.

화상 및 창상에 대한 자근.치자 복합제제의 경피 흡수 및 치료효과

Research was undertaken to compare the pharmacological activity of Lithospermi radix (LR) reported as an oriental medicine for classical uses. LR contains naphthoquinone pigments : shikonin, acetylshikonin, isobutylshikonin, etc. LR is used for the treatment of excision wound, burn, eczema, blister, scarlatina and septicemia as antifebrile, antidotic and antiphlogistic. Gardeniae fructus (GF) has been used for the treatment to jaundice, hepatic disease, anti-inflammatory and analgesic effects, and it contains crocin, geniposide and its derivatives. The therapeutic effects of burn and excision wound healing from LR & GF hydrogel with (GLN) were investigated. To evaluate the therapeutic value of various hydrogels, thermal burn model and excision wound mouse model were used. The burn and wound reduction rate and therapeutic period were measured to calculate the healing extent after 5 experiments. The 2nd degree burn was prepared on hairless mouse back skin and dressing with collagen. The burn and wound reduction rate of GLN hydrogel treated group decreased more rapidly than that of other gel group in animal model. Furthermore therapeutic periods of GLN hydrogel treated group was shorter than that of other gel group. In anti-inflammatory test, GLN hydrogel treated group decreased edema rapidly than that of other gel group. These results suggest that the GLN hydrogel treatment has an therapeutic effect on burn and excision wound healing.

Ascorbic Acid Therapy in a Thermal Burn Model of Corneal Ulceration in Rabbits

We studied the effect of topical and systemic ascorbic acid on a rabbit model of corneal ulceration produced by thermal burn. Central stromal ulceration occurred in 77% to 100% of eyes in all treatment groups. The rate of ulceration was accelerated in animals treated with systemic ascorbic acid. Ulceration began after 5.80 +/- 2.14 days in control eyes and 2.75 +/- 1.26 days in the eyes of rabbits treated with both topical and systemic ascorbic acid (P less than .02). Subconjunctival ascorbic acid alone did not affect the rate of ulceration (average onset, 6 +/- 1 days). Once ulceration occurred in animals treated with both topical and systemic ascorbic acid, the incidence of perforation and descemetocele formation was increased and that of healing was decreased. The time required for healing was not significantly altered by treatment (9.50 +/- 2.28 days for control eyes vs 5.75 +/- 2.78 days for treated eyes) (P greater than .05).