Histological Observation of Acute Inflammation During Wound Healing in Mice Using Low-Frequency Electromagnetic Field (LF-EMF) Therapy

Abstract

Background and Objective: Electromagnetic Field (EMF) therapy has emerged as a non-invasive approach to enhance wound healing, yet its effects on the acute inflammatory phase remain unclear. This study aimed to assess the impact of low-frequency EMF (LF-EMF) on wound healing in mice, focusing on this phase.

Materials and Methods: Eighteen mice were divided into two groups: The LF-EMF-treated and control. A full-thickness wound was created on each mouse, with treatment (LF-EMF: 0.8 mT, 15 Hz, 15 min. Control: sham-exposure) administered daily from day 1 to 6 post-wounding.

Results: LF-EMF treatment consistently showed higher percentage reduction in wound area compared to the control group at all time points. The inflammatory response resolved quickly in the LF-EMF group compared to the control group as reflected by a steady decline in neutrophil percentage and remarkably low percentage by Day 6 compared to the control. Monocyte percentages increased gradually in LF-EMF-treated wounds, while lymphocytes declined from day 1 to 3 in both groups before rising again from Day 4 onward, although LF-EMF group was more pronounced. The H&E staining revealed that LF-EMF exposure accelerates wound healing dynamics, demonstrating enhanced angiogenesis, rapid fibrin resolution and early collagen deposition compared to the control group. Masson’s trichrome staining further confirmed increased fibroblast migration and elevated cellularity within the granulation tissue. By day 6, the extracellular matrix displayed improved structural integrity with collagen fibres appearing denser, more aligned and morphologically mature.

Conclusion: These findings underscore the capacity of LF-EMF to modulate key reparative pathways by promoting cellular activation, amplifying fibroproliferative responses and facilitating efficient matrix remodelling.