Combined Pulsed Magnetic Field and Radiofrequency Electromagnetic Field Enhances MMP-9, Collagen-4, VEGF Synthesis to Improve Wound Healing Via Hif-1α/eNOS Pathway.

Abstract

The blood supply of the tissue is very important in the acceleration of wound healing. Radiofrequency electromagnetic field (RF) and the pulsed magnetic field (PMF) increase vasodilation to contribute wound healing. The aim of this study was to evaluate the effects of RF and PMF on wound healing via hypoxia-inducible factor-1 alpha (Hif-1α)/endothelial nitric oxide synthase (eNOS) pathway. Forty-eight rats were divided into 4 groups as sham (wound created only), PMF (27.12MHz, 12 times a day at 30-min intervals), RF (0.5 mT, continuously) and PMF + RF groups. Wounds were created at 1.5 × 1.5cm size to the dorsal region, and animals were put into unit. Six animals were killed on days 4 and 7; wound tissues were collected for histopathological, immunohistochemical as collagen-4, cytokeratin, matrix metalloproteinase-9 (MMP-9), vascular endothelial growth factor (VEGF) staining and Hif-1α/eNOS/VEGF expressions. On day 4, in addition to increasing VEGF and MMP-9 stainings, connection between intact tissue and scar tissue which was stronger in the RF- and PMF-applied groups was observed. On day 7, epithelization started; inflammatory reaction decreased; collagen production, cytokeratin, VEGF and MMP-9 expression enhanced, especially in the RF + PMF applied group. eNOS, Hif-1α and VEGF expression levels were found to be significantly highest in both days of RF + PMF-applied group. This study revealed that both in vitro RF and PMF applications can cause notable changes in factors that are required for tissue repair on wound healing such as epithelization, connective tissue formation, collagen production and angiogenesis via vasodilatory Hif-1α/eNOS pathway and VEGF signaling. This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .