Focused Electric Field Technology: A Novel Myoelectrical Stimulation Technology for Noninvasive Aging Muscle Rejuvenation

Abstract

Background: Myoelectrical stimulation improves muscle function and reduces muscle atrophy and aging. However, research on the mechanism underlying its cosmetic effect remains limited.

Aims: The aim of this study was to evaluate the cosmetic effects of the myoelectrical stimulation provided by the wearable intelligent flexible beauty device and its focused electric field technology (FEFT) on facial skin and muscle rejuvenation.

Patients/methods: We conducted a single-blind, randomized, self-controlled clinical efficacy experiment on 31 female volunteers using the device. Using an FEFT-based platform, mice with d-galactose-induced skeletal muscle aging were subjected to surface myoelectrical stimulation of the gastrocnemius. Immunohistochemical analysis of skeletal muscles and protein immunoblotting were used to analyze the effects of FEFT.

Results: After 14 days of use, facial skin elasticity significantly increased, wrinkle firmness significantly decreased, and the lift height of the upper eyelid and eye corner angle significantly increased in the volunteers. Clinical evaluation showed improvements in the drooping of the upper eyelid and eye bags. Self-evaluation questionnaires indicated alleviation of facial wrinkles. These improvements were more pronounced after 28 days. In mice, FEFT alleviated aging-induced muscle fiber atrophy, muscle fiber cross-sectional area reduction, and muscle satellite cell loss. FEFT also increased the expression of myogenic factors, including myogenic differentiation 1 (MYOD1).

Conclusions: FEFT exerted a skin-tightening effect by initiating myogenic processes and increasing the transformation of muscle satellite cells. Our research promotes the development of FEFT-based medical rehabilitation or cosmetic anti-aging products and provides a foundation for further application and comprehensive efficacy evaluation in human clinical settings.

Keywords: clinical evaluation; muscle aging; muscle satellite cells; myoelectrical stimulation; myogenic regulatory family; wearable electronic devices.

FIGURE 1

Application site of test product. Electrodes are mainly applied on periorbital area (A). Illustration of instrumental measurement analysis area (Green area with arrow) (B).

FIGURE 2

Myoelectrical stimulation system. In the human efficacy test, flexible surface electrodes were applied on subjects' face (A). When muscles are relatively flat and smooth, there are uniform electric fields (B). The flexible material texture helps the electrode slice completely fit the skin, making the stimulation of certain muscles more precise and stronger. They selectively induce contractions on a large scale of certain small delicate muscles in the face (C). Myoelectrical stimulation process of mouse experiment (D). Mice were fixed on the operating table with inhalation anesthesia, and their hairs on treated skin areas were removed with hair removal cream. Surface electrodes were from acupuncture needles with modifications (E). Stimulator (F). Oscilloscope (G).

FIGURE 3

FEFT improves facial skin elasticity, firmness, and periocular muscle toning. Skin elasticity and firmness were measured by Cutometer, PA580. The parameters R2 (A) and R5 (B) were used as the basis for judging skin elasticity, and F4 (C) was used to evaluate skin firmness. The improvement of periocular muscle toning reflected in lift height of upper eyelid, eye corner angle, grading of drooping of the upper eyelid, and grading of eye bag. Lift height of upper eyelid was measured by capturing facial images using VISlA and analyzing with image analysis software (D). Eye corner angle was obtained by capturing facial images using VISIA and then analyzing with image analysis software (E). Drooping of the upper outer eyelid grade and eye bag grade were obtained by dermatologists (F and G). Evaluation was carried out as per standard image of “Drooping of the upper outer eyelid” grade of 0–6 (Table 1) and eye bag grade of 0–6 (Table 2). The lower the grade were, the lighter the drooping of the upper outer eyelid and the lighter eye bag would. Besides, individual questionnaires were performed and the results were shown in Table 3 and information details of all volunteers were shown in Table 4. Differences analysis between the baseline value (Day 0) and the measured values (Day 14 and Day 28) was performed by repeated‐measured ANOVA test, the sample size was 31. They were marked by p < 0.05* p < 0.01** and p < 0.001***.

FIGURE 4

Modeling and myoelectrical stimulation did not cause significant stress weight loss (A), and FEFT alleviates D‐galactose‐induced muscle fiber atrophy and satellite cell loss. Histopathological sections of skeletal muscles (H&E), and statistical analysis of CSA of ten visual fields randomly picked from each group (B), scale bar: 100 μm. Localization and expression level of sarcomeric alpha actinin, and statistical analysis of protein expression in situ of ten visual fields randomly picked from each group (C), scale bar: 100 μm. Statistical analyses were performed using GraphPad Prism Version 8.3. All results are expressed as mean ± SD. Comparisons between groups in animal experiments were performed using Two‐tailed student t‐test. p < 0.05*and p < 0.01**.

FIGURE 5

FEFT increases MYOD1 expression in skeletal muscles of induced aging mice. Changes of transcription level in MyoD1 and Myf5 (A), and expression levels of myogenesis‐related proteins MYOD1 and MYF5 (B).