Healing Of Experimental Skin Wounds Research Articles

Clock gene Per2 modulates epidermal tissue repair in vivo.

Wound healing can be influenced by genes that control the circadian cycle, including Per2and BMAL1, which coordinate the functions of several organs, including the skin. The aim of the study was to evaluate the role of PER2 during experimental skin wound healing. Two groups (control and Per2-KO), consisting of 14 male mice each, were anesthetized by inhalation, and two 6 mm wounds were created on their dorsal skin using a punch biopsy. A silicone ring was sutured around the wound perimeter to restrict contraction. The wound healing process was clinically measured daily (closure index) until complete wound repair. On Day 6, histomorphometric analysis was performed using the length and thickness of the epithelial migration tongue, in addition to counting vessels underlying the lesion by immunofluorescence assay and maturation of collagen fibers through picrosirius staining. Bromodeoxyuridine(BrdU) incorporation and quantification were performed using the subcutaneous injection technique 2 h before euthanasia and through immunohistochemical analysis of the proliferative index. In addition, the qualitative analysis of myofibroblasts and periostin distribution in connective tissue was performed by immunofluorescence. Statistically significant differences were observed in the healing time between the experimental groups (means: 15.5 days for control mice and 13.5 days for Per2-KO; p = 0.001). The accelerated healing observed in the Per2-KO group (p < 0.05) was accompanied by statistical differences in wound diameter and length of the migrating epithelial tongue (p = 0.01) compared to the control group. Regarding BrdU immunoreactivity, higher expression was observed in the intact epithelium of Per2-KO animals (p = 0.01), and this difference compared to control was also present, to a lesser extent, at the wound site (p = 0.03). Immunofluorescence in the connective tissue underlying the wound showed a higher angiogenic potential in the Per2-KO group in the intact tissue area and the wound region (p < 0.01), where increased expression of myofibroblasts was also observed. Qualitative analysis revealed the distribution of periostin protein and collagen fibers in the connective tissue underlying the wound, with greater organization and maturation during the analyzed period. Our research showed that the absence of the Per2 gene positively impacts the healing time of the skin in vivo.This acceleration depends on the increase of epithelial proliferative and angiogenic capacity of cells carrying the Per2 deletion.

Cold pressed Pinus halepensis Mill. seed oil for potential health applications: Analgesic, anti-inflammatory effects, and assessment of inflammatory mediators by RT-qPCR in skin wound healing

Ethnopharmacological relevancePinus halepensis Mill. seed (Pinaceae), commonly known as “Zgougou,” is widely consumed in the Mediterranean region and has long been used to treat diseases including bronchitis, rheumatism, infection, and inflammation. Aim of the studyThe present study was focused on the investigation of some pharmacological activities, such as analgesic, anti-inflammatory, and wound healing effects, of cold-pressed oil of Pinus halepensis Mill. seed (COPHS). Materials and methodsThe fixed oil of Pinus halepensis seed was extracted by a cold pressing process. The analgesic activity of COPHS was examined by acetic acid and formalin-induced contortion and pain tests. The anti-inflammatory effects were evaluated in carrageenan and formalin induced paw and ear edema models. Wound healing potential was assessed on an experimental skin wound, and the expression levels of inflammation mediators were determined by RT-qPCR in skin wound healing. ResultsThe results showed analgesic efficacy through significant inhibition of abdominal cramps (59.15%) and pain (75.91%). In addition, this oil exerted an anti-inflammatory effect by inhibiting ear (62.25%) and paw (70.00%) edema. The COPHS stimulated wound contraction in experimental skin wound healing with a contraction rate of 89.23% with notable reduction of TNF-α and NF-kB expression levels in the treated groups. ConclusionsThis study provided for the first time the pharmacological profile, particularly the analgesic, anti-inflammatory, and healing effects, of fixed oil extracted by cold pressing from the seed of Pinus halepensis Mill.

Effect of infrared and red monochromatic light on equine wound healing.

Light-emitting diodes (LEDs) are commonly used for treating a variety of disorders in horses, including wounds. Despite its claim to shorten healing times, there is a lack of scientific documentation regarding its effects. To investigate if treatment with pulsating visible red light (λ≈637nm) and near-infrared (NIR) light (λ≈956nm) affects wound healing. Randomised blinded controlled experimental study. A circular skin wound (Ø=2cm) was created on each side of the neck in eight healthy horses. One randomly chosen wound received light treatment and the other served as an untreated control. Treatment duration was 4minutes and 40seconds (red light 95seconds, 2.3mW/cm2 ; NIR light 185seconds, 6.4mW/cm2 ) and was performed once daily on day 0-4, 7-11, 14-18 and 21-25. The wounds were photographed and evaluated using digital photoplanimetry on day 0, 1, 2, 3, 4, 7, 14, 21, 28 and 35. The degree of swelling was assessed with diagnostic ultrasound on the same days except the last recording was performed on day 36 instead of 35. Days to total healing was recorded. ANOVA was used for statistical analysis (P<.05). The wound area (P=.2-.9) and degree of swelling (P=.2-1.0) did not differ between treated and control groups on any day. There was a significant difference (P=.03) in healing time between control (49.0, 95% CI=35.4-62.6days) and treated wounds (51.8, 95% CI=38.7-64.8days). The wounds were treated until day 25 and this study does not investigate the effect of a longer treatment period than 25days. The results of this study do not indicate any clinically relevant positive effect of pulsating visible red light and NIR light on the healing of experimental skin wounds in horses, compared with no treatment.

Oxytocin effects on experimental skin wound healing.

Objective:Oxytocin (OXY) has significant effects on mammalian behavior. Next to its role in lactation and social interactions, it is described to support better wound healing as well. However, direct OXY effects on wound healing and the regeneration of the microvascular network are still not clarified. We therefore examined the effects of OXY and an OXY receptor antagonist [atosiban (ATO)] on skin wound healing, focusing on epithelialization and neovascularization.Methods:Skin wound healing has been assessed using intravital fluorescence microscopy in a model of full dermal thickness wounds in the dorsal skin fold chamber of hairless mice. Animals received repetitive low or high doses of OXY or ATO. Morphological and cellular characterization of skin tissue repair was performed by histology and in vitro cell assays.Results:The assessment of skin tissue repair using this therapy regimen showed that OXY and ATO had no major influence on epithelialization, neovascularization, wound cellularity, or inflammation. Moreover, OXY and ATO did neither stimulate nor deteriorate keratinocyte or fibroblast migration and proliferation.Conclusion:In summary, this study is the first to demonstrate that OXY application does not impair skin wound healing or cell behavior. However, until now, the used transmitter system seems not to be clarified in detail, and it might be proposed that it is associated with the stress response of the organism to various stimuli.

Влияние N-пальмитоилэтаноламина и N-стеароилэтаноламина в липосомальной форме на заживление экспериментальных ран кожи

Влияние N-пальмитоилэтаноламина и N-стеароилэтаноламина в липосомальной форме на заживление экспериментальных ран кожи

Quantificação de fenóis, flavonoides totais e atividades farmacológicas de geoprópolis de Plebeia aff. Flavocincta do Rio Grande do Norte

Resumo: Esse estudo objetivou avaliar a composição química e potencial terapêutico do extrato hidroalcóolico de geoprópolis produzidas por abelhas Plebeia aff. flavocincta no semiárido do Rio Grande do Norte. Oito amostras (A-H) foram submetidas a quantificação dos teores de fenóis e flavonoides totais e avaliação da atividade antioxidante através do método DPPH (2,2-difenil-1-picril-hidrazilo). Além disso, foram investigadas as atividades antibacteriana, através do método de difusão em ágar, e a cicatrizante, através da indução de feridas cirúrgicas experimentais em Rattus norvegicus Berkenhout, 1769, linhagem Wistar, tratados com creme à base de geoprópolis. Duas amostras (F e G) se destacaram por apresentar altos valores de fenóis e flavonoides totais. A capacidade antioxidante acima de 90% foi observada em cinco amostras. Os extratos foram considerados eficazes no que se refere a atividade antibacteriana, pois das oito amostras, cinco promoveram a formação de halos de inibição ≥9mm para todas as cepas testadas. Duas amostras (D e G) se destacaram em relação as demais por apresentar excelentes resultados, uma vez que, promoveram a formação de halos de inibição para as bactérias Staphylococcus epidermidis e Escherichia coli, superiores estatisticamente aos valores dos antibióticos controles, quando na concentração de 100%. As amostras A e G promoveram, respectivamente, a formação de halos de inibição, que não diferiram significativamente dos halos produzidos pelos antibióticos controles em todas as concentrações testadas para E. coli e Staphylococcus aureus. A análise do processo de cicatrização sob os pontos de vista clínico, macroscópico e histológico permitiu concluir, que o uso do creme à base de geoprópolis apresentou influência positiva na cicatrização de feridas cutâneas experimentais, por promover reação inflamatória menos intensa e fechamento mais rápido das feridas em relação ao grupo controle.

Geometric and Histopathologic Assessment of Lavender Extracts (Lavandula stoechas) on Healing of Experimental Skin Wounds and its Comparison with Zinc Oxide on Rats

Geometric and Histopathologic Assessment of Lavender Extracts (Lavandula stoechas) on Healing of Experimental Skin Wounds and its Comparison with Zinc Oxide on Rats

Effect of photosensitizers pheophorbide a and protoporphyrin IX on skin wound healing upon low-intensity laser irradiation

The effect of photosensitizer with subsequent He-Ne (632.8 nm; 3 mW/cm2) laser irradiation on experimental skin wound healing has been studied. Pheophorbide a and protoporphyrin IX were used as photosensitizers. It was found that application of the photosensitizer and subsequent laser irradiation, first, decreased the amount and the functional activity of leukocytes in the wound exudate and, second, inhibited the SOD activity as compared with that of the control group. Moreover, pheophorbide and protoporphyrin practically did not affect the total healing period but decreased the length of the inflammation stage. It was supposed that these effects are related to generation of reactive oxygen species during irradiation.

Study on the effect of Peganum harmala extract on experimental skin wound healing in rat: pathological and biomechanical findings

This study was designed to evaluate the role of Peganum harmala extract on experimental skin wound healing. The investigation was carried out on 30 male Sprague-Dawley rats in the same conditions. Two uniform 7-mm diameter skin defect were created on the back of each animal by skin punch (total of 60 wounds). The extract was then applied once daily on half of the wounds. The animals were sacrificed on day 10 for histopathologic and biomechanical examinations. P. harmala extract significantly increased the number of fibroblasts and capillary buds and also decreased the epithelial gap which showed the better healing in treatment group. On the other hand, the improvement of biomechanical indices in treatment group revealed a significant increase in tensile strength of the wounds. It can be concluded that P. harmala is an effective herbal remedy in wound healing

The effect of low-intensity laser irradiation in the blue, green, and red spectral ranges on healing of experimental skin wounds in rats

The effects of low-intensity laser irradiation in the red (632.8 nm), green (532 nm), and blue (441.2 nm) spectral ranges on wound healing has been studied in rats. The effect of the traditionally used red laser irradiation has been compared with the effect caused by laser irradiation in other spectral ranges, aiming to support the provisional hypothesis that a similar healing effect could be achieved at lower doses of wound irradiation by lasers emitting in the blue and green spectral ranges. The following parameters have been used to characterize healing of the experimental wounds: the functional activity of phagocytes in the wound exudate, which was determined from luminol-dependent chemiluminescence, the phagocyte number; the wound exudates’ antioxidant activity; and the rate of healing, which was determined as the change of the wound surface area. It was found that in all cases the laser irradiation accelerated the healing of wounds. Exposure to red laser irradiation at the dose of 1.5 J/cm2), and to blue or green laser irradiation at a dose of 0.75 J/cm2 shortened the time of the wound healing from 22 to 17 and 19 days, respectively. The functional activity of leukocytes in irradiated groups increased by day 5 after surgery, whereas in the control group it decreased. The superoxide dismutase activity increased in all experimental groups by day 5 after surgery. Laser irradiation in the red spectral range at a dose of 1.5 J/cm2 resulted in a larger increase in superoxide dismutase activity, as compared to that found after exposure to laser irradiation in the blue and green spectral ranges at a dose of 0.75 J/cm2.

Influence of laser photobiomodulation upon connective tissue remodeling during wound healing

The modulation of collagen fibers during experimental skin wound healing was studied in 112 Wistar rats submitted to laser photobiomodulation treatment. A standardized 8 mm-diameter wound was made on the dorsal skin of all animals. In half of them, 0.2 ml of a silica suspension was injected along the border of the wound in order to enhance collagen deposition and facilitate observation. The others received saline as vehicle. The treatment was carried out by means of laser rays from an aluminum–gallium arsenide diode semiconductor with 9 mW applied every other day (total dose = 4 J/cm 2) on the borders of the wound. Tissue sections obtained from four experimental groups representing sham-irradiated animals, laser, silica and the association of both, were studied after 3, 7, 10, 15, 20, 30 and 60 days from the laser application. The wounded skin area was surgically removed and submitted to histological, immunohistochemical, ultrastructural, and immunofluorescent studies. Besides the degree and arrangement of collagen fibers and of their isotypes, the degree of edema, the presence of several cell types especially pericytes and myofibroblasts, were described and measured. The observation of Sirius-red stained slides under polarized microscopy revealed to be of great help during the morphological analysis of the collagen tissue dynamic changes. It was demonstrated that laser application was responsible for edema regression and a diminution in the number of inflammatory cells ( p < 0.05). An evident increase in the number of actin-positive cells was observed in the laser-treated wounds. Collagen deposition was less than expected in silica-treated wounds, and laser treatment contributed to its better differentiation and modulation in all irradiated groups. Thus, laser photobiomodulation was able to induce several modifications during the cutaneous healing process, especially in favoring newly-formed collagen fibers to be better organized and compactedly disposed.

Effect of synthetic peptide thrombin receptor agonist encapsulated in microparticles based on lactic and glycolic acid copolymer on healing of experimental skin wounds in mice

PAR1 peptide thrombin receptor agonist (PAR1-AP) was encapsulated in microcorpuscles based on lactic and glycolic acid copolymer. The desorption profile of the preparation was studied in vitro and its wound-healing effects were studied on a model of cut skin wound in mice. The study showed that 90% PAR1-AP was desorbed over 6 h, but the peptide was detected in eluates from the microparticle surface after 23 h. The desorbed peptide retained its physiological activity and was capable of activating PAR1 receptors on human platelets. The study of the dynamics of experimental skin wound healing in mice showed lower number of macrophages in the wounds treated with PAR1-AP microparticles compared to the control (open wounds and wounds covered with microparticles) and higher number of fibroblasts on day 3 of tissue reparation. Hence, PAR1-AP desorbed from microparticles shortened the inflammation phase in the wound. On day 7 the best healing parameters were also observed in wounds treated with PAR1-AP microparticles, which attests to shortening of the proliferation phase and acceleration of wound healing.

The role of oxygen therapy in the healing of experimental skin wounds and colonic anastomosis.

A number of experimental studies have indicated that wound healing is adversely affected by hypoxia, and it has been suggested that healing can be improved by increasing inspired oxygen tensions. However, this hypothesis is based on observations on simulated wounds or tissue implants in experimental animals, and the clinical relevance of these observations is uncertain. The effects of oxygen therapy on the healing of skin wounds and colonic anastomoses were examined in rats. Sutured skin incisions and normal and ischaemic colonic anastomoses were studied in control animals breathing air and in test animals breathing 50 per cent oxygen. Wound healing was assessed by measurements of wound breaking strength, colonic bursting wall tension and wound collagen after 7 days' treatment with oxygen. There was no significant difference in the measurements in skin wounds or colonic anastomoses in test and control animals, and there was a similar incidence of anastomotic dehiscence in the ischaemic colon of test animals and controls. Oxygen therapy had no apparent effect on wound healing in this study, and it was concluded that further studies are required to determine whether or not there is a rational basis for the clinical use of oxygen therapy to help wound healing.

Effect of a cationic detergent on healing of experimental skin wounds closed by suture and non-suture technique

Effect of a cationic detergent on healing of experimental skin wounds closed by suture and non-suture technique

Studies on wound healing.

Factors affecting the rate of healing of experimental skin wounds in rats have been investigated. The effectiveness of healing was measured by determining the tensile strengths of the incised skin after various time intervals. When the skin histamine content was lowered by treatment with polymyxin B or with compound 48/80, retardation of the healing process was evident from the reduced tensile strengths. When the skin 5-hydroxytryptamine content was lowered by treatment with reserpine, retardation of healing was also found. Heparin increased the rate of healing and more rapid healing was obtained by giving histamine before each dose of heparin. On the other hand, some glucocorticoids markedly inhibited the healing process. Of the constituents of the tissue mast cells, heparin appears to be more important than histamine and 5-hydroxytryptamine in promoting the healing of experimental skin wounds in rats.