• Journal of Animal Science and Technology
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• v.63 no.4
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• pp.673-680
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• 2021

The purpose of this study was to establish a basic principal procedure for the processing of cultured meat. The first stage involved isolating satellite cells from the desired muscle of an animal using enzymatic digestion (i.e., by using proteases, collagenases, and pronases). The second stage involved culturing the isolated muscle satellite cells in a growth medium containing fetal bovine serum and penicillin/streptomycin with growth factors for an optimal period of time. The second stage involved a basic method for the isolated muscle cells to proliferate while sub-culturing to further induce differentiation in gelatin-coated culture dishes with the general culture medium. The third stage involved the induction of differentiation of muscle satellite cells or formation of myotubes using myogenic medium. Lastly, the fourth stage involved the identification of cell differentiation or myotube formation (myogenesis) using fluorescent dyes. Moreover, the principle of these protocols can be applied to perform primary culture of animal cells. This study will assist beginners with the technical aspects of culturing meat (isolation, cultivation, and differentiation of muscle satellite cells as well as identification of myotube formation for myogenesis).

• Journal of Life Science
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• v.30 no.2
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• pp.202-210
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• 2020

As the elderly population increases, it is becoming important to prevent and treat muscle loss caused by aging or disease. Steroidal androgen in the protein assimilation steroid (AAS) system is mainly used to induce muscle improvement, but it is well known that long-term or excessive doses of AAS result in various side effects, although they are prescribed for various muscle and weight loss treatments. Research is therefore underway to explore natural substances that promote muscle renewal with relatively few side effects. However, despite many studies on the improvement of skeletal muscle and the reduction of muscle disease using natural products, there is still a lack of significant clinical results and mechanism studies. The promotion of muscle regeneration through treatment with natural substances typically involves three mechanisms: positive control of the muscle modulating factor (MRF), activation of the protein synthesis mechanism, and inhibition of the protein breakdown mechanism. A study of plant extracts that are known to have muscle neoplasmic stimulation effects, such as black ginseng, plum, and nutmeg, as well as single substances derived from natural products, such as creatine, catechin, and several fatty acids, is therefore described. We also summarize the mechanisms that have been identified so far through which each of these extracts or single materials facilitates muscle regeneration and the signaling pathways that they mediate.

• The Korean Journal of Zoology
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• v.33 no.1
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• pp.108-118
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• 1990

Fibronectin is a glycoprotein found in the extracellular matrix as well as in the serum, and has been known to exert pronouned effed on the myoblast fusion. Our previous studies have suggested that the decrease of fibronectin levels during myogenesis is due to the decreased availability of the receptor for the 28 kDa fragrnent of fibronetin. In the fusion-blocked myoblasts by EGTA, the levels of fibronetin and binding of 28 kDa fragment decreased but far less than the control level. In contrast, the levels of fibronetin and binding of 28 kDa fragment decreased to the control level in the myoblast released from the fusion block. On this account, we suggest that the decrease of fibronetin levels during myoblast fusion is closely associated with the loss or alteration of the receptor for 28 kDa fragment. Mild trypsin treatment decreased the binding of the 28 kDa fragment to the myoblasts significandy. Similarly, the presence of gangliosides in the binding media decreased the binding of the 28 kDa fragment in a dose-dependent manner. Furthermore, gel overlay of 125 I-28 kDa fragment on the SDS-PAGE of the myoblast homogenates revealed that the 28 kDa fragment bound to a 43 kDa protein and to gangliosides as well. These results suggest that myoblast fusion is correlated with decrease of the receptor for the 28 kDa fragment and that the receptor might be a glycoprotein that contains glyco-conjugate found in gangliosides.

• Journal of Ginseng Research
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• v.47 no.6
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• pp.726-734
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• 2023

Background: Skeletal muscles play a key role in physical activity and energy metabolism. The loss of skeletal muscle mass can cause problems related to metabolism and physical activity. Studies are being conducted to prevent such diseases by increasing the mass and regeneration capacity of muscles. Ginsenoside Rg5 has been reported to exhibit a broad range of pharmacological activities. However, studies on the effects of Rg5 on muscle differentiation and growth are scarce. Methods: To investigate the effects of Rg5 on myogenesis, C2C12 myoblasts were induced to differentiate with Rg5, followed by immunoblotting, immunostaining, and qRT-PCR for myogenic markers and promyogenic signaling (p38MAPK). Immunoprecipitation confirmed that Rg5 increased the interaction between MyoD and E2A via p38MAPK. To investigate the effects of Rg5 on prevention of muscle mass loss, C2C12 myotubes were treated with dexamethasone to induce muscle atrophy. Immunoblotting, immunostaining, and qRT-PCR were performed for myogenic markers, Akt/mTOR signaling for protein synthesis, and atrophy-related genes (Atrogin-1 and MuRF1). Results: Rg5 promoted C2C12 myoblast differentiation through phosphorylation of p38MAPK and MyoD/E2A heterodimerization. Furthermore, Rg5 stimulated C2C12 myotube hypertrophy via phosphorylation of Akt/mTOR. Phosphorylation of Akt induces FoxO3a phosphorylation, which reduces the expression of Atrogin-1 and MuRF1. Conclusion: This study provides an understanding of how Rg5 promotes myogenesis and hypertrophy and prevents dexamethasone-induced muscle atrophy. The study is the first, to the best of our knowledge, to show that Rg5 promotes muscle regeneration and to suggest that Rg5 can be used for therapeutic intervention of muscle weakness and atrophy, including cancer cachexia.

• Proceedings of the Zoological Society Korea Conference
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• 1996.10a
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• pp.146.2-146
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• 1996

No Abstract, See Full Text

• Proceedings of the Zoological Society Korea Conference
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• 1996.10a
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• pp.147.2-147
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• 1996

No Abstract, See Full Text

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.158-158
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• 2015

Myoblast are myogenic precursors that proliferate, activate, and differentiate on muscle injury to sustain the regenerative capacity of skeletal muscle; The neuronal isoform of nitric oxide synthase (nNOS, termed also NOS-I) is expressed in normal adult skeletal muscle, suggesting important functions for Nitric oxide (NO) in muscle biology1,2,3. However, the expression and subcellular localization of NO in muscle development and myoblast differentiation are largely unknown. In this study, we examined effects of the nitric oxide generated by a microwave plasma torch, on proliferation/differentiation of rat myoblastic L6 cells. Experimental data pertaining to nitric oxide production are presented in terms of the oxygen input in units of cubic centimetres per minute. The various levels of nitric oxide are observed depending on the flow rate of nitrogen gas, the ratio of oxygen gas, and the microwave power4. In order to evaluate the potential of nitric oxide as an activator of cell differentiation, we applied nitric oxide generated from the microwave plasma torch to L6 skeletal muscles. Differentiation of L6 cells into myotubes was significantly enhanced the differentiation after nitric oxide treatment. Nitric oxide treatment also increase the expression of myogenesis marker proteins and mRNA level, such as myogenin and myosin heavy chain (MHC), as well as cyclic guanosine monophosphate (cGMP), However during the myotube differentiation we found that NO activate oxidative stress signaling erks expression. Therefore, these results establish a role of NO and cGMP in regulating myoblast differentiation and elucidate their mechanism of action, providing a direct link with oxidative stress signalling, which is a key player in myogenesis. Based on these findings, nitric oxide generated by plasma can be used as a possible activator of cell differentiation and tissue regeneration.

• BMB Reports
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• v.48 no.11
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• pp.595-596
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• 2015

Skeletal muscle exhibits a loss of muscle mass and function with age. Decreased regenerative potential of muscle stem/progenitor cells is a major underlying cause of sarcopenia. We analyzed microRNAs (miRNA) that are differentially expressed in young and old myoblasts, to identify novel intrinsic factors that play a degenerative role in aged skeletal muscle. miR-431, one of decreasing miRNAs in old myoblasts, improved the myogenic differentiation when overexpressed in old myoblast, but suppressed their myogenic capability in knockdowned young myoblasts. We found that miR-431 directly binds to 3` untranslated regions (UTR) of Smad4 mRNA, and decreases its expression. Given that SMAD4 is one of the downstream effectors of TGF-β, a well-known degenerative signaling pathway in myogenesis, the decreased miR-431 in old myoblast causes SMAD4 elevation, thus resulting in defective myogenesis. Exogenous expression of miR-431 greatly improved the muscle regeneration in the cardiotoxin-injured hindlimb muscle of old mice by reducing SMAD4 levels. Since the miR-431 seed sequence is conserved in human SMAD4 3'UTR, miR-431 regulates the myogenic capacity of human skeletal myoblasts in the same manner. Our results suggest that age-associated miR-431 is required for the maintenance of the myogenic capability in myoblasts, thus underscoring its potential as a therapeutic target to slow down muscle aging.

• Journal of the Korean Applied Science and Technology
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• v.35 no.2
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• pp.509-518
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• 2018

The purpose of this study was myokine product and role with physical activity and literature review. There is accumulating epidemiological evidence that a physically active life plays an independent role in the protection against type 2 diabetes, cardiovascular disease, colon cancer, dementia and even depression. And myokine has been regarded an important factor of exercise training and brain growth factor for the prevention of Alzheimier's disease. During exercise the release of anti-inflammatory myokine from contracting muscle controled the metabolic response, and IL-4, IL-6, IL-7, IL-10, and IL-15 controled muscle hypertrophy, myogenesis and angiogenenesis. IL-6 promoted the lipid metabolism through AMPK activation. IL-1Ra, IL-10 and sTNF-R inhibited $TNF-{\alpha}$ as the pro-inflammatory cytokine. IL-15 increased the releasing volume from contracting muscle, and promoted the anabolic factor of muscle growth. IL-7 and IL-8 activated the angiogenesis through the more activation of C-X-C receptor signal transmission.

• The Journal of Internal Korean Medicine
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• v.28 no.2
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• pp.333-345
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• 2007

Determination and differentiation of cells in the skeletal muscle lineage is positively regulated by cell-cell contact. differentiation proteins proposed to mediate this effect include both classical MyoD and MEF members : potential interactions between the promyogenic activities of these classes of protein, however, are unknown. We show here that MyoD and MEF, two promyogenic family members that determine to each other in a cis fashion, form ineraction with MyoD- and MEF. These proteins contain myosin heavy chains and are enriched at sites of cell-cell contact between myoblasts, Therefore, In differentiation of MyoD MEF from CST (Chungsimyeonjatang) interact dependently, suggesting that the interactions occur in a cis fashio : consistent with this conclusion, MyoD-mediated differentiation is required for myoblast to occur by CST. Inhibition in myoblasts of a MyoD by STP in its ability to associate with MEF interferes with differentiation as assessed by morphological and transcription level, suggesting that this interaction is functionally important in myogenesis. Also, some of the differentiation-mediated proteins that are required for myogenesis seem to be based on interdependent activities of promyogenic classical SMAD-subfamilly.