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Haraguchi S1, Sakaguchi A2, Yamamoto H2
1Katsuragi Hospital, Kishiwad-shi, Osaka, Japan, 2Hyogo University of Health Sciences, Kobe-shi, Hyogo, Japan
Background: Microcurrent electrical stimulation (MES) involves therapeutic electrical stimulation to accelerate the epithelial wound healing process. However, the clinical evidence to determine whether certain conditions of MES intervention are effective remains insufficient.We therefore focused on growth factors known to accelerate epithelial wound healing, and analyzed whether expression levels are changed with MES. We believe that the most effective MES intervention conditions may be identifiable using changes in gene expression levels of MES responsive genes as indicators.
Purpose: The purpose of our study was to examine whether a single session of MES accelerates the epithelial wound healing process and/or induces changes in expression levels of related genes.
Methods: In this study, we created two wounds at bilaterally symmetrical positions about the midline on the backs of six Wistar rats, and performed MES intervention (500 µA, 0.3 Hz, 30 min, AC) immediately after wounding only on the right-side wound. After MES intervention, total RNA was purified from skin tissue of both right- and left-side wounds.To measure gene expression levels of growth factors involved in epithelialization, we performed real-time polymerase chain reaction (RT-PCR). Expression levels of each gene for the right-side wound were compared with the left-side wound as a control. Wilcoxon matched-pairs signed-ranks testing was performed for statistical analysis and the level of significance was set at less than 5%.
Results: We found that expression levels of epidermal growth factor (EGF) and its receptor EGF-R were significantly increased by 2.5- and 11.6-fold following a single session of MES.
Conclusion(s): The biological role of EGF has already been reported as the promotion of epithelization in the early stage of the wound-healing process, through activation of EGF-R-dependent intracellular signaling. This study showed that a single session of MES was effective for inducing EGF gene expression. Furthermore, EGF-R gene expression was induced. These results suggested that single MES has an accelerating effect not only for wound healing, but also for epithelization, through ligand-receptor interactions in a synergistic manner. The effect of MES in accelerating wound healing may play an important role in the field of physical therapy, which handles injuries such as after orthopedic interventions and grazes. This research provides evidence for the validity of MES in physical therapy.
Implications: This study only showed changes in amounts of EGF and EGF-R mRNA. Future studies need to confirm whether levels of proteins for these factors are also increased, and whether histological analysis shows acceleration of epithelial wound healing.
Keywords: Microcurrent Electrical Stimulation, Wound Healing, mRNA
Funding acknowledgements: The authors have no conflicts of interest directly relevant to the content of this article.
Purpose: The purpose of our study was to examine whether a single session of MES accelerates the epithelial wound healing process and/or induces changes in expression levels of related genes.
Methods: In this study, we created two wounds at bilaterally symmetrical positions about the midline on the backs of six Wistar rats, and performed MES intervention (500 µA, 0.3 Hz, 30 min, AC) immediately after wounding only on the right-side wound. After MES intervention, total RNA was purified from skin tissue of both right- and left-side wounds.To measure gene expression levels of growth factors involved in epithelialization, we performed real-time polymerase chain reaction (RT-PCR). Expression levels of each gene for the right-side wound were compared with the left-side wound as a control. Wilcoxon matched-pairs signed-ranks testing was performed for statistical analysis and the level of significance was set at less than 5%.
Results: We found that expression levels of epidermal growth factor (EGF) and its receptor EGF-R were significantly increased by 2.5- and 11.6-fold following a single session of MES.
Conclusion(s): The biological role of EGF has already been reported as the promotion of epithelization in the early stage of the wound-healing process, through activation of EGF-R-dependent intracellular signaling. This study showed that a single session of MES was effective for inducing EGF gene expression. Furthermore, EGF-R gene expression was induced. These results suggested that single MES has an accelerating effect not only for wound healing, but also for epithelization, through ligand-receptor interactions in a synergistic manner. The effect of MES in accelerating wound healing may play an important role in the field of physical therapy, which handles injuries such as after orthopedic interventions and grazes. This research provides evidence for the validity of MES in physical therapy.
Implications: This study only showed changes in amounts of EGF and EGF-R mRNA. Future studies need to confirm whether levels of proteins for these factors are also increased, and whether histological analysis shows acceleration of epithelial wound healing.
Keywords: Microcurrent Electrical Stimulation, Wound Healing, mRNA
Funding acknowledgements: The authors have no conflicts of interest directly relevant to the content of this article.
Topic: Electrophysical & isothermal agents
Ethics approval required: Yes
Institution: Hyogo University of Health Sciences
Ethics committee: Animal Care and Use Committee
Ethics number: 2017-11
All authors, affiliations and abstracts have been published as submitted.
