Possible Local Stem Cells Activation by Microcurrent Application in Experimentally Injured Soleus Muscle

Abstract

Background:Severe injuries in skeletal muscle result in muscle weakness that delays recovery and contribute to progressive decline in muscle function. Microcurrent therapy (MCT) is a novel treatment method used in soft tissue injury and tissue regeneration therapy. The regenerative capacity of skeletal muscle tissue resides in satellite cells, the quiescent adult stem cells.Aim:The present work aimed at investigating the relation between microcurrent therapy and local stem cells in regeneration of induced skeletal muscle injury in albino rat.Materials and methods:Twenty six adult male albino rats were divided into Sham group, Injury group (I): subjected to soleus muscle injury and subdivided into subgroups I1 & I2 sacrificed 2 and 4 weeks after injury respectively. Microcurrent group (M): subjected to muscle injury and micro-current was applied. The animals were subdivided into subgroups M1 and M2 sacrificed 2 and 4 weeks after injury. Histological, immunohistochemical and morphometric studies were performed.Results:Atypical fibers widely separated by infiltrating cells and strong acidophilic sarcoplasm with focal vacuolations were found in injury group. In M1 subgroup few atypical fibers were found. In M2 subgroup multiple typical fibers were detected. A significant decrease in the mean area of atypical fibers, a significant increase in the mean area% of alpha SMA+ve cells and that of CD34+ve cells were found in microcurrent group compared to injury group. Conclusion: A definite therapeutic effect of the microcurrent was found on induced skeletal muscle injury. This effect was proved to be related to satellite cell activation.

Low-intensity microcurrent therapy promotes regeneration of atrophied calf muscles in immobilized rabbits

“…In the present study, we found that the number of PCNA and BrdU-positive satellite cells in the atrophied GCM muscle had a significant increase after low-intensity MT compared to high-intensity MT. Although the parameters of MT (8 Hz, 25 μA, 5,000 μA) used in this study were different from those used the in the previous studies, our findings are in agreement with those of earlier studies, in which the electrical stimulation (2–20 Hz, 0.5–20 mA) yielded an effective stimulus to rescue the loss of satellite cells in disused muscle atrophy in mice [29] , and a similar effect was found on muscle satellite cells with other electrical stimulation parameters (0.3 Hz and 10 μA) [16] . In particular, the mitotic activity of satellite cells (myogenic precursor cells) was the first observable phenomenon after the 2-week immobilisation followed by 4 weeks of remobilisation and coincided with the recovery of muscle fibres [19,27] .…”

“…The right GCM muscle was immobilized by cast for 2 weeks. According to the standardised IC procedure, the right knee and ankle of the rabbit were placed in an extended position using a splint made of PVC-plastic, a non-adhesive bandage and an adhesive elastic bandage (Tensoplast ® ; Smith & Nephew Medical, London, UK) [16] . Following the IC, muscle samples from the GCM muscle of the right hind limbs were taken for microscopic evaluation.…”

“…According to the previous studies, when an electric current with an intensity of 100–500 μA was applied to treat muscle damage, the healing process including amino acid transport, triphosphate generation, and protein synthesis. Then healing effect increased by 30%–40% above the control level along with the activation of myogenic precursor cells (satellite cells) [14–16] . On the contrary, when the intensity exceeded 1,000 μA, these bio-stimulatory effects were reversed.…”

Therapeutic effect of microcurrent on calf muscle atrophy in immobilized rabbit

“…Studies have shown that microcurrent below 1,000 μA of electricity was able to increase adenosine triphosphate (ATP) production, protein synthesis, and the activation of myogenic precursor cells (satellite cells). Notably, however, ATP production decreased upon application of 5,000 μA of electricity …”

“…Notably, however, ATP production decreased upon application of 5,000 lA of electricity. [13][14][15] The aim of this study was to assess the effect of MES on the regeneration process of atrophied skeletal muscle and determine whether satellite cells in atrophied skeletal muscle could be activated by MES in a rabbit model system.…”