Article

Molecular Mechanisms of Low Intensity Pulsed Ultrasound in Human Skin Fibroblasts

Department of Chemistry, Universität Ulm, Ulm, Baden-Württemberg, Germany
Journal of Biological Chemistry (Impact Factor: 4.57). 01/2005; 279(52):54463-9. DOI: 10.1074/jbc.M404786200
Source: PubMed

ABSTRACT

Soluble factors such as polypeptide growth factors, mitogenic lipids, inflammatory cytokines, and hormones are known regulators of cell proliferation. However, the effect of mechanical stimuli on cell proliferation is less well understood. Here we examined the effect of low intensity pulsed ultrasound (US), which is used to promote wound healing, on the proliferation of primary human foreskin fibroblasts and the underlying signaling mechanisms. We show that a single 6-11-min US stimulation increases bromodeoxyuridine incorporation. In addition, an increase in the total cell number is observed after sequential US stimulation. US induced stress fiber and focal adhesion formation via activation of Rho. We further observed that US selectively induced activation of extracellular signal-regulated kinase (ERK) 1/2. Inhibition of Rho-associated coiled-coil-containing protein kinase (ROCK) prevented US-induced ERK1/2 activation, demonstrating that the Rho/ROCK pathway is an upstream regulator of ERK activation in response to US. Consequently, activation of ROCK and MEK-1 was required for US-induced DNA synthesis. Finally, an integrin beta(1) blocking antibody as well as a RGD peptide prevented US-induced DNA synthesis. In addition, US slightly increased phosphorylation of Src at Tyr(416), and Src activity was found to be required for ERK1/2 activation in response to US. In conclusion, our data demonstrate for the first time that US promotes cell proliferation via activation of integrin receptors and a Rho/ROCK/Src/ERK signaling pathway.

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    • "ngiogenesis, increase in granulation tissue, increasing healing. (6,7,8) According to Johns (2002), determination of cell culture is described as a device that provides review and qualify several changes occurring in vitro and in vivo studies, and among the in vitro studies the effect of ultrasound results from the cell type and the parameter used. (5,9) Thus, Oliveira et al. (2009) to irradiate cultured fibroblasts, they found that the dosimetry, the system clock and control the intensity are crucial in improving the use of therapeutic ultrasound. In addition, low and medium intensity decrease cell damage, stating that the acoustic energy pulse induces the proliferation of fibroblast"
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    ABSTRACT: In vitro and in vivo put in evidence that the Low Intensity Pulsed Ultrasound therapy exerts a significant influence on cell function (cytoskeleton organization, stimulation of mitochondrial activity, ATP levels and plasma membrane). Objective: This study will analyze the radiation of low intensity pulsed ultrasound in fibroblast cells L 929. Method: In this study are presented the data from each exposure group average and standard deviation in each moment of evaluation (24 hours, 48 hours and 72 hours). The control group (received no radiation), 0.2 W/cm2 with 10% pulse regime (1: 9 duty cycle), 0.2 W / cm2 with 20% pulse regime (2: 8 cycle work), 0.4 W/cm2 with pulse scheme 10% (1: 9 duty cycle), 0.4 W/cm2 with pulse scheme 20% (2: 8 duty cycle). The analyzes will be performed through optical microscopy, MTT method 3 - (4,5-dimethylthiazol-2-yl) -2,5 diphenyl tetrazolium bromide, within the incubation times of 24, 48 and 72 hours. Results: Given the above study, the results presented in this project will be directed to increase the stimulation process and proliferation of fibroblast cells from the pulsed ultrasonic irradiation of low intensity, correlating with the healing process, neovascularization and repair. Conclusion: Therefore, the study of the effect of ultrasound from cell culture provides us with a simple and informative model on the significant aspects of the use of physical therapy in vivo system.
    Preview · Article · Nov 2015
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    • "However, only fragmented findings have so far been reported on this topic. A general trend that has been observed is post-exposure cytoskeletal remodeling (Hauser et al. 2009; Mizrahi et al. 2012; Noriega et al. 2013; Zhang et al. 2012), and it may result in the alteration of the cell's adherence characteristics (Mahoney et al. 2009; Roper et al. 2012; Zhou et al. 2004). In line with this trend, post-exposure bio-assays have revealed that a cell's mechanotransduction pathway would be activated by low-intensity ultrasound (Louw et al. 2013; Whitney et al. 2012), and in turn, its associated molecular signaling cascades would be modulated (Favaro-Pipi et al. 2010; Ito et al. 2012; Lu et al. 2009). "
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    ABSTRACT: To establish the therapeutic potential of low-intensity ultrasound, it is important to characterize its biophysical interactions with living cells. Here, through a series of single-cell direct observations, we show that low-intensity ultrasound pulsing would give rise to a dynamic course of cytomechanical perturbations at both the membrane and nucleus levels. Our investigation was conducted using a composite platform that coupled a 1-MHz ultrasound exposure hardware to a confocal microscopy system. Short ultrasound pulses (5 cycles, 2-kHz pulse repetition frequency) with a spatial-peak time-averaged intensity of 0.24 W/cm2 (0.85-MPa peak positive acoustic pressure) were delivered over a 10-min period to adherent Neuro-2a neuroblastoma cells, and live imaging of cellular dynamics was performed before, during and after the exposure period. Bright-field imaging results revealed progressive shrinkage of cellular cross-sectional area (25%–45%, N = 7) during low-intensity ultrasound pulsing; the initial rate of size decrease was estimated to be 8%–14% per minute. This shrinkage was found to be transient, as the sonicated cells had recovered (at a rate of size increase of 0.4%–0.9% per minute) to their pre-exposure size within 30 min after the end of exposure. Three-dimensional confocal imaging results further revealed that (i) ultrasound-induced membrane contraction was volumetric in nature (21%–45% reduction), and (ii) a concomitant decrease in nucleus volume was evident (12%–25% reduction). Together, these findings indicate that low-intensity ultrasound pulsing, if applied on the order of minutes, would reversibly perturb the physical and subcellular structures of living cells.
    Full-text · Article · Jul 2014 · Ultrasound in medicine & biology
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    • "This is the stage at which cells migrate to the site of injury and start to divide, granulation tissue is formed, and fibroblasts begin to produce collagen. Ultrasound has been shown to enhance collagen synthesis by fibroblasts and repairing of epithelium (Zhou et al., 2004). Many laboratory-based studies have been undertaken to understand the effects of ultrasound on wound healing. "
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    ABSTRACT: Objective: To compare and investigate the effect of phonopheresis and topical salvadora persica on wound healing in rats. Design: Randomized, controlled trial. Settings: University animal laboratory. Animals: 45 adult albino male rats allocated to A, B and C groups. Interventions: After anesthesia, a wound area of 5cm2 was made on the upper dorsum of all rats. Group A was treated with phonopheresis, with frequency of 1MHz, intensity of 0.5W/cm2 and duty cycle of 40%, group B received sham phonopheresis while group C received sham ultrasonic, and treatment duration for all was six minutes/session/8 sessions. Wounds were captured by digital camera and were measured using trace method. Outcome measures: healing represents decreased in wound surface area. Results: there was a significant sequential reduction in wound surface area throughout 1st, 3rd, 5th and 8th sessions in all three groups. There was significant difference between; mean of W.S.A in group (A) and mean of W.S.A in group (B) at3rd ,5th and 8th sessions as p value (.09), (0.029) and (0.004) respectively, also there was significant difference between; mean of W.S.A in group (A) and mean of W.S.A in group (C) at 3rd, 5th and 8th sessions as p value (0.003),(0.00001) and (0.00001) respectively, while there was significant difference between; mean of W.S.A in group(B) and mean of W.S.A in group (C) at 3rd, 5th and 8th sessions as p value (0.024), (0.00001) and (0.021) respectively. Conclusion: phonophersis and topical salvadora persica gel have satisfied effect on wound healing. In addition, better healing provided by phonopheresis
    Full-text · Article · May 2014 · International Journal of Advanced Research
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