• Journal of Life Science
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• v.20 no.4
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• pp.572-577
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• 2010

The purpose of this study was to find out the Bcl-2 (B-cell leukemia/lymphoma-2), Bax, and caspase-3(cysteine-aspartic proteases-3) protein expression in soleus and EDL muscle according to treadmill exercise intensity in 60 week-old SD rats. The SD rats were randomly divided into four groups (n=10 in each group): control (CON), low intensity exercise (LE), moderate intensity exercise (ME), and high intensity exercise (HE). The exercise was given to the rats for 8 wk, 5 day/wk. The animals underwent treadmill exercise at intensities of 30 min at 8 m/min for the LE group, 15 min at 16 m/min for the ME group, and 9 min at 24 m/min for the HE group. The results were as follows: the expression of Bcl-2 protein was lowest in the HE group and the expression of Bax protein was highest in the HE group. The expression of caspase-3 (cleaved form) protein was observed in the HE group. For the different types of muscle fiber, Bcl-2 protein expression in the soleus muscle was decreased in all groups. Bax protein expression in the soleus muscle was increased in the HE group only. Bcl-2 protein expression in the EDL muscle was decreased in the HE group, and Bax protein expression in the EDL muscle was increased in the ME and HE groups. Consequently, the protein expression related to the aged rats shows a difference according to the intensity of exercise. In addition, caspase-3 protein expression appeared in the HE group; however, in all amounts of intensity, DNA fragmentation was not observed. Therefore, apoptosis on skeletal muscles of aged mice can be intervened with optimal exercise. On the other hand, high intensity exercise can potentially accelerate the apoptosis of muscle fiber in aged rats.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.4
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• pp.457-463
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• 2016

The goal of this work was to investigate the correlations between MyHC mRNA transcription and their corresponding protein expressions in porcine longissimus muscle (LM) during postnatal growth of pigs. Five DLY ($Duroc{\times}Landrace{\times}Yorkshire$) crossbred pigs were selected, slaughtered and sampled at postnatal 7, 30, 60, 120, and 180 days, respectively. Each muscle was subjected to quantity MyHCs protein contents through an indirect enzyme-linked immunosorbent assay (ELISA), to quantity myosin heavy-chains (MyHCs) mRNA abundances using real-time polymerase chain reaction. We calculated the proportion (%) of each MyHC to total of four MyHC for two levels, respectively. Moreover, the activities of several key energy metabolism enzymes were determined in LM. The result showed that mRNA transcription and protein expression of MyHC I, IIa, IIx and IIb in LM all presented some obvious changes with postnatal aging of pigs, especially at the early stage after birth, and their mRNA transcriptions were easy to be influenced than their protein expressions. The relative proportion of each MyHC mRNA was significantly positively related to that of its corresponding protein (p<0.01), and MyHC I mRNA proportion was positively correlated with creatine kinase (CK), succinate dehydrogenase (SDH), malate dehydrogenase (MDH) activities (p<0.05). These data suggested that MyHC mRNA transcription can be used to reflect MyHC expression, metabolism property and adaptive plasticity of porcine skeletal muscles, and MyHC mRNA composition could be a molecular index reflecting muscle fiber type characteristics.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.9
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• pp.1244-1249
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• 2010

Comparisons of properties between skeletal ryanodine receptor 1 (sRyR1)-heterozygous-mutated and normal types of meat were carried out in pigs using PSE (pale, soft and exudative) meat found during the butchering process. All samples considered to be PSE meat showed irregular running and disorder of the muscle fibers and a wider inter-fiber space upon light microscopic observation. Electron microscopy revealed disintegration, twisting, and disorder of the myofibril arrangement and elimination of the Z line in PSE meat, compared with normal meat. Meat property tests demonstrated greater decreases in water holding capacity, moisture and sarcoplasmic protein, and higher $L^*$ values for the meat color index in PSE meat than in normal meat, but there were no differences in these factors between genetically normal and sRyR1-heterozygous PSE meat. On the other hand, higher $a^*$ and $b^*$ values were observed in sRyR1-heterozygous than in normal PSE meat, and similar alterations to the a* value were observed in terms of the amount of myoglobin and density of the 17-kDa protein band, corresponding to the molecular mass of myoglobin, on SDS-PAGE gels. These results suggest that sRyR1-heterozygous PSE pork contains much more myoglobin than genetically normal PSE meat.

• Journal of Physiology & Pathology in Korean Medicine
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• v.22 no.6
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• pp.1454-1461
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• 2008

In oriental medicine, it is known that Eucommiae Cortex (EC) has strengthening and rehabilitative effects on the bone-muscle dysfunction. This study aimed to evaluate the effect of EC on the skeletal muscle atrophy. The muscle atrophy was induced by unilateral transection of the sciatic nerve in Sprague-Dawley rats. EC (water-extract, 170mg/100 g body weight) was treated once a day for 12 days. In this study, the effect of EC examined the muscle weight of hind limb, cross section areas of muscle fibers, fiber type compositions, apoptosis related factors (Bax and Bcl-2). EC reduced muscle atrophy in soleus (SOL), medial gastrocnemius (MGT), extensor digitorum longus, and tibialis posterior significantly in the damaged hind limb. EC increased type-I muscle fibers and decreased type-II muscle fibers significantly in SOL of the damaged hind limb. EC enlarged cross section areas of type-I and type-II muscle fibers significantly in SOL. EC enlarged cross section areas of type-I and type-II muscle fibers significantly in. EC reduced apoptotic nuclei and atrophic muscle fibers in SOL and MGT. EC reduced Bax positive muscle nuclei in SOL and MGT. EC up-regulated Bcl-2 positive muscle fibers in SOL and MGT. These results suggest that EC has an anti-atrophic effect and anti-apoptotic effect against myonuclear apoptosis induced by the peripheral nerve damage.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.5 no.1
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• pp.59-71
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• 2007

The purpose of this study was to study for the change of neural adaptation by muscle contraction force when neuromuscular electrical stimulation(NMES) was applied. Sixteen subjects(8 male, 8 female) without neuromuscular disease volunteered to participate in the study. All subjects were divided into two subgroups: control(no electrical stimulation) group, NMES(50% maximal voluntary isometric contraction) group. NMES training program was performed in the calf muscle over three times a week for 12 weeks. Before and after experiment MVIC of ankle plantar flexor was measured by use of dynamometer. H-reflex and V-wave in tibial nerve were measured. The following results were obtained; MVIC and V/Mmax ratio were significantly increased in the electrical stimulation groups. However, H/Mmax ratio was not changed. It was closely relationship between MVIC and V/Mmax ratio. In this study, the effect of neural adaptation of central neural adaptation was found in this study. Accordingly, NMES means not only a change of muscle fiber and skeletal muscle volume but also a effect of neural adaptation of central neural drive. Also, it was found that there was closely relationship between MVIC and neural adaptation of central neural drive by NMES.

• Journal of fish pathology
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• v.20 no.2
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• pp.129-137
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• 2007

Skeletal deformity in hatchery-reared river puffer (Takifugu obscurus) fingerlings occurred. The vertebral abnormality was recognized with naked eyes 80 days after hatching. Affected fish had a good appetite but no clinical signs were found except the vertebral abnormality. As more than 90% of the hatchery-reared fish exhibited vertebral abnormality, the fingerlings could not be used for commercial seeds any more. Morphological changes in the vertebrate and the swim bladder were observed with a soft X-ray. Histopathological changes on the caudal muscle around the deformed vertebrae, gill, and spleen were also examined to clarify the cause of the deformity. Spinal curvature occurred between vertebrae 10 and 12, but any malfunction of the swim bladder was not found. The diameters of the muscle fibers around the deformed vertebrae were much smaller and more irregular than those in normal fish, and the gabs between the fiber bundles were greatly enlarged. No evidence of inflammation response was found in the muscle layer. In the hatchery, feed was putting at the position of water inflow, which might attract the fingerings to move toward the feed in spite of incomplete development of their caudal muscle fibers. From these results, it is suggested that the high speed of water current in rearing aquaria might be associated with the development of vertebral abnormality.

• Journal of Veterinary Clinics
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• v.24 no.2
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• pp.244-246
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• 2007

Clinical and histopathologic features of idopathic polymyositis in twenty-month-old Alaskan malamute dog are described. The clinical signs were progressive exercise intolerance with acute exacerbation of weakness, muscle atrophy, synchronous pelvic limb gait, short stiff steps and tip-toeing as like walking on eggshells. Physical and clinical examination revealed no evidence of neurologic, skeletal and secondary muscular disorders associated with other diseases. Therefore muscle biopsy was performed at the most severe muscle atrophy lesions to confirm by histopathology. Histopathologic findings documented mononuclear cell infiltration and necrosis of muscle fiber and it was diagnosed as idiopathic polymyositis. Initial treatment was focused on pain relief. Prednisone at immunosuppressive dose (2 mg/kg) was administered orally twice daily. After 3 weeks of starting treatment, the patient showed improvement of gait, appetite, exercise as well as gradually return to normal state of hematologic and serum chemistry profiles.

• Journal of Life Science
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• v.21 no.8
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• pp.1149-1155
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• 2011

Myostatin (MSTN) belongs to the transforming growth factor-${\beta}$ superfamily or growth and differentiation factor 8 (GDF-8), and functions as a negative regulator of skeletal muscle development and growth. Previous studies in mammals have suggested that myostatin knock-out increased muscle mass and decreased fat content compared to those of the wide type. Recently, several studies on myostatin have beenconducted on the block myostatin signal pathway with myostatin antagonists and the MSTN regulation with RNAi to control myostatin function. This study was performed to analyze growth and muscle alteration of Oncorhychus masou by treatment with recombinant myostatin prodomains derived from fish. We designed myostatin prodomains derived from P. olivaceus (pMALc2x-poMSTNpro) and S. schlegeli (pMALc2x-sMSTNpro) in a pMALc2x expression vector, and then purified the recombinant proteins using affinity chromatography. The purified recombinant proteins were treated in O. masou through an immersion method. Recombinant protein treated groups did not show a significant difference in weight, protein, or lipid composition compared to the control. However, there was a difference in the average number and area for histological analyses in the muscle fiber. At twelve and twenty-two weeks from the initial treatment, there were differences in averagefiber number and area between the 0.05 mg/l treated-group and the control, but the numbers were similar to those of the control during the same time period. At twelve weeks, however, 0.2 mg/l treated-group had an increase in average fiber number and decrease in average fiber area compared to the control. At twenty-two weeks, the pMALc2x-sMSTNpro 0.2 mg/l treated-group was induced and showed a decrease in average fiber number and increase in average fiber area. The results between twelve and twenty-two weeks showed that the fiber numbers had decreased, whereas average fiberarea had increased due to sMSTNpro. It is understood that the sMSTNpro induced only hyperplasia at twelve weeks, after which it induced hypertrophy. Recombinant myostatin prodomains derived from fish may induce hyperplasia and hypertrophy in O. masou depending upon the time that has elapsed.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.5
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• pp.697-702
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• 2015

While athletic abilities such as speed, endurance and recovery are important in the horse, genes related to these abilities have not been extensively investigated. Here, we characterized the horse peroxisome proliferator-activated receptor delta ($PPAR{\delta}$) gene and analyzed the expression of $PPAR{\delta}$ during exercise. $PPAR{\delta}$ is a known regulator of ${\beta}$-oxidation, muscle fiber transformation, and running endurance. Through evolutionary analysis using the synonymous and non-synonymous mutation ratio, it was revealed that positive selection occurred in the horse $PPAR{\delta}$ gene. Two important domains related to nuclear hormone receptors, C4 zinc finger and ligand binding domain, were also found to be conserved well in horse $PPAR{\delta}$. Horse $PPAR{\delta}$ was expressed ubiquitously in many tissues, but the expression level was various depending on the tissues. In the skeletal muscle, $PPAR{\delta}$ increased about 2.5 folds after 30 min of exercise. Unlike in muscle, the increase of $PPAR{\delta}$ expression was observed at 60 min but not 30 min of exercise in leukocytes. This finding might be useful for testing the endurance of horse using blood samples. Conclusively, the horse $PPAR{\delta}$ gene is evolutionarily conserved well and can be used as a biomarker of endurance in horse.

• Journal of Nutrition and Health
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• v.56 no.6
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• pp.602-614
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• 2023

Purpose: The balance between synthesis and degradation of proteins plays a critical role in the maintenance of skeletal muscle mass. Mitochondrial dysfunction has been closely associated with skeletal muscle atrophy caused by aging, cancer, and chemotherapy. Polygalacin D is a saponin derivative isolated from Platycodon grandiflorum (Jacq.) A. DC. This study aimed to investigate the effects of polygalacin D on myoblast differentiation and muscle atrophy in association with mitochondrial function in in vitro and in zebrafish models in vivo. Methods: C2C12 myoblasts were cultured in differentiation media containing different concentrations of polygalacin D, followed by the immunostaining of the myotubes with myosin heavy chain (MHC). The mRNA expression of markers related to myogenesis, muscle atrophy, and mitochondrial function was determined by real-time quantitative reverse transcription polymerase chain reaction. Wild type AB^* zebrafish (Danio rerio) embryos were treated with 5-fluorouracil, leucovorin, and irinotecan (FOLFIRI) with or without polygalacin D, and immunostained to detect slow and fast types of muscle fibers. The Tg(Xla.Eef1a1:mitoEGFP) zebrafish expressing mitochondria-targeted green fluorescent protein was used to monitor mitochondrial morphology. Results: The exposure of C2C12 myotubes to 0.1 ng/mL of polygalacin D increased the formation of MHC-positive multinucleated myotubes (≥ 8 nuclei) compared with the control. Polygalacin D significantly increased the expression of MHC isoforms (Myh1, Myh2, Myh4, and Myh7) involved in myoblast differentiation while it decreased the expression of atrophic markers including muscle RING-finger protein-1 (MuRF1), mothers against decapentaplegic homolog (Smad)2, and Smad3. In addition, polygalacin D promoted peroxisome proliferator-activated receptor-gamma coactivator (Pgc1α) expression and reduced the level of mitochondrial fission regulators such as dynamin-1-like protein (Drp1) and mitochondrial fission 1 (Fis1). In a zebrafish model of FOLFIRI-induced muscle atrophy, polygalacin D improved not only mitochondrial dysfunction but also slow and fast muscle fiber atrophy. Conclusion: These results demonstrated that polygalacin D promotes myogenesis and alleviates chemotherapy-induced muscle atrophy by improving mitochondrial function. Thus, polygalacin D could be useful as nutrition support to prevent and ameliorate muscle wasting and weakness.