• Applied Microscopy
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• 제25권4호
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• pp.26-51
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• 1995

The present study was designed to examine effect of long term weight-training on aging atrophy in the rat skeletal muscle. Male rats of 8, 15, and 24 month old were used. Each age groups included control and weight-training for 5 months by using body press apparatus. The histo- and cytochemical, ultrastructural and stereological changes in aging skeletal muscles of the rat were observed in the present study. During the training period the body weight and muscular weight in all groups except the rectus femoris and the gastrocnemius in young age groups remained constant, but muscular weights were increased in the rectus femoris and the gastrocnemius muscles in young age groups. In trained rat, the volume density of muscle fiber type IIA and IIB were increased, but those of type IIC was decreased. Type I remained constant in 8 and 15 month old age groups, but reduced in the tibialis anterior and the gastrocnemius muscles in the 24 month old groups. Some histotological and ultrastructural changes associated with age were found: numerical increase of cytiplasmic vacuoles, lysosomes, lipofuscins, and irregularity of myofibrils. At 24 month old groups some unusual formation of contraction band and muscle splitting were observed. After weight-training, ultrastructural degenerative changes occured in the type I muscle fiber, such as splitting of muscle fiber, disorganization of myofilaments, swelling of mitochondria, accumulation of many lipid droplets, appearance of many lysosomes and residual bodies and necrotic fibers, in the old age groups. But, in the type II muscle fibers hypertrophy of muscle fiber appeared without any noticible damage as the type I. The activities of $Mg^{++}$ -ATPase decreased with age and this enzyme activities in the trained rat were significantly decreased with age. Activities of the acid phosphatase were increased with age and significantly in the trained rat. In stereological analysis, volume density of the myofibrils and the tubular system were increased, on the other hand there mitochondrial capacity was decreased. These experimental results suggested that old rats are not susceptible to be affected by weight-training as young rats, and that physical capacity of the rats must be considered when old rats are exercised for training.

• 생명과학회지
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• 제23권12호
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• pp.1509-1515
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• 2013

'지질독성'이라는 용어는 근육과 같은 지방세포가 아닌 조직에서 여분의 지질 축적이 어떻게 세포의 기능저하와 괴사를 유도하는지를 설명하는데 사용되어 왔다. 고지방을 투여한 근세포 배양에서 지질독성이 확인된 바는 있지만, 생체 내 시험에서, 특히 지질독성에 의해 대사적으로 영향을 받는 Type-I 근육에서 이러한 결과가 확인된 바는 없다. 이 연구의 목적은 고지방식이가 쥐의 Type-I 근육의 형태학적 변화와 세포사멸 단백질 발현에 어떠한 영향을 미치는지를 밝히는 것이다. 이를 위해 6주간 고지방식이와 일반식이를 섭취한 쥐의 Type-I 근육 내 지질축적, 염증반응, 핵 침윤현상, cleaved PARP 단백질 발현을 각각 Oil Red O staining, H & E staining, Western blot 을 이용하여 비교 분석하였다. 6주 후 고지방식이 집단에서 지질축적, 염증반응, 핵 침윤현상, cleaved PARP 단백질 발현이 일반식이 집단에서 유의하게 증가하였다. Type-I 근육량은 일반식이 집단에 비해서 고지방식이 집단에서 낮은 경향을 보였으나 통계적으로 유의하지는 않았다. 이러한 결과는 고지방 식이가 지질독성에 의해 Type-I 근육의 세포괴사를 유도한다는 것을 의미하며, 이는 고지방 섭취가 직접적으로 근 감소증과 관련이 있음을 시사한다.

• Asian-Australasian Journal of Animal Sciences
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• 제31권1호
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• pp.106-115
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• 2018

Objective: The goal of this study was to investigate the effects of dietary standard ileal digestible (SID) valine:lysine ratios on performance, intestinal morphology, amino acids of liver and muscle, plasma indices and mRNA expression of branched-chain amino acid (BCAA) metabolism enzymes. Methods: A total of 144 crossbred pigs (Duroc${\times}$Landrace${\times}$Large White) weaned at $28{\pm}4days$ of age ($8.79{\pm}0.02kg$ body weight) were randomly allotted to 1 of 4 diets formulated to provide SID valine:lysine ratios of 50%, 60%, 70%, or 80%. Each diet was fed to 6 pens of pigs with 6 pigs per pen (3 gilts and 3 barrows) for 28 days. Results: Average daily gain increased quadratically (p<0.05), the villous height of the duodenum, jejunum and ileum increased linearly (p<0.05) as the SID valine:lysine ratio increased. The concentrations of plasma ${\alpha}-keto$ isovaleric and valine increased linearly (p<0.05), plasma aspartate, asparagine and cysteine decreased (p<0.05) as the SID valine:lysine ratio increased. An increase in SID lysine:valine levels increased mRNA expression levels of mitochondrial BCAA transaminase and branched-chain ${\alpha}-keto$ acid dehydrogenase in the longissimus dorsi muscle (p<0.05). Conclusion: Using a quadratic model, a SID valine:lysine ratio of 68% was shown to maximize the growth of weaned pigs which is slightly higher than the level recommended by the National Research Council.

• 한국수산과학회지
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• 제25권3호
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• pp.165-170
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• 1992

1. 우리나라의 강원도 죽변, 경북 영덕, 경남 일광면, 의창군, 충무, 삼천포와 일본의 암수현 대퇴만, 복정현 포저만, 신내천현 횡수하만의 호하대에 서식하는 진주담치를 채집하고, 패각의 내부형태에 관해 조사하였다. 2. 각고에 대한 전폐각근흔 길이의 비율을 조사한 결과 평균치가 가장 큰 것은 경북 영덕산으로 62.47이었으며, 가장 작은 것은 의창산으로 54.17이었다. 이 값은 유럽의 남방종(Mytilus galloprovincialis)의 값 66.06과 유사하며, 유럽 북방종(Mytilus edulis)의 값인 94.79와는 큰 차이가 있음을 알 수 있었다. 3. 각고에 대한 교판길이(hinge plate length)의 비율을 조사한 결과 평균치가 가장 큰 것은 죽변 산으로 61.31이었으며, 가장 작은 것은 일본 대퇴산으로 56.15였다. 이 값은 유럽 남방종(M. galloprovincialis)의 값 59.39와 유사하며, 유럽 북방종(M. edulis)의 값 84.80과는 큰 차이가 있음을 알 수 있었다. 4. 이상의 연구에서 우리나라와 일본 난류역연안에 서식하는 진주담치는 그 패각의 내부형태적 특징에서 지중해 연안, 즉 유럽 남방종인 Mytilus galloprovincialis와 동일한 사실이 판명되었다.

• Reproductive and Developmental Biology
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• 제35권2호
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• pp.151-157
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• 2011

Clinical arthritis is typically divided into rheumatoid arthritis (RA) and osteoarthritis (OA). Arthritis-induced muscle weakness is a major problem in aged people, leading to a disturbance of balance during the gait cycle and frequent falls. The purposes of the present study were to confirm fiber type-dependent expression of muscle atrophy markers induced by arthritis and to identify the relationship between clinical signs and expression of muscle atrophy markers. Mice were divided into four experimental groups as follows: (1) negative control (normal), (2) positive control (CFA+acetic acid), (3) RA group (CFA+acetic acid+type II collagen), and (4) aging-induced OA group. DBQA/1J mice (8 weeks of age) were injected with collagen (50 ${\mu}g/kg$), and physiological (body weight) and pathological (arthritis score and paw thickness) parameters were measured once per week. The gastrocnemius muscle from animals in each group was removed, and the expression of muscle atrophy markers (MAFbx and MuRF1) and myosin heavy chain isoforms were analyzed by reverse transcription-polymerase chain reaction. No significant change in body weight occurred between control groups and collagen-induced RA mice at week 10. However, bovine type II collagen induced a dramatic increase in clinical score or paw thickness at week 10 (p<0.01). Concomitantly, the expression of the muscle atrophy marker MAFbx was upregulated in the RA and OA groups (p<0.01). A dramatic reduction in myosin heavy chain (MHC)-$I{\beta}$ was seen in the gastrocnemius muscles from RA and OA mice, while only a slight decrease in MHC-IIb was seen. These results suggest that muscle atrophy gene expression occurred in a fiber type-specific manner in both RA- and OA-induced mice. The present study suggests evidence regarding why different therapeutic interventions are required between RA and OA.

• 생명과학회지
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• 제33권12호
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• pp.1036-1045
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• 2023

골격근량과 근력의 점진적인 감소를 특징으로 하는 근감소증은 고령화 인구에서 중요한 문제이다. 본 연구는 콩잎 추출물(Soybean Leaf extracts, SL)의 덱사메타손으로 유도된 근위축에 대한 치료적 가능성을 세포 및 동물 모델에서 조사하였다. 세포 실험 결과, SL은 C2C12 근섬유의 형태, 밀도 및 크기가 보존되어 통계적으로 유의미한 수준으로 덱사메타손에 의해 유발된 근위축을 완화하는 것으로 나타났다. 또한, SL 처리는 주요 근육 위축 조절 인자인 muscle RING-finger protein-1 (MuRF1)과 muscle atrophy F-box (MAFbx)의 발현을 mRNA 및 단백질 수준 모두에서 유의하게 하향 조절하였다. 마우스 모델에서 SL 투여는 특히 덱사메타손으로 인한 체중 감소와 근육 소모를 상쇄하여 비복근과 전경골근의 근육량을 보존하는 것으로 나타났다. 기능적으로도 SL을 투여한 마우스는 악력과 트레드밀 지구력이 향상되어 근육 성능이 개선되었다. 또한 SL은 골격근에서 근위축 관련 단백질인 MAFbx의 발현을 억제하여 덱사메타손 유도 근위축에 대한 보호 역할을 보여주었다. 이러한 연구 결과를 종합해 볼 때 SL은 근감소증과 같은 근육 소모 질환을 개선할 수 있는 유망한 천연 치료제가 될 수 있음을 시사한다.

• 대한한의학방제학회지
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• 제29권4호
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• pp.239-252
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• 2021

Objectives : This study is to effect of improving muscle atrophy through water extract on the solid-phase fermentation extraction with Phellinus linteus of discarded Schisandra chinensis in an atorvastatin-induced atrophy C2C12 cell. Methods : C2C12 myoblast were differentiated into myotube by 2% horse serum medium for 6 days, and then treated solid-phase fermentation(S-P) extract at different concentrations for 24h. To investigate the effect of S-P extract on the induction of muscle atrophy and expression of atrophy-related genes and apoptosis in differentiated C2C12 myotubes using a GSH, ROS, real-time PCR, western blots analysis. Results : As a result of treatment with atorvastatin at concentrations of 5, 10, and 20 uM on the 6th day of differentiation in C2C12 myotube cells, it was confirmed that the cell morphology was damaged in a concentration-dependent manner, and the length and thickness of the myotube also decreased in a concentration-dependent manner. Treatment with S-P extract (50, 100 and 200 ㎍/㎖) increased of GSH and inhibited ROS in the atorvastatin-induced muscle atrophy cell model at a concentration that did not induce toxicity. In addition, it was confirmed that it has an effect on muscle reduction by inhibiting apoptosis of muscle cells as well as being involved in protein production and degradation of muscle cells. Conclusions : Atorvastatin-induced atrophy C2C12 cell, S-P extract activates related to differentiation/generation and proteolysis, and inhibits cell death of atrophy in C2C12 cell. Based on this, it is necessary to prove its effectiveness through animal models and human application test, but it is considered to be discarded Schisandra chinensis can present the potential for development as a recycling industrial material.

• The Korean Journal of Physiology and Pharmacology
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• 제6권4호
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• pp.173-181
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• 2002

The sinoatrial (SA) node is a complex and inhomogeneous tissue in terms of cell morphology and electrical activity. There are two models of the cellular organisation of the sinoatrial node: the gradient and mosaic models. According to the gradient model there is a gradual transition in morphology and electrical properties of SA node cells from the centre to the periphery of the SA node. In the mosaic model, there is a variable mix of atrial and sinoatrial node cells from the centre to the periphery. This review focuses on the cellular organisation of the rabbit sinoatrial node in terms of the expression of connexin (Cx40, Cx43 and Cx45), L-type $Ca^{2+}$ channel and $Na^+-Ca^{2+}$ exchanger proteins. These immunocytochemical data, together with morphological and electrophysiological data, obtained from the intact sinoatrial node and isolated sinoatrial node cells support the gradient model of the cellular organisation of the SA node. The complex organisation of the sinoatrial node is important for the normal functioning of the sinoatrial node: (i) it allows the sinoatrial node to drive the surrounding hyperpolarized atrial muscle without being suppressed by it; (ii) it helps the pacemaker activity of the sinoatrial node continue under a wide range of physiological and pathophysiological conditions; (iii) it helps protect the sinoatrial node from reentrant arrhythmias.

• 한국항공운항학회지
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• 제20권3호
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• pp.63-67
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• 2012

Spaceflight induces a number of cardiovascular physiological alterations. To study adaptations to microgravity on Earth, the tail-suspended, hindlimb-unloaded rat model has been used to simulate the effects of microgravity. Despite the extensive use of this model to infer physiological adaptations of many organs to microgravity, little information has been obtained on the effect of tail suspension(TS) on cardiac adaptations in the rat. This study was aimed to investigate the effects of simulated microgravity on the rat myocardium using the TS model. Twenty-four male Sprague-Dawley rats were randomly assigned to 3 experimental groups(1, 7 and 14 days of TS) and a control group. A microscopic examination was performed to assess histopathological changes in the myocardial morphology. The hearts from the control group, the 1 day-TS rats and the 7 day-TS rats revealed no evident abnormalities in cardiomyocyte size and morphology. At day 14 of TS, in contrast, the ventricular cardiomyocytes appeared more separated from each other and were slightly smaller in size compared with those of the control group. Also seen were scattered areas exhibiting focal disorganization of muscle fibers and some degenerating cardiomyocytes, of which the nuclei had become pyknotic or disappeared. In this study, we demonstrated that the ventricular cardiomyocytes underwent degeneration and atrophy at the microscopic level during exposure to simulated microgravity in TS rats.

• 한국동물학회지
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• 제24권4호
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• pp.189-200
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• 1981

12일간 배양한 계배에서 떼어낸 근모세포에 자외선을 조사하면 근육 분화에 심한 변화를 유발시킬수 있다. 본 연구에서는 자외선이 세포분열 및 근섬유로의 전환, 근모세포와 근섬유의 형태에 미치는 영향을 조사하였다. 자외선을 받은 세포들은 크기가 작아지고 또 적은 수의 세포들이 근섬유 형성에 참여하기 때문에 근섬유의 직경이 좁아지고 길이 또한 작아진다. 자외선이 세포분열과 세포의 융합에 미치는 영향은 배양을 시작한 후 이른 시기에 조사할수록 그 효과가 크다. 또한 자외선의 양을 증가시키면 그 효과가 커져 지나친 양을 조사하면 세포에 치사작용을 나타낸다. 따라서 자외선에 의한 세포 밀도의 감소가 근섬유 형성의 저하를 초래하는 것으로 사료되어 이에 본 연구와 타 실험실에서 얻은 정보를 바탕으로 세포 융합 능력 감소의 원인에 대하여 토의하였다.