Effects of sensory and motor cathodal electrical stimulatons on the injury potential and biomechanical properties of acute skin full-thickness wound in rats

Introduction: The aim of the present study was to investigate the effects of sensory and motor cathodal electrical stimulation (ES) on the injury potential, wound closure time and biomechanical properties of acute full-thickness wound in rats.Materials and Methods: Thirty healthy male Sprague-Dawley rats were randomly assigned to either a control, a sensory [direct current (DC), 600 μA] or a motor (monophasic current, pulse duration 300 μs, 100 Hz, 2.5-3 mA) stimulation group. A 2.5 cm full-thickness skin incision was made on each animal's dorsal region. The stimulation groups received ES for 1 h/day every other day. Wound surface area and differential skin surface potential were measured on the first day and again until the 21st day, every other day. On the 21st day, uniaxial tensile test was carried out and biomechanical properties including stress, strain, E modulus and area under load –deformation curve were measured.Results: Skin potential returned to basal level on the 15th day for the sensory stimulation and control group, and on the 17th day for the motor stimulation group. The wound surface area was closed on the 15th day for the sensory stimulation group whereas this was observed on the 17th day for the motor stimulation and control groups. The motor intensity stimulation could not improve the biomechanical properties of the repaired wound.Conclusion: It seems that the mechanical environment induced by motor intensity of electrical stimulation cannot simulate the role of normal daily stress and strain for the maturation of collagen fibers and their cross links.Keywords: Cathodal electrical stimulation, Motor intensity, Sensory intensity, Tensile strength, Injury potential