RESUMEN
Intensive insulin therapy during critical illness protects the endothelium and thereby prevents organ failure. This study tested the hypothesis that insulin directly affects the attenuation of burn injury-induced damage to pulmonary endothelial tight junction and investigated the underlying mechanisms. Sprague Dawley rats with severe burn injury were randomized to treatment with insulin dissolved in normal saline (maintenance of blood glucose at a level between 5.0 and 7.0 mmol/L) or normal saline alone (in vivo treatment). Pulmonary damage was evaluated. Rat pulmonary microvascular endothelial cells were treated with 20% burn serum or 20% burn serum + insulin (in vitro treatment). Selected cultures were pretreated with phosphatidylinositol 3-kinase/protein kinase B (AKT) inhibitor (LY294002). Permeability was assessed by migration of bovine serum albumin across cell monolayers. Cells were stained with rhodamine phalloidin and were examined. Cell extracts were obtained to assess zonula occludens-1, occludin, and phosphorylated AKT levels by immunoblotting. Treatment with insulin attenuated the pulmonary edema, hemorrhage, and inflammatory cell infiltration of rats with severe burn injury. Burn serum significantly enhanced monolayer permeability to albumin, whereas treatment with insulin (10(-7 ) mol/L) limited this effect. Meanwhile, insulin (10(-7 ) mol/L) reduced burn serum-induced F-actin stress fiber formation and decreased zonula occludens-1 expression. LY294002 decreased cytoplasmic AKT phosphorylation and inhibited the protection effects of insulin. Through the phosphatidylinositol 3-kinase/AKT pathway, insulin independent of glucose toxicity can attenuate increased pulmonary endothelial permeability induced by burn injury. The effect is attributed to the attenuation of the architectural disruption of protein components of the endothelial tight junction. This result is useful in inhibiting multiple organ failure after burn injury.
Asunto(s)
Actinas/metabolismo , Quemaduras/tratamiento farmacológico , Cromonas/farmacología , Endotelio Vascular/patología , Inhibidores Enzimáticos/farmacología , Insulina/farmacología , Morfolinas/farmacología , Proteína Oncogénica v-akt/metabolismo , Inhibidores de las Quinasa Fosfoinosítidos-3 , Mucosa Respiratoria/patología , Uniones Estrechas/patología , Cicatrización de Heridas , Proteína de la Zonula Occludens-1/metabolismo , Actinas/biosíntesis , Animales , Glucemia/metabolismo , Quemaduras/metabolismo , Quemaduras/patología , Quemaduras/fisiopatología , Permeabilidad de la Membrana Celular , Células Cultivadas , Células Endoteliales/metabolismo , Endotelio Vascular/efectos de los fármacos , Activación Enzimática , Hemorragia/prevención & control , Insuficiencia Multiorgánica/prevención & control , Proteína Oncogénica v-akt/antagonistas & inhibidores , Fosforilación , Edema Pulmonar/prevención & control , Ratas , Ratas Sprague-Dawley , Mucosa Respiratoria/efectos de los fármacos , Uniones Estrechas/efectos de los fármacos , Uniones Estrechas/metabolismo , Proteína de la Zonula Occludens-1/biosíntesisRESUMEN
OBJECTIVE: To observe the effects of Angelica dahurica extracts on the biological characteristics of human dermal fibroblasts in vitro and to preliminary explore its possible therapeutic mechanism for wound healing. METHODS: The optimal concentration of Angelica dahurica extracts was identified by analysing of proliferation activity of human normal fibroblasts (Fb) that treated with different concentration of Angelica dahurica extracts through thiazole blue (MTT) colorimetric assay. Cell cycle, collagen I and collagen III mRNA levels of the optimal Angelica dahurica extracts treated Fb were detected by flow cytometry (FCM) and real-time PCR techniques. RESULTS: At concentrations of 5 × 10(-4) to 5 × 10(-2) g/L, the Angelica dahurica extracts significantly enhanced the proliferation of Fb. The most significant concentration was 5 × 10(-3) g/L (t = 5.79, P < 0.01), at which an increased percentage of G1 to S and S to G2 phase cells (t = 11.2, 5.69, 2.44, P < 0.05) as well as an increased level of collagen I (1.61 ± 0.26 vs. 1.00 ± 0.16) and collagen III mRNA (3.36 ± 0.40 vs. 1.00 ± 0.14) were obtained compared to the control group (t = 6.69, 7.64, P < 0.01). CONCLUSIONS: Angelica dahurica extracts can notably promote the proliferation of Fb and accelerating the cell cycle of Fb as well as up-regulating the expression of collagen I and collagen III, which may enhance the process of wound healing.
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Angelica/química , Dermis/citología , Fibroblastos/efectos de los fármacos , Extractos Vegetales/farmacología , Ciclo Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Células Cultivadas , Colágeno/metabolismo , Fibroblastos/citología , Fibroblastos/metabolismo , HumanosRESUMEN
A keloid is a benign skin tumor formed by an overgrowth of granulation tissue in affected patients. Peroxisome proliferator-activated receptor-γ (PPAR-γ) agonists were reported to be able to regulate extracellular matrix production in human dermal fibroblasts. This study explored the underlying molecular mechanism of PPAR-γ agonist troglitazone treatment for fibroblasts obtained from keloid patients. The data revealed that troglitazone treatment of keloid fibroblasts (KFs) downregulated the expression of early growth response-1 (Egr1) and collagen-1 (Col1). Level of Egr1 were closely associated with KF-induced fibrosis. The miRNA profiling data revealed that miR-543 was transcriptionally activated after troglitazone treatment. Bioinformatic analysis and experimental data showed that miR-543 was able to target Egr1. ELISA data confirmed that Col1 protein in the supernatant were modulated by the feedback regulatory axis of PPAR-γ agonist-induced miR-543 to inhibit Egr1 expression, whereas PPAR-γ antagonist treatment abolished such effect on Col1 suppression in KFs. This study demonstrated that the PPAR-γ agonist-mediated miR-543 and Egr1 signaling plays an important role in the suppression of collagen synthesis in KFs. Future in vivo studies are needed to confirm these in vitro data.
RESUMEN
Keloid, a skin benign tumor, is characterized by overgrowth of fibroblasts and the excessive deposition of extracellular matrix in wounded skin. Peroxisome proliferator-activated receptor-γ (PPAR-γ) agonist was recently evaluated to inhibit fibrosis. This study explored the underlying mechanisms. Fibroblasts isolated from 25 keloid patients (KFs) and fibroblasts isolated from healthy controls (NSFBs) were also subjected to treatment with PPAR-γ agonist troglitazone and antagonist GW9662 or for transfection with miR-92 mimics or inhibitor, Axl siRNA, and miR-92b or Axl promoter constructs, as well as being subjected to qRT-PCR, ELISA, Western blot, protein array, luciferase, and ChIP assays. The data demonstrated that TGF-ß1 and Axl proteins were significantly elevated in samples from keloid patients, while troglitazone treatment significantly reduced levels of TGF-ß1 and Axl mRNA and proteins in KFs. Moreover, knockdown of Axl expression reduced expression of TGF-ß1 and its pathway genes (such as α-SMA and Snail). PPAR-γ regulation of Axl expression was through transcriptional activation of miR-92b. miR-92b expression downregulated Axl expression at both mRNA and protein levels, whereas GW9662 completely reversed the inhibitory effects of miR-92b mimics on Axl expression. Gene ontology analysis of miR-92b targeting genes showed that TGF-ß and Axl were both potential targets of miR-92b, as confirmed by luciferase assay. These findings demonstrated that PPAR-γ-induced miR-92b expression inhibited Axl expression and in turn reduced expression of TGF-ß1 and the downstream genes in KFs, suggesting that targeting of this novel gene pathway may be useful for therapeutic control of fibrosis or keloid.
RESUMEN
Recent microRNA expression profiling studies have documented an up-regulation of miR-146a in several angiogenesis models. However, the underlying molecular mechanism of miR-146a in the angiogenic activity of endothelial cells has not been clearly elucidated. The present study was aimed to evaluate whether miR-146a promotes angiogenesis in HUVECs by increasing FGFBP1 expression via directly targeting CREB3L1. miR-146a was over expressed in HUVECs via lentiviral-miR-146a. Expression profiling analysis found miR-146a over expression resulted in up-regulation of angiogenesis and cytokine activity associated genes including FGF2. Further a combination of bioinformatics and experimental analyses demonstrated the CREB3L1 as a bona fide functional target of miR-146a during angiogenesis. Moreover, CREB3L1 inhibited luciferase expression from FGFBP1 promoter containing only CRE elements. Furthermore, CREB3L1 inhibited FGFBP1 expression by binding to two CRE-like sites located at approximately -1780-1777 and -868-865 bp relative to the FGFBP1 transcription start site. Additionally, ectopic expression of CREB3L1 decreased miR-146a-induced FGF2 secretion. These findings indicate that the miR-146a-CREB3L1-FGFBP1 signaling axis plays an important role in the regulation of angiogenesis in HUVECs and provides a potential therapeutic target for anti-angiogenic therapeutics.
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Proteínas Portadoras/metabolismo , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/metabolismo , Células Endoteliales de la Vena Umbilical Humana/fisiología , Péptidos y Proteínas de Señalización Intercelular/metabolismo , MicroARNs/metabolismo , Neovascularización Fisiológica , Proteínas del Tejido Nervioso/metabolismo , Transducción de Señal , Regulación hacia Arriba , Citocinas/metabolismo , HumanosRESUMEN
OBJECTIVE: The aim of the present study is to compare the effects of two alpha1-adrenoceptor antagonist terazosin and alfuzosin together with one alpha-adrenoceptor antagonist phenoxybenzamine on androgen-independent prostate cancer cell lines PC-3 and DU145. METHODS: Two androgen- independent cell lines, PC-3 and DU145, were used to determine the cell viability, colony-forming ability as well as cell cycle characteristics after exposure to these three drugs. RESULTS: This study showed that terazosin inhibited not only prostate cancer cell growth but also colony-forming ability, which is the main target of clinical treatment. On the other hand, alfuzosin and phenoxybenzamine have no effect on cell viability and colony forming ability of PC-3 and DU145. In addition, the terazosin inhibits cell growth through G(1) phase cell cycle arrest. CONCLUSION: This study provided the evidence that alpha1-adrenoceptor antagonist terazosin may have a therapeutic potential in the treatment of advanced androgen-independent prostate cancer.
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Antagonistas Adrenérgicos alfa/farmacología , Antineoplásicos/farmacología , Prazosina/análogos & derivados , Neoplasias de la Próstata/patología , Ciclo Celular/efectos de los fármacos , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Humanos , Masculino , Fenoxibenzamina/farmacología , Prazosina/administración & dosificación , Prazosina/farmacología , Quinazolinas/farmacologíaRESUMEN
OBJECTIVE: To reproduce a stable mouse model of deep partial-thickness scald and to determine the hypoxia status in the wound. METHODS: (1) A homemade scald-producing apparatus with constant steam (92 °C) emission was used to reproduce scald injury on the back (2 cm in diameter) in 80 male BALB/c mice for different duration (2, 4, 6, and 8 s), with 20 mice for each scald duration. The nozzle was aligned perpendicularly to the back of mice, 2 cm above the skin surface. The gross condition of wound was observed with naked eyes immediately after injury. Skin samples of 5 mice with different burn duration were harvested 0, 12, 24, and 48 h after scald for histopathological observation with hematoxylin and eosin staining, to screen the scalding time and time for biopsy of scalded skin to determine proper scalding time for the experiment. (2) Model of deep partial-thickness scald was reproduced with the desired scalding time as shown in the preliminary experiment in another 5 BALB/c mice. The hypoxia status in subcutaneous tissue was observed with immunohistochemical staining 72 h after scald. Another 20 BALB/c mice were divided into normal control group (n = 5, without scald) and deep partial-thickness scald group (n = 15, scalded for a suitable duration as determined in the preliminary experiment) according to the random number table. The subcutaneous oxygen content in wound center, the margin of the wound, and the normal skin adjacent to the wound was detected with laser Doppler transcutaneous oxygen tension 72 h after scald, with 5 mice in each region. Data were processed with one-way analysis of variance. RESULTS: (1) The wound of mice with different scald durations was pale, clean, and no exudate was observed right after injury. (2) The burn depth developed gradually along with the scalding time and sample harvesting time, and it became stable 24 h after scalding. A deep partial-thickness injury was observed in the dermis of mice scalded for 4 s and harvested 24 h after scald, and it was shown that the external hair sheath was still present, and it was determined to be a deep partial-thickness scald. (3) Dense staining of pimonidazole (hypoxia) was found in deep partial-thickness scald wound 72 h after scald, especially in the marginal zones of the wounds. The partial oxygen pressure in the wound center, wound margin, and normal skin around the wound was respectively (36.2 ± 3.2), (37.0 ± 1.4), (37.4 ± 2.7) mm Hg (1 mm Hg = 0.133 kPa), showing no statistically significant difference among them (F = 74.705, P > 0.05), but they were significantly lower than that of the control group [(53.1 ± 2.4) mm Hg, with F values respectively 82.377, 91.375, 100.531, P values all below 0.05]. CONCLUSIONS: Deep partial-thickness scald model can be reproduced in (20.0 ± 1.0) g male BALB/c mice by scalding with 92 °C hot steam for 4 s, and the depth of wound becomes stable 24 h after scalding. Hypoxia can be found in the scalded wounds, especially in the marginal zones of the wounds.
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Quemaduras , Modelos Animales de Enfermedad , Hipoxia/etiología , Animales , Quemaduras/complicaciones , Quemaduras/metabolismo , Quemaduras/patología , Hipoxia/metabolismo , Hipoxia/patología , Masculino , Ratones , Ratones Endogámicos BALB CRESUMEN
Skin is the largest organ in human body. It guards the underlying muscles, bones, ligaments, and internal organs. The skin faces the environment, and it is the first line to defend against the assaults of external physical, chemical, and micro-organic factors. The other functions of skin include systemic metabolism, temperature regulation, sensation, and production of vitamin D and folate. Skin injury usually leads to barrier function damage. Extensive skin injury would induce a series of problems such as water-electrolyte disorder, hypoproteinemia, and severe infection. Thus it is important to choose a suitable wound dressing when the skin is severely injured. The characteristics of wound dressings have undergone repeated and noticeable changes over the last several years. Compared with that of the traditional dressing, the ability of new dressings is improved obviously in the properties of wound protection, infection prevention, and wound healing promotion. This article deals with an overview on the characteristics of different wound dressings.
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Vendajes , Quemaduras/cirugía , Piel Artificial , Cicatrización de Heridas , Humanos , Piel/lesionesRESUMEN
OBJECTIVE: To study the role of Wnt/beta-catenin signaling in the phenotype change of normal skin fibroblasts (NFb) into myofibroblasts and the underlying mechanism. METHODS: NFb were isolated by collagenase digestion and cultured. (1) Experiment one. NFb were divided into four groups according to the random number table. Cells in control group were cultured with serum-free DMEM nutrient solution (briefly called nutrient solution). Cells in TGF-beta1 group were cultured with nutrient solution containing 10 ng/mL recombinant human TGF-beta1 (the same concentration for following experiments). Cells in Wnt3a group were cultured with nutrient solution containing 150 ng/mL Wnt3a (the same concentration for following experiments). Cells in TGF-beta1 + Wnt3a group were cultured with nutrient solution containing TGF-beta1 and Wnt3a. The mRNA and protein expression levels of beta-catenin and alpha-smooth muscle actin (alpha-SMA) were determined by real-time fluorescent quantitative PCR and Western blotting at post culture hour (PCH) 48. (2) Experiment two. NFb were divided into four groups according to the random number table. Cells in control group and TGF-beta1 group were treated as those in the corresponding groups in experiment one. Cells in SB415286 (glycogen synthase kinase-3beta inhibitor) group were cultured with nutrient solution containing 10 micromol/L SB415286 (the same concentration for following experiments). Cells in TGF-beta1 + SB415286 group were cultured with nutrient solution containing TGF-beta1 and SB415286. The mRNA and protein expression levels of alpha-SMA were determined by real-time fluorescent quantitative PCR and Western blotting, and the alpha-SMA-positive myofibroblasts were detected by immunofluorescence cytochemical staining at PCH 48. The experiments were all repeated for three times. Data were processed with analysis of variance and LSD- t test. RESULTS: (1) Experiment one. There was no statistically significant difference among four groups in beta-catenin mRNA level (F = 0.302, P = 0.823). There were statistically significant differences among four groups in beta-catenin protein level (F = 16.713, P = 0.001). The protein level of beta-catenin was higher in TGF-beta1 group (0.73 +/- 0.12) and Wnt3a group (0.82 +/- 0.17) than in control group (0.34 +/- 0.11, with t values respectively 3.028, 3.727, P < 0.05 or P < 0.01). The protein level of beta-catenin in TGF-beta1 + Wnt3a group (1.23 +/- 0.21) was higher than that of the other three groups (with t values respectively 6.911, 3.883, 3.184, P values all below 0.01). There were statistically significant differences among four groups in alpha-SMA mRNA level (F = 31.830, P = 0.001). Compared with that of control group, the expression level of alpha-SMA mRNA was up-regulated in TGF-beta1 group and down-regulated in Wnt3a group (with t values respectively 6.759, 2.535, P < 0.05 or P < 0.01). The expression level of alpha-SMA mRNA in TGF-beta1 + Wnt3a group was lower than that of TGF-beta1 group (t = 4.532, P < 0.01). The protein levels of alpha-SMA in control, TGF-beta1, Wnt3a, and TGF-beta1 + Wnt3a groups were respectively 0.83 +/- 0.17, 1.43 +/- 0.20, 0.53 +/- 0.12, and 0.89 +/- 0.14 (F = 16.597, P = 0.001). Compared with that of control group, the protein level of alpha-SMA was up-regulated in TGF-beta1 group and down-regulated in Wnt3a group (with t values respectively 4.582, 2.291, P < 0.05 or P < 0.01). The protein level of alpha-SMA in TGF-beta1 + Wnt3a group was lower than that of TGF-beta1 group (t = 4.123, P < 0.01). (2) Experiment two. There were statistically significant differences among four groups in alpha-SMA mRNA level (F = 34.101, P = 0.001). The alpha-SMA mRNA level in SB415286 group was lower than that of control group (t = 2.511, P < 0.05). The alpha-SMA mRNA level in TGF-beta1 + SB415286 group was lower than that of TGF-beta1 group (t = 3.587, P < 0.01). There were statistically significant differences among four groups in alpha-SMA protein level (F = 11.381, P = 0.003). The alpha-SMA protein level was lower in SB415286 group than in control group (t = 2.364, P < 0.05). The alpha-SMA protein level was down-regulated in SB415286 +TGF-beta1 group as compared with that of TGF-beta1 group (t = 2.556, P < 0.05). There were few alpha-SMA-positive fibroblasts in control group. Compared with that of control group, the expression of alpha-SMA was significantly increased in TGF-beta1 group (t =11.198, P < 0.01), and the expression of alpha-SMA was down-regulated in SB415286 group. Meanwhile, the expression of alpha-SMA in TGF-beta1 + SB415286 group were significantly lower than that of TGF-beta1 group (t = 5.902, P < 0.01). CONCLUSIONS: The Wnt/beta-catenin signaling might be involved in the fibroblasts-myofibroblasts transition, and it negatively regulate the TGF-beta1 -mediated profibrotic effects.
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Fibroblastos/metabolismo , Vía de Señalización Wnt , beta Catenina/metabolismo , Células Cultivadas , Fibroblastos/citología , Humanos , Fenotipo , Factor de Crecimiento Transformador beta1/metabolismoRESUMEN
Thermal injury inhibits Akt activation and upregulates p38 mitogen-activated protein kinase, which in turn induces inflammation and increases apoptosis. This study aimed to elucidate the mechanism underlying the cytoprotective role of insulin in severe burns by examining the effects of insulin on inflammation and apoptosis mediated by p38 mitogen-activated protein kinase in burn serum-challenged cardiomyocytes. Neonatal rat cardiomyocytes were exposed to burn serum for 6 hours in the presence or absence of insulin and pretreated with inhibitors to p38 mitogen-activated protein kinase (SB203580) and Akt (LY294002). The authors examined expression of myocardial tumor necrosis factor-alpha, cardiac myofilament proteins caspase-3 and Bcl2, and apoptosis. Burn serum-induced upregulation of tumor necrosis factor was inhibited by both SB203580 and insulin. LY294002 reversed insulin-mediated downregulation of tumor necrosis factor. Both SB203580 and insulin inhibited apoptosis, resulting in fewer pyknotic nuclei and inhibition of caspase-3 activation and Bcl2 downregulation. LY294002 reversed insulin-mediated inhibition of apoptosis. Insulin decreases inflammatory cytokine expression and apoptosis via PI3K/Akt-mediated inhibition of p38 mitogen-activated protein kinase. The cytoprotective role of insulin suggests that it may have a potential role in strategies for treating thermal injuries.
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Quemaduras/metabolismo , Insulina/farmacología , Miocitos Cardíacos/metabolismo , Proteínas Quinasas p38 Activadas por Mitógenos/antagonistas & inhibidores , Análisis de Varianza , Animales , Apoptosis , Quemaduras/complicaciones , Quemaduras/patología , Caspasa 3/biosíntesis , Inhibidores de Caspasas , Modelos Animales de Enfermedad , Expresión Génica , Inflamación/prevención & control , Ratas , Transducción de Señal , Factor de Necrosis Tumoral alfa/antagonistas & inhibidores , Factor de Necrosis Tumoral alfa/biosíntesis , Proteínas Quinasas p38 Activadas por Mitógenos/biosíntesisRESUMEN
OBJECTIVE: To observe the effect of vacuum sealing drainage (VSD) on the proliferation of Pseudomonas aeruginosa (PA) in infected wound, and to explore its possible mechanism. METHODS: Full-thickness skin wounds each with area of 1 cm x 1 cm were produced on the back of 40 C57 BL/6 mice, and then they were contaminated with wild type PA strains PAO1 marked with target gene of bacterial luciferase luxCDABE (PAO1-lux), they were dressed for 24 hours to reproduce PA infection model. Then mice were divided into experiment [E, with treatment of VSD (pressure value at -16.625 kPa)] and control (C, with treatment of conventional dressing change) groups according to the random number table, with 20 mice in each group. The fluorescence intensity of PAO1-lux and blood flow in wound was respectively measured by in vivo optical imaging system and laser Doppler perfusion imager before treatment and at post treatment hour (PTH) 24. The expression levels of IL-1beta and vascular endothelial growth factor (VEGF) mRNA in wound edge were determined by real-time fluorescence quantitative RT-PCR before treatment and at PTH 24. The specimens of wound edge tissue were collected for observation of pathological change at PTH 24. Data were processed with t test. RESULTS: There were no obvious difference in fluorescence intensity of PAO1-lux and blood flow in wound between E and C groups before treatment (with t value respectively 0.03, 0.50, P values all above 0.05). The fluorescence intensity of PAOl-lux and blood flow in wound in E group at PTH 24 [(2.69 +/- 0.75) photons x s(-1) x cm(-2) x sr(-1) and (96 +/- 9) PU] was respectively lower and higher than that inC group [(5.18 +/- 0.96) photons x s(-1) cm x (-2) x sr(-1) and (70 +/- 11) PU, with t value respectively 3.54, 3.13, P values all below 0.05]. The expression levels of IL-1beta and VEGF mRNA in both groups before treatment were similar (with t value respectively 0.19, 0.07, P values all above 0.05). The expression levels of IL-1beta and VEGF mRNA in E group at PTH 24 was respectively 4.72 +/- 0.37, 2.68 +/- 0.39, all markedly higher than those in C group (2.24 +/- 0.50, 1.22 +/- 0.13, with t value respectively 6.90, 6.12, P values all equal to 0.00). The number of inflammatory cell infiltrating the wound edge in E group at PTH 24 was increased by nearly 77% as compared with that in C group. CONCLUSIONS: Compared with conventional dressing change, VSD can reduce the amount of Pseudomonas aeruginosa in full-thickness skin defect wound at the early stage, it may be related with an increase in blood flow and number of inflammatory cells in wound tissue, promoting expression of IL-1beta and VEGF mRNA.
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Terapia de Presión Negativa para Heridas , Infecciones por Pseudomonas/terapia , Infección de Heridas/terapia , Animales , Modelos Animales de Enfermedad , Masculino , Ratones , Ratones Endogámicos C57BL , Pseudomonas aeruginosa , Cicatrización de HeridasRESUMEN
Nonmetabolic effects of intensive insulin therapy in critically ill patients have been reported, but the underlying mechanisms are unclear. This study was designed to test the hypothesis that intensive insulin treatment would attenuate burn-induced acute lung injury by protecting the pulmonary microvascular endothelium. The rat model of burn injury was achieved by exposure to 92°C water for 18 seconds. The rats were randomly allocated into the sham, burn/normal saline (NS), and burn/intensive insulin treatment groups. Blood glucose level was maintained between 5 and 7 mmol/L in rats in the burn/intensive insulin treatment group. Pulmonary injury was assessed by hematoxylin and eosin staining, scanning electron microscopy, bronchoalveolar lavage fluid protein concentrations, the lung wet:dry weight ratio, and lung myeloperoxidase activity. Pulmonary microvascular endothelial cells were examined by transmission electron microscopy. Western blotting was used to determine the protein expression of caspase-3. Intensive insulin treatment markedly attenuated the acute lung injury, revealed by improvements in histological features and significant decreases in bronchoalveolar lavage fluid protein concentrations, pulmonary wet:dry weight ratio, and myeloperoxidase activity at 12 hours after injury (P < .05 or P < .01 vs burn/NS). Moreover, the injured pulmonary microvascular endothelial cells showed significant improvements, whereas caspase-3 was markedly downregulated in the burn/intensive insulin treatment group when compared with the burn/NS group. Overall, intensive insulin treatment efficiently attenuated pulmonary microvascular endothelial cell dysfunction, decreased cell apoptosis, and inhibited acute lung injury after a burn. These findings may be useful in preventing organ failure after burn injury.
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Lesión Pulmonar Aguda/prevención & control , Quemaduras/complicaciones , Insulina/farmacología , Pulmón/efectos de los fármacos , Lesión Pulmonar Aguda/etiología , Lesión Pulmonar Aguda/patología , Análisis de Varianza , Animales , Glucemia/análisis , Western Blotting , Caspasa 3/metabolismo , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Esquema de Medicación , Endotelio/efectos de los fármacos , Endotelio/patología , Inmunohistoquímica , Inyecciones Subcutáneas , Pulmón/patología , Masculino , Peroxidasa/metabolismo , Distribución Aleatoria , Ratas , Ratas Sprague-Dawley , Valores de ReferenciaRESUMEN
OBJECTIVE: To investigate the possibility of crosstalk between phosphatidylinositol 3-kinase (PI3-K)/Akt pathway and p38 mitogen-activated protein kinase (p38MAPK) pathway in cardiomyocyte with challenge of burn serum, and to explore their influence on cardiomyocyte injury after burn. METHODS: The model of murine cardiomyocyte with stimulation of burn serum was established. (1) The level of Akt and p38 phosphorylation in cardiomyocyte were examined with stimulation of 10% burn serum before stimulation and 1, 3, 6, 12, 24 hour after stimulation. (2) The levels of Akt and p38 phosphorylation in cardiomyocyte were determined with stimulation of burn serum (at concentration of 5%, 10%, 20%) or 10% burn serum plus insulin (at concentration of 1 x 10(-8), 1 x 10(-7), 1 x 10(-6)mol/L). The content of creatine kinase (CK) in supernate was also detected. (3) Addition to the inhibitor of p38 MAPK pathway (SB203580) and PI3K/Akt pathway (LY294002), the level of p38MAPK, PI3K/Akt and the content of CK in supernate were determined. RESULTS: (1) The level of p-p38 in cardiomyocyte was 4.0 +/- 0.8, 3.6 +/- 0.8, 5.1 +/- 1.6, 2.4 +/- 0.5, 3.0 +/- 0.6 at 1, 3, 6, 12, 24 hour (s) after stimulation of burn serum, which was obviously higher than that immediate after stimulation (1.0, P < 0.01). The level of p-Akt was 0.15 +/- 0.07, 0.64 +/- 0.10, 0.26 +/- 0.08, 0.38 +/- 0.11, 0.59 +/- 0.13, which was obviously lower than that before stimulation (1.00, P < 0.01). (2) With stimulation of different concentration of burn serum or burn serum plus insulin, the level of p-Akt and p-p38 changed in the opposite directions comparatively. The content of CK increased along with increase of burn serum concentration, but decreased obviously with treatment of insulin (P < 0.05 or 0.01). (3) Low level of p38 induced by burn serum was increased after treatment of LY294002, which neutralized the protection of insulin (P < 0.01). Low level of p-Akt induced by burn serum increased after treatment of SB203580 (P < 0.01), which inhibited the release of CK induced by burn serum. CONCLUSION: There is being crosstalk between PI3K/Akt pathway and p38 MAPK pathway in cardiomyocytes with challenge of burn serum, which may regulate cardiomyocytes.
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Quemaduras/sangre , Miocitos Cardíacos/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Suero , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismo , Animales , Masculino , Ratas , Ratas Sprague-Dawley , Transducción de SeñalRESUMEN
OBJECTIVE: To investigate the protective effect of insulin on oxygen-radical induced hepatic injury in severely scalded rats in early stage of severe scald. METHODS: Eighty-four male Sprague-Dawley rats were randomly divided into three groups: i. e, normal group, saline group, and insulin group, with 28 rat in each group. The rats in the latter two groups were subjected to 30% TBSA full-thickness scald on the back, and received intra-peritoneal injection of 40ml/kg isotonic saline, and subcutaneous injection of 3 IU/kg insulin, respectively. The total anti-oxygen capability (T-AOC), the expression of superoxide dismutase (SOD), reactive oxygen species (ROS) and intercellular adhesion molecule (ICAM-1) in hepatic tissue, and serum alanine transaminase (ALT) were determined in each group at 6, 12, 24, 48 post-scald hours (PSH) with corresponding methods. RESULTS: The hepatic T-AOC and SOD content were obviously decreased, while the ROS content were markedly increased at 6 PSH in saline group compared with that in normal group (P < 0.05 or P < 0.01). The expression of ICAM-1 and serum content of ALT were significantly higher than that in normal group at 12 PSH and 48 PSH (P < 0.01). At 24 PSH, the hepatic T-AOC (386 +/- 75) U/g and SOD content (210 +/- 39 ) U/g were obviously higher in insulin group than those in saline group [(124 +/- 18), (111 +/- 9) U/g, respectively, P < 0.01), but the ROS content (154 +/- 29 ) U/g was much lower than that in saline group [(351 +/- 41) U/g, respectively, P < 0.01]. At 48 PSH, the serum content of ALT and hepatic expression of ICAM-1 in insulin group exhibited obvious difference when compared with those in saline group (P < 0.01). Meanwhile, Pathological examination showed that hepatic injury was alleviated by insulin administration after scald. CONCLUSION: Insulin administration early after severe scald exhibits protective effect on liver function by improving anti-oxygen radical ability of rat liver.
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Quemaduras/metabolismo , Insulina/farmacología , Hígado/efectos de los fármacos , Hígado/metabolismo , Alanina Transaminasa/sangre , Animales , Quemaduras/patología , Hígado/patología , Masculino , Distribución Aleatoria , Ratas , Ratas Sprague-Dawley , Especies Reactivas de Oxígeno/metabolismo , Superóxido Dismutasa/metabolismoRESUMEN
OBJECTIVE: To investigate the protective effect of insulin on vascular endothelial cells of rats at early post-burn stage,and its mechanism. METHODS: Adult male Sprague-Dawley rats were randomly divided into 3 groups: i. e, sham scald group (n = 7), scald group (n = 7) and treatment group (n = 7). The rats in the latter 2 groups were subjected to 30% TBSA full-thickness burns with 94 degrees C water, and the sham scald rats were treated with 37 degrees C water. Intra-peritoneal injection of 40 ml/kg isotonic saline solution and subcutaneous injection of 3 units/kg insulin were given to the rats in treatment group after being subjected to 30% TBSA full-thickness burns. Subcutaneous injection of equal amount of isotonic saline was given to the sham and burn groups. The changes in vascular endothelial cell structure were observed with electron microscopy at 24 post-scald hours(PSH). Meanwhile, the blood glucose contents, the serum levels of nitric oxide (NO) and nitric oxide synthetase (NOS) were determined with oxidase method and colorimetric method, respectively. RESULTS: The injury of arterial endothelial cells in the treatment group was obviously alleviated compared with that in burn group. The blood glucose content in the treatment group (7.1 +/- 0.7 mmol/L) was significantly lower than that in scald group (8.2 +/- 1.0 mmol/L, P < 0.05), though it was much higher in both groups than that in sham scald group (4.9 +/- 0.8 mmol/L, P < 0.01) at 24 PBH. The serum content of NO, total NOS and cNOS in treatment group were obviously higher than those in scald group (P < 0.01), but there was no obvious difference in iNOS content between the two groups(P > 0.05). CONCLUSION: Insulin exhibits protective effect on vascular endothelial cells in severely scalded rats at the early post-burn stage, and it is attributed to its promotion of cNOS level leading to NO production.
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Quemaduras/sangre , Quemaduras/tratamiento farmacológico , Células Endoteliales/efectos de los fármacos , Insulina/uso terapéutico , Animales , Glucemia/análisis , Quemaduras/patología , Modelos Animales de Enfermedad , Células Endoteliales/patología , Masculino , Óxido Nítrico/sangre , Óxido Nítrico Sintasa/sangre , Distribución Aleatoria , Ratas , Ratas Sprague-DawleyRESUMEN
OBJECTIVE: To study the protective effect of intensive insulin treatment on the myocardium of severely scalded rats, and to primarily explore its mechanism. METHODS: Eighteen SD rats were divided into three groups, with 6 rats in each group. The rats in burn and intensive insulin group were inflicted with 30% TBSA full-thickness injury on the back. Isotonic saline containing 0.12 U/ml insulin solution, and 100 g/L glucose solution were infused into the rats in the intensive insulin group to keep plasma glucose at the level of 4.0 - 6.6 mmol/L (the total fluid amount was 2 ml x kg(-1) x 8h(-1)). In sham burn group,fluid was given according to physiological demand. The same amount of isotonic saline was infused into the rats in burn group. The venous blood was obtained for the detection of plasma glucose contents, and the left ventricular systolic pressure (LVSP) and left ventricular end-diastolic pressure (LVEDP) were recorded via aortic ventricle cannula before scald and at 1, 2, 3, 4, 5, 6 post-scald hours (PSH). The tissue of the left ventricle was harvested at 6 PSH for the detection of troponin T expression in myocardiocytes. RESULTS: Plasma glucose level was increased to (7.6 +/- 1.7) mmol/L - (8.4 +/- 4.7) mmol/L in burn group during 1-6 PSH, which was significantly higher than that in intensive insulin group (4.5 +/- 0.9) mmol/L - (5.2 +/- 1.3) mmol/L, P < 0.01). Compared with the intensive insulin group, LVSP was markedly decreased in the burn group (60 +/- 11 mm Hg vs 72 +/- 8 mm Hg, P < 0.05) at 1 PSH,whereas LVEDP was increased significantly (21.3 +/- 11.3 mmHg vs 11.7 +/- 5.2 mmHg, P < 0.05). Intensive insulin treatment could significantly inhibit the loss of troponin T protein in myofilaments of myocardium. CONCLUSION: Intensive insulin treatment possesses a protective effect on myocardia function after severe burns, and it may be related to its preventive effect on the loss of contractile protein in cardiocytes.
Asunto(s)
Quemaduras/tratamiento farmacológico , Insulina/uso terapéutico , Miocardio/metabolismo , Animales , Glucemia/metabolismo , Quemaduras/metabolismo , Insulina/administración & dosificación , Masculino , Contracción Miocárdica , Ratas , Ratas Sprague-Dawley , Troponina T/metabolismoRESUMEN
OBJECTIVE: To investigate the current situation of animal experiments by analysis and evaluation of relevant articles published in the Chinese Journal of Burns during 2000 to 2004. METHODS: All articles concerning the results of animal experiments related to the treatment and medical studies in the past 5 years were analysed according to the international standard , especially in serval aspects, such as sample size, randomization method, sample choice, comparison measure, baseline comparability, estimate index, statistics method, and so oN. RESULTS: During 2000 to 2004, totally 1 116 papers were published in the journal, among them 81 papers were (accounted for 7.3% ) of all articles were reports of treatment related experiments. Out of 81 papers, in 69 experiments ( accounted for 85. 2% ) there was randomized control group, and the main problems lay in calculation of the number of samples, the application of randomization method, and analysis of statistics. CONCLUSION: Application of the randomized control modality in animal experiment is popular in our country, but the design of some studies is not so rigorous. Therefore, we should improve the design of every research project before the experiment is carried out.
Asunto(s)
Experimentación Animal/normas , Estudios de Evaluación como Asunto , Publicaciones Periódicas como Asunto/estadística & datos numéricos , Animales , QuemadurasRESUMEN
OBJECTIVE: To investigate the quality of reports of clinical results concerning burn injury, in order to raise the standard of clinical study of burn care in accordance to the standard of evidence-based medicine (EBM), with the aim of improving clinical research in burn care of this country. METHODS: All the papers of clinical study published in Chinese Journal of Burns (CJB) from 2000 to 2004 were evaluated according to EBM standard. RESULTS: There were 89 papers about clinical trials published in the past 5 years, in which 43 (48.3%) of the studies were carried out with random control trials (RCT), and 46 (51.7%) were clinical control trials (CCT). RCT papers increased year by year, while the number of CCT papers fluctuated greatly. The disparity in the quality of research was found as follows. In all the RCT and CCT papers, blinded research was adopted only in 5 papers (5.6%). Strict diagnostic standard including inclusion and exclusion standards were reported in 53 articles (59.6%). The comparison with baselines was not provided in 64 articles (71.9%). P value was given in 10 papers but statistical method was not mentioned (11.2%). Follow-up visits and lost information were only recorded in 2 articles, but no detailed follow-up visiting data were provided. Side effects were reported in 10 articles (11.2%). There were analysis and explanation of mixed interfering factors only in 5 papers (5.6%). There was no explanation of the evaluation of sample size in any one paper. CONCLUSION: In summary, the literature concerning clinical studies published in CJB in the past five years has become more extensive. However, the present study indicates that many clinical trials are not designed and ethical consideration is often missing. Therefore, it is deemed imperative to improve the quality of the clinical studies by improving the planning of the protocols of the study and statistical analysis of the research results in future.