MENS-associated increase of muscular protein content via modulation of caveolin-3 and TRIM72

Physiological effects of microcurrent and its application for maximising acute responses and chronic adaptations to exercise

Microcurrent is a non-invasive and safe electrotherapy applied through a series of sub-sensory electrical currents (less than 1 mA), which are of a similar magnitude to the currents generated endogenously by the human body. This review focuses on examining the physiological mechanisms mediating the effects of microcurrent when combined with different exercise modalities (e.g. endurance and strength) in healthy physically active individuals. The reviewed literature suggests the following candidate mechanisms could be involved in enhancing the effects of exercise when combined with microcurrent: (i) increased adenosine triphosphate resynthesis, (ii) maintenance of intercellular calcium homeostasis that in turn optimises exercise-induced structural and morphological adaptations, (iii) eliciting a hormone-like effect, which increases catecholamine secretion that in turn enhances exercise-induced lipolysis and (iv) enhanced muscle protein synthesis. In healthy individuals, despite a lack of standardisation on how microcurrent is combined with exercise (e.g. whether the microcurrent is pulsed or continuous), there is evidence concerning its effects in promoting body fat reduction, skeletal muscle remodelling and growth as well as attenuating delayed-onset muscle soreness. The greatest hindrance to understanding the combined effects of microcurrent and exercise is the variability of the implemented protocols, which adds further challenges to identifying the mechanisms, optimal patterns of current(s) and methodology of application. Future studies should standardise microcurrent protocols by accurately describing the used current [e.g. intensity (μA), frequency (Hz), application time (minutes) and treatment duration (e.g. weeks)] for specific exercise outcomes, e.g. strength and power, endurance, and gaining muscle mass or reducing body fat.

Effects of Physical Agents on Muscle Healing with a Focus on Animal Model Research

Skeletal muscle injury is caused by a variety of events, such as muscle laceration, contusions, or strain. Muscle fibers respond to minor damage with immediate repair mechanisms that reseal the cell membrane. On the other hand, repair of irreversibly damaged fibers is achieved by activation of muscle precursor cells. Muscle repair is not always perfect, especially after severe damage, and can lead to excessive fibroblast proliferation that results in the formation of scar tissue within muscle fibers. Remaining scar tissue can impair joint movement, reduce muscular strength, and inhibit exercise ability; therefore, to restore muscle function, minimizing the extent of injury and promoting muscle regeneration are necessary. Various physical agents, such as cold, thermal, electrical stimulation, and low-intensity pulsed ultrasound therapy, have been reported as treatments for muscle healing. Although approaches based on the muscle regeneration process have been under development, the most efficacious physiological treatment for muscle injury remains unclear. In this review, the influence of these physical agents on muscle injury is described with a focus on research using animal models.

Effects of adding post-workout microcurrent in males cross country athletes

Post-exercise microcurrent based treatments have shown to optimise exercise-induced adaptations in athletes. We compared the effects of endurance training in combination with either, a microcurrent or a sham treatment, on endurance performance. Additionally, changes in body composition, post-exercise lactate kinetics and perceived delayed onset of muscle soreness (DOMS) were determined. Eighteen males (32.8 ± 6.3 years) completed an 8-week endurance training programme involving 5 to 6 workouts per week wearing a microcurrent (MIC, n=9) or a sham (SH, n=9) device for 3-h post-workout or in the morning during non-training days. Measurements were conducted at pre- and post-intervention. Compared to baseline, both groups increased (P < 0.01) maximal aerobic speed (MIC, pre = 17.6 ± 1.3 to post=18.3 ± 1.0; SH, pre=17.8 ± 1.5 to post = 18.3 ± 1.3 km^.h^-1) with no changes in V˙O_2peak. No interaction effect per group and time was observed (P=0.193). Although both groups increased (P < 0.05) trunk lean mass (MIC, pre=23.2 ± 2.7 to post=24.2 ± 2.0; SH, pre=23.4 ± 1.7 to post=24.3 ± 1.6 kg) only MIC decreased (pre=4.8 ± 1.5 to post=4.5 ± 1.5, p=0.029) lower body fat. At post-intervention, no main differences between groups were observed for lactate kinetics over the 5 min recovery period. Only MIC decreased (P<0.05) DOMS at 24-h and 48-h, showing a significant average lower DOMS score over 72-h after the completion of the exercise-induced muscle soreness protocol. In conclusion, a 3-h daily application of microcurrent over an 8-week endurance training programme produced no further benefits on performance in endurance-trained males. Nonetheless, the post-workout microcurrent application promoted more desirable changes in body composition and attenuated the perception of DOMS over 72-h post-exercise.

MBNL1-Associated Mitochondrial Dysfunction and Apoptosis in C2C12 Myotubes and Mouse Skeletal Muscle

We explored the interrelationship between a tissue-specific alternative splicing factor muscleblind-like 1 (MBNL1) and peroxisome proliferator-activated receptor-γ coactivator 1-α (PGC-1α), B-cell lymphoma 2 (Bcl-2) or Bcl-2-associated X protein (Bax) in C2C12 myotubes and mouse skeletal muscle to investigate a possible physiological role of MBNL1 in mitochondrial-associated apoptosis of skeletal muscle. Expression level of PGC-1α and mitochondrial membrane potential evaluated by the fluorescence ratio of JC-1 aggregate to monomer in C2C12 myotubes were suppressed by knockdown of MBNL1. Conversely, the ratio of Bax to Bcl-2 as well as the apoptotic index in C2C12 myotubes was increased by MBNL1 knockdown. In plantaris muscle, on the other hand, not only the minimum muscle fiber diameter but also the expression level of MBNL1 and PGC-1α in of 100-week-old mice were significantly lower than that of 10-week-old mice. Furthermore, the ratio of Bax to Bcl-2 in mouse plantaris muscle was increased by aging. These results suggest that MBNL1 may play a key role in aging-associated muscle atrophy accompanied with mitochondrial dysfunction and apoptosis via mediating PGC-1α expression in skeletal muscle.

Probucol recovers pathological damage in viral Myocarditis through improvement of myocardium-related proteins

This study explored the effects of probucol on myocardial injury, oxidative stress, and Cav-3 and Smad3 expression in myocardial tissues by establishing VMC rat models, in order to provide a basis for exploring the mechanism of probucol in treatment of VMC. Sixty rats were randomly divided into control group, model group, probucollowdose group, andprobucol highdose group, with 15 in each group. Except for the control group, rats in each group were intraperitoneally injected coxsackievirus B3 diluent (0.2 ml) to replicate VMC models every 4 days. The results showed that Caspase-3 and Caspase-9, myocardial enzymes, cTn I, and MDA levels in the model group significantly increased (P < 0.05), while the SOD level significantly decreased (P < 0.05); and after probucol treatment, Caspase-3 and Caspase-9, myocardial enzymes, cTn I and MDA levels significantly decreased (P < 0.05), and the SOD level significantly increased (P < 0.05). Compared with the control group, there was an increase in myocardial fibers with significant lesions in the model group, and the pathological scores and the mRNA and protein expression levels of Cav-3 and Smad3 in myocardial cells significantly increased (P < 0.05). Compared with the control group, the myocardial tissue lesions were improved in the probucol low dose group and highdose group, and the pathological scores and the mRNA and protein expression levels of Cav-3 and Smad3 in myocardial cells were significantly reduced (P < 0.05). In conclusion, probucol can significantly improve the pathological damage of myocardial tissue in VMC rats, and its mechanism may be related to improving the expression of myocardium-related proteins Caspase-3 and Caspase-9, inhibiting oxidative stress response, and down-regulating Cav-3 and Smad3 gene expression in myocardial tissue of VMC rats.

Histological aspects of skeletal muscle fibers splitting of C57BL/6NCrl mice

The objective of the current study is to present data on the splitting of skeletal muscle fibers in C57BL/6NCrl mice. Skeletal muscles (m. rectus femoris (m. quadriceps femoris)) from 500 (250 female and 250 male) C57BL/6NCrl mice in the 16th week of life were sampled during autopsy and afterwards standardly histologically processed. Results show spontaneous skeletal muscle fiber splitting which is followed by skeletal muscle fiber regeneration. One solitary skeletal muscle fiber is split, or is in contact with few localized splitting skeletal muscle fibers. Part of the split skeletal muscular fiber is phagocytosed, but the remaining skeletal muscular fiber splits are merged into one regenerating skeletal muscle fiber. Nuclei move from the periphery to the regenerating skeletal muscle fiber center during this process. No differences were observed between female and male mice and the morphometry results document < 1 % skeletal muscle fiber splitting. If skeletal muscular fibers splitting occurs 5 % > of all skeletal muscular fibers, it is suggested to describe and calculate this in the final histopathological report.

The regulatory role of Myomaker and Myomixer-Myomerger-Minion in muscle development and regeneration

Skeletal muscle plays essential roles in motor function, energy, and glucose metabolism. Skeletal muscle formation occurs through a process called myogenesis, in which a crucial step is the fusion of mononucleated myoblasts to form multinucleated myofibers. The myoblast/myocyte fusion is triggered and coordinated in a muscle-specific way that is essential for muscle development and post-natal muscle regeneration. Many molecules and proteins have been found and demonstrated to have the capacity to regulate the fusion of myoblast/myocytes. Interestingly, two newly discovered muscle-specific membrane proteins, Myomaker and Myomixer (also called Myomerger and Minion), have been identified as fusogenic regulators in vertebrates. Both Myomaker and Myomixer-Myomerger-Minion have the capacity to directly control the myogenic fusion process. Here, we review and discuss the latest studies related to these two proteins, including the discovery, structure, expression pattern, functions, and regulation of Myomaker and Myomixer-Myomerger-Minion. We also emphasize and discuss the interaction between Myomaker and Myomixer-Myomerger-Minion, as well as their cooperative regulatory roles in cell-cell fusion. Moreover, we highlight the areas for exploration of Myomaker and Myomixer-Myomerger-Minion in future studies and consider their potential application to control cell fusion for cell-therapy purposes.

Effectiveness of combining microcurrent with resistance training in trained males

Introduction

Microcurrent has been used to promote tissue healing after injury or to hasten muscle remodeling post exercise post exercise.

Purpose

To compare the effects of resistance training in combination with either, microcurrent or sham treatment, on-body composition and muscular architecture. Additionally, changes in performance and perceived delayed onset muscle soreness (DOMS) were determined.

Methods

Eighteen males (25.7 ± 7.6 years) completed an 8-week resistance training program involving 3 workouts per week (24 total sessions) wearing a microcurrent (MIC, n = 9) or a sham (SH, n = 9) device for 3-h post-workout or in the morning during non-training days. Measurements were conducted at pre and post intervention.

Results

Compared to baseline, both groups increased (p < 0.05) muscle thickness of the elbow flexors (MIC + 2.9 ± 1.4 mm; SH + 3.0 ± 2.4 mm), triceps brachialis (MIC + 4.3 ± 2.8 mm; SH + 2.7 ± 2.6 mm), vastus medialis (MIC + 1.5 ± 1.5 mm; SH + 0.9 ± 0.8 mm) and vastus lateralis (MIC + 6.8 ± 8.0 mm; SH + 3.2 ± 1.8 mm). Although both groups increased (p < 0.01) the pennation angle of vastus lateralis (MIC + 2.90° ± 0.95°; SH + 1.90° ± 1.35°, p < 0.01), the change measured in MIC was higher (p = 0.045) than that observed in SH. Furthermore, only MIC enlarged (p < 0.01) the pennation angle of brachialis (MIC + 1.93 ± 1.51). Both groups improved (p < 0.05) bench press strength and power but only MIC enhanced (p < 0.01) vertical jump height. At post intervention, only MIC decreased (p < 0.05) DOMS at 12-h, 24-h, and 48-h after performing an exercise-induced muscle soreness protocol.

Conclusion

A 3-h daily use of microcurrent maximized muscular architectural changes and attenuated DOMS with no added significant benefits on body composition and performance.