Role of sensory and motor intensity of electrical stimulation on fibroblastic growth factor-2 expression, inflammation, vascularization, and mechanical strength of full-thickness wounds

Abstract

Abstract-Electrical stimulation (ES) profoundly affects angiogenesis by modulating the production of angiogenic factors. We evaluated the effect of sensory (direct current, 600 microamperes) and motor (monophasic pulse current, 2.5 to 3 milliamperes, 300-microsecond pulse duration, 100 Hz) intensities of cathodal current on the release of fibroblastic growth factor-2 (FGF-2) at the wound site and also the biomechanical and histological properties of healed skin. Ninety-six male, SpragueDawley rats were randomly assigned into one control and two experimental groups. A full-thickness skin incision was made on the dorsal region of each animal. The experimental groups received 10 sessions of ES (sensory or motor) for 1 hour per day every other day. The results showed that FGF-2 levels in the sensory group were significantly greater than in the other groups on the third day. In the motor group, FGF-2 levels were significantly decreased compared with the control group. There were no significant differences between the normalized ultimate strength and stiffness in the groups, but they tended to be higher in the motor ES group. We conclude that the application of sensory ES during the early stage of wound healing may have a beneficial effect on wound healing by inducing the release of angiogenic factors and decreasing the duration of the inflammation phase.

Effect of low-intensity direct current on expression of vascular endothelial growth factor and nitric oxide in diabetic foot ulcers

“…Several investigations have reported that ES can enhance angiogenesis by the upregulation of angiogenic factors, such as VEGF and FGF-2 [14,16,33]. Morris et al reported that ES (square wave pulsed direct current, 11 mA amplitude, 40 ms interpulse interval, 5 or 110 µs pulse duration) induced a significant increase in VEGF level in ischemic wounds in the ears of rabbits [15].…”

“…Morris et al reported that ES (square wave pulsed direct current, 11 mA amplitude, 40 ms interpulse interval, 5 or 110 µs pulse duration) induced a significant increase in VEGF level in ischemic wounds in the ears of rabbits [15]. Asadi et al reported that applying cathodal direct current at sensory intensity induces significant enhancement of VEGF [14] and FGF-2 [33] levels in incisional wounds. In a clinical study, Bevilacqua et al investigated the effect of frequency-modulated ES and TENS on the release of VEGF in diabetic and nondiabetic subjects.…”

The efficacy of electrical stimulation in experimentally induced cutaneous wounds in animals

“…The ES modality is less of a factor with regards to angiogenesis compared to wound closure and tensile strength with only a benefit of DC noted over AC . Sensory threshold current intensity appears more beneficial compared to higher current intensities and cathode is superior to anode stimulation with respect to neo‐vascularization…”

“…With ES augmenting all stages of wound healing, it may provide the necessary key to optimizing wound healing in animals. It may help to avoid fibroproliferative disorders such as EGT by downregulating inflammation through inhibition of cytokine release, improvement of tissue oxygenation and coordination of angiogenesis . However, there are concerns that ES could be detrimental and drive granulation tissue formation and exacerbate such conditions by stimulating an over‐exuberant angiogenic response.…”

“…It was concluded that this increase in VEGF may facilitate angiogenesis and explain the enhanced wound healing seen with sensory intensity ES. In a subsequent study, a similar protocol was used to investigate the effect of ES on the expression of fibroblastic growth factor‐2 (FGF‐2), a direct mediator of angiogenesis . It was discovered that FGF‐2 levels in the sensory group were significantly greater than in the other groups on day 3, and the authors suggested, based on these two studies, that FGF‐2 may induce the upregulation of VEGF and, in turn, promote angiogenesis.…”