Skin Wounds In Rats Research Articles

Effects of carbon dioxide therapy on the healing of acute skin wounds induced on the back of rats

To evaluate the healing effect of carbon dioxide therapy on skin wounds induced on the back of rats. Sixteen rats underwent excision of a round dermal-epidermal dorsal skin flap of 2.5 cm in diameter. The animals were divided into two groups, as follows: carbon dioxide group - subcutaneous injections of carbon dioxide on the day of operation and at three, six and nine days postoperatively; control group - no postoperative wound treatment. Wounds were photographed on the day of operation and at six and 14 days postoperatively for analysis of wound area and major diameter. All animals were euthanized on day 14 after surgery. The dorsal skin and the underlying muscle layer containing the wound were resected for histopathological analysis. There was no statistically significant difference between groups in the percentage of wound closure, in histopathological findings, or in the reduction of wound area and major diameter at 14 days postoperatively. Under the experimental conditions in which this study was conducted, carbon dioxide therapy had no effects on the healing of acute skin wounds in rats.

The Anti-Scar Effects of Basic Fibroblast Growth Factor on the Wound Repair In Vitro and In Vivo

Hypertrophic scars (HTS) and keloids are challenging problems. Their pathogenesis results from an overproduction of fibroblasts and excessive deposition of collagen. Studies suggest a possible anti-scarring effect of basic fibroblast growth factor (bFGF) during wound healing, but the precise mechanisms of bFGF are still unclear. In view of this, we investigated the therapeutic effects of bFGF on HTS animal model as well as human scar fibroblasts (HSF) model. We show that bFGF promoted wound healing and reduced the area of flattened non-pathological scars in rat skin wounds and HTS in the rabbit ear. We provide evidence of a new therapeutic strategy: bFGF administration for the treatment of HTS. The scar elevation index (SEI) and epidermal thickness index (ETI) was also significantly reduced. Histological reveal that bFGF exhibited significant amelioration of the collagen tissue. bFGF regulated extracellular matrix (ECM) synthesis and degradation via interference in the collagen distribution, the α-smooth muscle actin (α-SMA) and transforming growth factor-1 (TGF-β1) expression. In addition, bFGF reduced scarring and promoted wound healing by inhibiting TGFβ1/SMAD-dependent pathway. The levels of fibronectin (FN), tissue inhibitor of metalloproteinase-1 (TIMP-1) collagen I, and collagen III were evidently decreased, and matrix metalloproteinase-1 (MMP-1) and apoptosis cells were markedly increased. These results suggest that bFGF possesses favorable therapeutic effects on hypertrophic scars in vitro and in vivo, which may be an effective cure for human hypertrophic scars.

Palygorskite organophilic for dermopharmaceutical application

Due to the growing interest of the population in natural treatments, the clays represent a good alternative to the treatment of wounds. Its modification by organophilization happens when the same inorganic cations are exchanged for organic cations of the surfactant used in the process. Thus, the clay has the properties of its surface modified from being hydrophilic to hydrophobic, improving its functionality on the skin. In order to determine changes in surface palygorskite and to assess its healing action, this clay was organophilizated by two cationic surfactants: dimethyl benzyl ammonium chloride alkyl, and cetyl trimethyl ammonium chloride, and characterized by sieve analysis, property flow, test oil adsorption, and the techniques of X-ray fluorescence, X-ray diffraction, infrared Fourier transform, thermogravimetric analysis, scanning calorimetry—differential and histological of cutaneous wounds in rats. The results indicate that the attapulgite has good rheological properties, a high capacity of adsorption of oil, and the presence of clay minerals that reduce inflammation. The analysis by X-ray fluorescence is not observing any change in the crystal structure of palygorskite organophilizated but through infrared spectroscopy Fourier transform, verifying the interaction and incorporation of the clay ammonium salts, as well as thermoanalytical analysis also suggests that the organophilic process reduces the hydrophilic character of palygorskite. The histological analysis showed healing effect after topical application of natural and organophilizated clay in skin wounds in rats. These analyses favor a good prospect of its application in dermopharmaceuticals, because the use of palygorskite provides greater interaction with skin and heals wounds.

Low Level Fluoride Stimulates Epithelial-Mesenchymal Interaction in Oral Mucosa

Oral mucosa consists of the superficial epithelium and the underlying lamina propria, and it functions as a barrier against exogenous substances. In development, interactions of stem/progenitor cells of the epithelium and mesenchyme are crucial to the morphogenesis of oral mucosa. Our previous work in low level fluorideinduced cell motility of epithelial cells has yielded important clues for periodontal physiology. This study focuses on a working concept of low level fluoride to provide a conducive oral environment for pivotal epithelialmesenchymal interactions. Cultured human primary gingival epithelial cells treated with 50 μM NaF were investigated by DNA microarray. Quantitative real-time PCR and an in vivo experimental rat skin wound model were employed to confirm the findings obtained with the microarray analysis. Microarray data revealed that low level fluoride-treated human gingival epithelial cells elevated various biological processes. The key proliferation markers, FGF2 and FGF7, and mesenchymal marker, Twist1, expression was up-regulated and quantitative real-time PCR confirmed this observation. Our in vivo study revealed that low concentration of NaF increased FGF2, FGF7, and Twist1 protein expression in fluoride-treated skin wound tissues compared with controls. These results provide new information on low level fluoride-induced epithelial-mesenchymal interactions and may thus aid in the understanding of oral mucosa development.

Effect of Fibrin-binding Synthetic Oligopeptide on the Healing of Full-thickness Skin Wounds in Streptozotocin-induced Diabetic Rats

The aim of this study was to investigate whether topical application of fibrin-binding oligopeptides derived from FN promotes wound healing in streptozotocin (STZ)-induced diabetic rats. Oligopeptides including fibrin-binding sequences (FF3: CFDKYTGNTYRV, FF5 : CTSRNRCNDQ) of FN repeats were synthesized. Each peptide was loaded in 15 x 15 mm fibrous alginate dressings, and the release kinetics of the peptides was evaluated using trinitrobenzene sulfonic acid for 336 hours. Two full-thickness cutaneous wounds were prepared on the dorsal skin of each 75 diabetes induced rats. Each wound was divided into FF3-loaded alginate dressing group, FF5-loaded alginate dressing group, alginate dressing group and negative control group. Animals were sacrificed at day 0,3,7 and 14. The wound closure rate, inflammation degree, expression of TGF-β1 and hydroxyproline contents were evaluated. Both FF3 and FF5 peptides were released rapidly within the first 24 hours. FF3-loaded dressing treated wounds closed significantly faster than other wounds at day 3. And at day 14, FF3- & FF5- loaded dressing treated wounds demonstrated less inflammatory cells infiltration than alginate dressing treated and negative group wounds. TGF-β1 positive cells were more abundant in FF3-, FF5-treated alginate dressing treated wound at day 3 and 14. At last, the hyrdroxyproline contents in the FF3, FF5 group were higher at day 7 and day 14. Topical application of fibrin-binding domain synthetic oligopeptides from FN resulted in acceleration of full-thickness cutaneous wound healing in diabetic rats.

Tissue-specific patterns of caspase-1 and cytokines in excisional wounds are altered by shock in rat skin and muscle

22 Tissue-specific patterns of caspase-1 and cytokines in excisional wounds are altered by shock in rat skin and muscle Ravi Starzl , Dolores Wolfram , Ruben Zamora , Bahiyyah Jefferson , Derek Barclay , Chien Ho , Gerald Brandacher , Stefan Schneeberger , W.P. Andrew Lee , Jaime Carbonell , Yoram Vodovotz c,d Language Technologies Institute, Carnegie Mellon University, Pittsburgh, PA, USA Department of Plastic and Reconstructive Surgery, Innsbruck Medical University, Innsbruck, Tyrol, Austria Department of Surgery, University of Pittsburgh, Pittsburgh, PA, USA Center for Inflammation and Regenerative Modeling, McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA Department of Plastic and Reconstructive Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA Objectives: Skin and muscle wounds often lead to significant inflammation in the affected tissue. The primary mechanism by which inflammation is initiated, sustained, and terminated is cytokine-mediated immune signaling, but this can be altered by cardiogenic shock. The complexity and context sensitivity of immune signaling in general stymied a clear understanding of these signaling dynamics. We hypothesized that advanced numerical and biological function analysis methods would help elucidate the inflammatory response to skin and muscle wounds in rats, both with and without concomitant shock. Methods: We studied 2 experimental groups: wound only (“wound group”) and wound with cardiogenic shock (“shock group”). In the “wound group,” 4 Lewis rats were anesthetized and an excision biopsy was taken from the lateral aspect of the thigh on one of the hind limbs in each of the rats. In the “shock group,” 4 Lewis rats were sacrificed, and excision biopsy (wound) was carried out 15 to 30 seconds after cessation of heartbeat. Skin and muscle tissue was then separated and assayed for total protein content by BCA assay, and the inflammation biomarkers interferon-γ, interleukin (IL)-1α, IL-1β, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12p70, IL-18, monocyte chemotactic protein (MCP-1), growth-related oncogene/KC, tumor necrosis factor α, and granulocyte-macrophage colony-stimulating factor were assayed by Luminex (Luminex Corp, Austin, TX). Caspase-1, which drives activation of the NLRP-3 inflammasome, was assessed by Western blot assay. Statistical and computational analyses of cytokine network profiles (1-way balanced analysis of variance, unpaired 1-tailed heteroscedastic t test, principal components analysis, and confirmatory factor analysis) were performed in Matlab (The MathWorks, Inc, Natick, MA). Results: Granulocyte-macrophage colony-stimulating factor was elevated in the wound group (P b .05), whereas IL-4, IL-12p70, interferon-γ, and IL-18 were elevated in the shock group (P b .05). Interleukin-1α and IL-18 were more elevated in skin vs muscle (P b .05), which was suggestive of inflammasome activation in the skin. MCP-1, IL-1β, IL-2, IL-6, IL-10, IL-4, IL-12p70, and tumor necrosis factor α (P b .05) were also differentially higher in skin vs muscle. Immunoblotting revealed caspase-1 activation in skin but not muscle. Notably, IL-1α and IL-18, along with caspase-1, were greatly elevated in the skin after cardiogenic shock (P b .05). Principal components analysis suggested that more than 95% of observed variance could be explained by 2 principal components in the skin and muscle and suggested distinct groups of inflammatory mediators induced in the “wound group” vs the “shock group”. Interleukin-18 and IL-1α were primary contributors to the first principal component, whereas IL-6, MCP-1, growth-related oncogene/KC, and IL-1β were primary contributors to the second principal component. Principal components analysis results were reinforced by confirmatory factor analysis. Conclusions: Caspase-1 and the NLRP-3 inflammasome appear to be key factors in determining the type and severity of the inflammatory response to excisional wounding, especially in the presence of shock. Activated caspase-1 is associated with defined, compartmentalized patterns of cytokine production that may be discerned via data-driven modeling. http://dx.doi.org/10.1016/j.jcrc.2012.10.038

Global sensitivity analysis of endotoxin-induced acute inflammatory responses predicts the multimodal dependence of global tissue damage both on host IL-6 responses and endotoxin dose

22 Tissue-specific patterns of caspase-1 and cytokines in excisional wounds are altered by shock in rat skin and muscle Ravi Starzl , Dolores Wolfram , Ruben Zamora , Bahiyyah Jefferson , Derek Barclay , Chien Ho , Gerald Brandacher , Stefan Schneeberger , W.P. Andrew Lee , Jaime Carbonell , Yoram Vodovotz c,d Language Technologies Institute, Carnegie Mellon University, Pittsburgh, PA, USA Department of Plastic and Reconstructive Surgery, Innsbruck Medical University, Innsbruck, Tyrol, Austria Department of Surgery, University of Pittsburgh, Pittsburgh, PA, USA Center for Inflammation and Regenerative Modeling, McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA Department of Plastic and Reconstructive Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA Objectives: Skin and muscle wounds often lead to significant inflammation in the affected tissue. The primary mechanism by which inflammation is initiated, sustained, and terminated is cytokine-mediated immune signaling, but this can be altered by cardiogenic shock. The complexity and context sensitivity of immune signaling in general stymied a clear understanding of these signaling dynamics. We hypothesized that advanced numerical and biological function analysis methods would help elucidate the inflammatory response to skin and muscle wounds in rats, both with and without concomitant shock. Methods: We studied 2 experimental groups: wound only (“wound group”) and wound with cardiogenic shock (“shock group”). In the “wound group,” 4 Lewis rats were anesthetized and an excision biopsy was taken from the lateral aspect of the thigh on one of the hind limbs in each of the rats. In the “shock group,” 4 Lewis rats were sacrificed, and excision biopsy (wound) was carried out 15 to 30 seconds after cessation of heartbeat. Skin and muscle tissue was then separated and assayed for total protein content by BCA assay, and the inflammation biomarkers interferon-γ, interleukin (IL)-1α, IL-1β, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12p70, IL-18, monocyte chemotactic protein (MCP-1), growth-related oncogene/KC, tumor necrosis factor α, and granulocyte-macrophage colony-stimulating factor were assayed by Luminex (Luminex Corp, Austin, TX). Caspase-1, which drives activation of the NLRP-3 inflammasome, was assessed by Western blot assay. Statistical and computational analyses of cytokine network profiles (1-way balanced analysis of variance, unpaired 1-tailed heteroscedastic t test, principal components analysis, and confirmatory factor analysis) were performed in Matlab (The MathWorks, Inc, Natick, MA). Results: Granulocyte-macrophage colony-stimulating factor was elevated in the wound group (P b .05), whereas IL-4, IL-12p70, interferon-γ, and IL-18 were elevated in the shock group (P b .05). Interleukin-1α and IL-18 were more elevated in skin vs muscle (P b .05), which was suggestive of inflammasome activation in the skin. MCP-1, IL-1β, IL-2, IL-6, IL-10, IL-4, IL-12p70, and tumor necrosis factor α (P b .05) were also differentially higher in skin vs muscle. Immunoblotting revealed caspase-1 activation in skin but not muscle. Notably, IL-1α and IL-18, along with caspase-1, were greatly elevated in the skin after cardiogenic shock (P b .05). Principal components analysis suggested that more than 95% of observed variance could be explained by 2 principal components in the skin and muscle and suggested distinct groups of inflammatory mediators induced in the “wound group” vs the “shock group”. Interleukin-18 and IL-1α were primary contributors to the first principal component, whereas IL-6, MCP-1, growth-related oncogene/KC, and IL-1β were primary contributors to the second principal component. Principal components analysis results were reinforced by confirmatory factor analysis. Conclusions: Caspase-1 and the NLRP-3 inflammasome appear to be key factors in determining the type and severity of the inflammatory response to excisional wounding, especially in the presence of shock. Activated caspase-1 is associated with defined, compartmentalized patterns of cytokine production that may be discerned via data-driven modeling. http://dx.doi.org/10.1016/j.jcrc.2012.10.038

Effect of Fibrin-binding Synthetic Oligopeptide on the Healing of Full-thickness Skin Wounds in Streptozotocin-induced Diabetic Rats

The aim of this study was to investigate whether topical application of fibrin-binding oligopeptides derived from FN promotes wound healing in streptozotocin (STZ)-induced diabetic rats. Oligopeptides including fibrin-binding sequences (FF3: CFDKYTGNTYRV, FF5 : CTSRNRCNDQ) of FN repeats were synthesized. Each peptide was loaded in 15 x 15 mm fibrous alginate dressings, and the release kinetics of the peptides was evaluated using trinitrobenzene sulfonic acid for 336 hours. Two full-thickness cutaneous wounds were prepared on the dorsal skin of each 75 diabetes induced rats. Each wound was divided into FF3-loaded alginate dressing group, FF5-loaded alginate dressing group, alginate dressing group and negative control group. Animals were sacrificed at day 0,3,7 and 14. The wound closure rate, inflammation degree, expression of TGF-β1 and hydroxyproline contents were evaluated. Both FF3 and FF5 peptides were released rapidly within the first 24 hours. FF3-loaded dressing treated wounds closed significantly faster than other wounds at day 3. And at day 14, FF3- & FF5- loaded dressing treated wounds demonstrated less inflammatory cells infiltration than alginate dressing treated and negative group wounds. TGF-β1 positive cells were more abundant in FF3-, FF5-treated alginate dressing treated wound at day 3 and 14. At last, the hyrdroxyproline contents in the FF3, FF5 group were higher at day 7 and day 14. Topical application of fibrin-binding domain synthetic oligopeptides from FN resulted in acceleration of full-thickness cutaneous wound healing in diabetic rats.

Effect of tissue-engineered chitosan-poly(vinyl alcohol) nanofibrous scaffolds on healing of burn wounds of rat skin

Chitosan-poly(vinyl alcohol) (Cs:PVA) nanofibrous scaffolds were electrospun from 2:3 (wt/wt) Cs:PVA solution dissolved in 80% acetic acid. In vivo study was carried out on the dorsum skin of rat which burnt with a hot brass cylinder. The scaffolds were applied in two forms, that is, acellular (n=6) and cell-seeded with mesenchymal stem cells (n=6). Macroscopic measurements of wound area showed good aspect healing effect of scaffolds in comparison with control wounds specially in 15 days post operating. Pathological studies were done on the wounds to investigate the healing effects. The healing process of the wound covered with Cs/PVA nanofibrous scaffolds was much rapid compared to untreated wounds. However, the presence of stem cells on this scaffolds accelerated the wound healing process owing to their ability of collagen regeneration.

Comparative effect of human andTrypanosoma cruzicalreticulin in wound healing

In orthopaedics, the use of factors that enhance granulation tissue formation and prevent or delay new bone regeneration is sometimes desirable. Calreticulin (CRT), a unique endoplasmic reticulum luminal Ca(2+) -binding chaperone widely distributed in eukaryotic cells, is involved in many cellular functions. Among them, CRT has an important influence in cutaneous wound healing and diverse processes associated with cutaneous repair, inhibition of angiogenesis, promotion of cell adhesion and antitumour effect. One of the molecules involved in several aspects of the host-parasite interplay is Trypanosoma cruzi calreticulin (TcCRT), which is highly homologous to human calreticulin (HuCRT). Here, recombinant (r)HuCRT and rTcCRT are compared on their abilities to affect fibroblast behaviour in a scratch plate assay, and wound healing in in vivo skin rat models. In molar terms, rTcCRT is three orders of magnitude more efficient than rHuCRT in increasing proliferation and migration of human fibroblasts in vitro. A similar effect was observed in vivo on rat skin wounds and inhibition of bone gap bridging in rabbit unicortical bone osteotomies.

An in vitro assessment of growth promoting activity of a synthetic basic fibroblast growth factor (b-FGF) using Rama-27 cell line

Growth factors (GFs) are naturally occurring proteins or steroid hormones which act as signaling molecules between cells that play a key role in the processes of proliferation, cell differentiation and maturation of a wide variety of cells and tissues. A recently purified synthetic basic b-FGF was assessed using a routine tissue culture assay via application of a wide range of doses ranged between 0.1 and 300ng/mL of the basic fibroblast growth factor (b-FGF) in phosphate buffer saline (PBS) and 10% fetal calf serum (FCS) on the growth rate of Rama-27 mammary cell line. Applying SPSS “Student T-test” biostatistics the result showed significant increase (p≤0.05), almost 7 folds in tissue proliferation at a low dose of 0.3ng/mL FGF in comparison with control tissue (PBS) only. It is concluded that 0.3ng/mL dose represents the lower optimal dose suggesting its possibility of an in vivo technique to test its potency in curing skin wounds in rats.

Electric fields guide migration of epidermal stem cells and promote skin wound healing

Migration of epidermal stem cells (EpSCs) into wounds may play an important role in wound healing. Endogenous electric fields (EFs) arise naturally at wounds. Consistent with previous reports, we measured outward electric currents at rat skin wounds using vibrating probes. Topical use of prostaglandin E2 significantly promoted wound healing. However, it is not known whether EpSCs respond to EFs. We first isolated and characterized EpSCs from rat skin. We then demonstrated that EpSCs isolated from the epidermis migrated directionally toward the cathode in EFs of 50-400 mV/mm. The directedness values increased in a dose- and time-dependent fashion. The migration speed of EpSCs was significantly increased in EFs. EFs induced asymmetric polymerization of intracellular F-actin and activation of the extracellular signal-regulated kinase 1/2 and phosphatidylinositol-3-kinase (PI3K)/protein kinase B pathways. Inhibition of epidermal growth factor receptor, extracellular signal-regulated kinase 1/2, or PI3K significantly inhibited the cathodal distribution of F-actin and the electrotactic response of EpSCs. These data for the first time show that EpSCs possess obvious electrotaxis, in which the epidermal growth factor receptor-mitogen activated protein kinase-PI3K pathways are involved. These data thus suggest a novel aspect of electric signaling in wound healing-to stimulate and guide migration of EpSCs and to regulate wound healing.

Effects of angico extract (Anadenanthera colubrina var. cebil) in cutaneous wound healing in rats

To study the effects of the angico extract (Anadenanthera colubrina var. cebil) on the healing of rat skin. Twenty adult rats were divided into four groups of five animals each, the G4, G7, G14 and G21, which corresponds to the respective postoperative days. Each group received two incisions on skin and subcutaneous tissue in the right and left antimere of the thoracic region, separated by a distance of 2 cm. The right lesion was treated daily with saline and the left with the angico alcoholic extract (5%). At the end of each experimental period, animals were euthanized and fragments of the wound area, together with the edges were removed, fixed in 10% formaldehyde solution and processed for paraffin embedding. In the histological sections with 5 µm of thickness, were carried out immunohistochemical methods for detection of blood vessels (VEGF) and stained with hematoxylin and eosin for morphological analysis. Statistical analysis was done by ANOVA and Tukey test (p<0.05). Morphological analysis showed larger fibroblasts and a higher concentration of collagen fibers in days 7 and 14 in wounds treated with the angico extract. Morphometric analysis demonstrated a significant increase in the number of blood vessels in both the seventh and 14th days (p<0.01) in wounds treated with the angico extract. The angico alcoholic extract (Anadenanthera colubrina var. cebil) induces the acceleration of wound healing in skin wounds of rats.

Silibinin Regulates Matrix Metalloproteinase 3 (Stromelysine1) Gene Expression, Hexoseamines and Collagen Production During Rat Skin Wound Healing

Silibinin (SB), a flavonoid isolated from the milk thistle, Silybum marianum, has been shown to exhibit protective effects against skin damage. The objective of the present study was to investigate the effect of topical application of SB on levels of stromelysine 1 (STM1) gene expression, acetyl hexoseamines and collagen production during skin wound healing. Full-thickness skin wounds were topically treated with 10% and 20% SB extract in acetonitril:olive oil (AOO) (4:1) for 30 days, and expression level of STM1 transcript, n-acetyl glucoseamine (NAGLA), n-acetyl galactoseamine (NAGAA) and collagen contents were analyzed on the 10th, 20th and 30th days post wounding. SB in dose- and time-dependent manner accelerated wound closure time and increased levels of STM1 mRNA, hydroxyproline, NAGLA and NAGAA compared to the untreated and vehicle (AOO)-treated rats. The current study provides evidence that SB, by increasing STM1 gene expression and extracellular matrix constituents including glycosaminoglycans and collagen contents, promotes a faster wound healing process and can be used as a healing agent in future.

Electrospun drug-eluting sutures for local anesthesia

We have developed a local anesthetic-eluting suture system which would combine the function and ubiquity of the suture for surgical repair with the controlled release properties of a biodegradable polymeric matrix. Drug-free and drug-loaded poly(lactic-co-glycolic acid) (PLGA) sutures were fabricated by electrospinning, with or without the local anesthetic bupivacaine. The tensile strength of the electrospun sutures decreased as drug content increased, but strains remained relatively similar across all groups. Sutures released their entire drug payload over the course of 12days and maintained approximately 12% of their initial tensile strength after 14days of incubation in vitro. In a rat skin wound model, local analgesia was achieved 1day after surgery and lasted approximately 1week in 90% of treated animals (n=10, p<0.05), and all wounds were able to heal normally without the need for further reinforcement. The sutures caused tissue reaction in vivo that was comparable to that seen with a commercially available suture composed of PLGA. Such sutures may enhance perioperative analgesia and mitigate the need for standard postoperative opioid analgesics.

Immunohistological changes in skin wounds during the early periods of healing in a rat model

The complexity of the wound healing process, which is still poorly understood, prompted us to perform an immunohistochemical investigation using rat skin as an in vivo model. Fifteen Sprague-Dawley rats were included in the experiment. Two round full thickness wounds, 4 mm in diameter, were made on the backs of all rats. Haematoxylin and eosin basic staining as well as antibodies against wide spectrum keratin, keratin 10, keratin&amp;nbsp;14, &amp;alpha;-smooth muscle actin, vimentin, fibronectin, collagens Type 1 and 3, and the transcription factor Sox-2 were applied to paraffin and frozen sections of skin wound specimens two, six and fourteen days after surgery, respectively. New hair follicles with Sox-2-positive cells were present after fourteen days; keratin/vimentin positivity was restricted to specimens of day two. Collagen-3 expression prevailed over collagen-1 expression at all evaluated time intervals, except in the uninjured part of the dermis. In conclusion, rat skin wound healing is a dynamic process which can serve as a model for studying phenomena such as cell-cell interactions and transitions in vivo.

Time-dependent effects of low-level laser therapy on the morphology and oxidative response in the skin wound healing in rats

This study aims to investigate the effect of different energy densities provided by low-level laser therapy (LLLT) on the morphology of scar tissue and the oxidative response in the healing of secondary intention skin wounds in rats. Twenty-four male adult Wistar rats were used. Skin wounds were made on the backs of the animals, which were randomized into three groups of eight animals each as follows, 0.9% saline (control); laser GaAsAl 30J/cm(2) (L30); laser GaAsAl 90J/cm(2) (L90). The experiment lasted 21days. Every 7days, the wound contraction index (WCI) was calculated and tissue from different wounds was removed to assess the proportion of cells and blood vessels, collagen maturation index (CMI), thiobarbituric acid reactive substance (TBARS) levels and catalase activity (CAT). On the 7th and 14th days, the WCI and the proportion of cells were significantly higher in groups L30 and L90 compared to the control (p < 0.05). At all the time points analyzed, there was a greater proportion of blood vessels and a higher CMI in group L90 compared to the other groups (p < 0.05). On the 7th and 14th days, lower TBARS levels and increased CAT activity were found in the L90 group compared to the control (p < 0.05). On the 7th day, a moderately negative correlation was found between TBARS levels and WCI, CMI and CAT in all the groups. LLLT may modulate the oxidative status of wounded tissue, constituting a possible mechanism through which the LLLT exerts its effects in the initial phases of tissue repair.

Effects of borage extract in rat skin wound healing model, histopathological study

Nowadays, borage flowers and leaves are used medicinally for wound healing because of plant constituents, gamma-linolenic acid, alpha linolenic acid and delta-6-fatty acid. The aim of of the present study was to evaluate the ability of borage extract ointment wound healing process. Under surgical anaesthesia, excisional wounds were made on back of 30 rats by punching. Rats were divided into 3 groups of borage 1.5% ointment, eucerin-vaseline, and control. All the rats were treated with topical ointments daily for 21 days. Histopathological examination was performed on the 3rd, 7th, 14th, and 21st days and the wound healing was assessed. The results showed that wound size of the test groups were reduced early as compared to control group. The significant results of histopathological evaluation were obtained with borage, when compared to the other groups as well as to the control and the placebo. Present study demonstrated that borage extract was capable of promoting wound healing process. Key words: Borage, herbal extract, histopathological study, rat, wound healing.

Topical treatment of oral cavity and wounded skin with a new disinfection system utilizing photolysis of hydrogen peroxide in rats

The present study aimed to evaluate the acute locally injurious property of hydroxyl radical generation system by photolysis of H(2)O(2), which is a new disinfection system for the treatment of periodontitis developed in our laboratory. Firstly, generation of the hydroxyl radical by a test device utilizing the photolysis of H(2)O(2) was confirmed by applying an electron spin resonance (ESR)-spin trapping technique. Secondly, the bactericidal effect of the device was examined under a simulant condition in which Staphylococcus aureus suspended in 1 M H(2)O(2) was irradiated with laser light emitted from the test device, resulting in substantial reduction of the colony forming unit of the bacteria within a short time as 2 min. Finally, acute topical effect of the disinfection system on rat oral mucosa and wounded skin was evaluated by histological examination. No abnormal findings were observed in the buccal mucosal region treated three times with 1 M H(2)O(2) and irradiation. Similarly, no abnormal findings were observed during the healing of skin treated with 1 M H(2)O(2) and irradiation immediately after wounding. Since topical treatment with the novel disinfection technique utilizing the photolysis of H(2)O(2) had no detrimental effect on the oral mucosa and the healing of full thickness skin wounds in rats, it is expected that the acute locally injurious property of the disinfection technique is low.

Upregulation of Ski in Fibroblast is Implicated in the Peroxisome Proliferator- Activated Receptor δ-Mediated Wound Healing

Background/Aim: Both peroxisome proliferator-activated receptor (PPAR) δ and Ski are investigate the interaction of PPARδ and Ski and this interaction-associated effect in wound healing. Methods: Effect of PPARδ activation on Ski expression was detected in rat skin fibroblasts by real-time PCR and western blot. Luciferase assay, electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) assay were performed to identify the binding site of PPARδ in the promoter region of rat Ski gene. And the functional activity of PPARδ regulation to Ski was detected in fibroblast proliferation and rat skin wound healing model. Results: PPARδ agonist GW501516 upregulated Ski expression in a dose-dependent manner. Direct repeat-1 (DR1) response element locating at -865∼-853 in Ski promoter region was identified to mediate PPARδ binding to Ski and associated induction of Ski. Furthermore, PPARδ upregulated Ski to promote fibroblasts proliferation and rat skin wound repair, which could be largely blocked by pre-treated with Ski RNA interference. Conclusion: This study demonstrates that Ski is a novel target gene for PPARδ and upregulation of Ski to promote fibroblast proliferation is implicated in the PPARδ-mediated wound healing.