ABSTRACT
The purpose of this study was to examine the effects of combination of a heat stress and astaxanthin supplementation, known as a potent anti-oxidative nutrient, on muscle protein degradation and disuse muscle atrophy. Fifty-two male Wistar rats (261.7±1.17 g) were divided into five groups: control (Cont, n=10), suspension (Sus, n=11), heat stress and suspension (Heat, n=10), astaxanthin and suspension (Ax, n=10), and heat stress, astaxanthin and suspension (H+A, n=11). There were no significant differences in Cu,Zn-SOD, cathepsin L and caspase-3 levels among the Heat, Ax and H+A groups in the soleus and plantaris muscles. Although levels of calpain 2 and ubiquitinated protein in the myofibrillar fraction in the soleus muscle were not significantly different among the Heat, Ax and H+A groups, levels in the H+A group were significantly (p<0.05) lower than Sus. Concerning atrophied plantaris muscles, the H+A group significantly (p<0.05) suppressed the expression of calpain 1 in the myofibrillar fraction, but there were no marked changes of proteolytic indexes. These data indicate that the combination of the heat stress and astaxanthin supplementation could be effective in inhibiting muscle protein degradation in disuse atrophy of the soleus.
ABSTRACT
In the present study, we investigated the effect of heat stress on disuse atrophy from changes in the muscle protein levels of desmin and calpain. Wistar strain female rats (6-8 months old) were randomly assigned to two experimental groups: control (C) and heat stress (H). One hindlimb of all animals was immobilized in plantar flexion with plaster. Before immobilization, animals in H group were placed in a heat chamber (42°C for 60 min). Following 6 days of immobilization, the soleus muscles were removed and analyzed. Although immobilization resulted in significant muscle atrophy in all experimental animals, the soleus weight-to-body weight ratio in immobilized limbs of H group was significantly higher compared to that of C group. Expression of desmin and HSP72 in the atrophied soleus muscle from C group was significantly lower compared with the contralateral muscle; but this was not the case in H group. Further, in C group, the ratio of autolyzed calpains I increased significantly in the atrophied muscle compared to the contralateral muscle. These results show that the effect of heat stress on disuse skeletal muscle atrophy is attributed to the decreasing degradation of desmin by suppressing the activation of calpain.
ABSTRACT
Oxidative stress is thought to be a significant contributing factor of age-related sarcopenia. We tested the hypothesis that long-term dietary antioxidant (astaxanthin) intake attenuates sarcopenia. Wistar strain male rats, aged 45 weeks old, were given either control (Cont) or astaxanthin feed (0.004%, Ax) for 1 year. The soleus muscle weight and muscle weight-to-body weight ratios in Ax group were significantly higher than in Cont group, but tibialis anterior muscle mass was similar between the two dietary groups. The level of ubiquitinated proteins was significantly lower in the soleus muscles of Ax group, but not in tibialis anterior muscles when compared with Cont group. Tibialis anterior levels of cathepsin L, especially, and caspase-3 tended to be lower in Ax group than in Cont group. Cathepsin L levels were significantly lower. Whereas no differences between Cont and Ax were observed in soleus levels. There were no significant differences in Ax supplementation on calpain 1 and 2, UBC3B, Cu/Zn SOD and nitrotyrosine levels in either soleus or tibialis anterior muscles. Our data suggest that long-term dietary astaxanthin intake attenuates age-related muscle atrophy, due in part, to reduction in ubiquitination of myofibrillar protein in slow soleus muscles, but not in fast tibialis anterior muscles.
ABSTRACT
It has been demonstrated that exercise induces heat shock proteins (HSPs) . However, no study has investigated changes in HSPs following endurance training at different speeds. Therefore, this study was designed to investigate the effect of treadmill training at different running speeds on induction HSPs. One group of male Wistar rats was assigned as a sedentary control, three groups were assigned for exercise training (10 m/min, 20 m/min and 30 m/min) and another three groups for one acute bout of exercise (10 m/min, 20 m/min and 30 m/min) . Each training group ran at each speed for 30 min/day, 5 days a week for 8 weeks. The acute exercise group performed the exercise only once. Forty-eight hours after the last exercise session was completed, the rats were sacrificed and the plantaris (PLA) and soleus (SOL) muscles were dissected. In the acute exercise group, the content of HSP72 in both the PLA and SQL increased (p<0.05) at all speeds, and the content of HSP60 increased significantly (p<0.05) at all speeds for the PLA, but not for the SOL. On the other hand, in the endurance group, the content of HSP72 and HSP60 in both muscles increased in 30 m/min groups. These results indicate that an increase in HSP72 and HSP60 by endurance training is induced by high intensity training in both muscles. This was not found to be the case with the acute exercise groups.
ABSTRACT
The circadian rhythm of heart rate is well known. The purpose of this study was to investigate the characteristics of the relation between heart rate and oxygen uptake during a graded exercise testing with and without previous exercise. Eight healthy male students, aged 18 to 21 years, performed the graded sub-maximal exercise two times using a treadmill, after walking on a treadmill at a speed of 60 m/min for a total of 4 hours (2 hours in the morning, 2 hours in the afternoon) and without previous prolonged walking. The apparent resting heart rate after one hour of walking in the afternoon (82.3±9.1 beats mm) was higher than in the morning (71.3±5.8 beats/min), and this phenomenon was observed continuously exercise heart rate at the end of 2 hours of walking (afternoon : 96.4±5.4, morning: 87.2±7.3 beats min) . On the other hand, the oxygen uptake during exercise did not alter at the end of walking (afternoon: 622±85, morning: 600±133 ml/min) . This walking intensity ranged from 17.1 to 26.6, with a mean of 20.5 percent of maximal oxygen uptake. The pre-exercise resting heart rate before the exercise testing altered from -4.8 to 13.1 beats/min with and without the presence of walking. The observed individual regression line between heart rate and oxygen uptake from the testing shifted along with the altered resting heart rate. Therefore, the calculated individual new regression lines with and without walking between net heart rate, excluding pre-exercise rest, and oxygen uptake were approximate to a constant line. It was concluded that the exercise energy expenditure could be calculated accurately (-2 to 7 % of errors) using net heart rate, as compared with overestimations of the actual energy cost using the higher resting heart rate.
ABSTRACT
The effects of testosterone on the structural and contractile properties of the denervated rat skeletal muscles that were not influenced by neurotrophic-effects were investigated. Male Wistar strain rats (3-week-old, n=28) were used in the present study. All rats were divided into four (n=7, for each) groups; control (C), testosterone control (TC), denervated (DN), and denervated with testosterone (DNT) groups. Sciatic nerves of DN and DNT groups' rats were resected at the 4-week-old after birth. Testosterone that was melted in corn-oil was administered (40 mg/kg body weight/week) for the TC and DNT groups. At the end of breeding period (15-week-old), soleus (SOL) and extensor digitorum longus (EDL) muscles were dissected from both hindlimbs and contractile profiles were analyzed in vitro. Relative weight (muscle weight/body weight) of SOL muscle in the DNT group was significantly (p<0.01) higher than that of the DN group. There is no significant difference in EDL muscle between the DN and DNT groups. Time to peak tension and half relaxation time in EDL muscle of the DNT group was significantly (p<0.05) higher than those of the DN group. Maximum twitch tension was prone to decrease following denervation, and significantly (p<0.01) difference between the DN and DNT groups in both muscles regarding the maximum twitch tension was observed. There is no significant difference of myosin and actomyosin ATPase activities comparison of each group in SOL muscle, however, the TC group were significantly higher than those of the C group in EDL muscle. These results suggested that the effects of testosterone for the hypertrophy in skeletal muscles were not synergistic effects with the neurotrophiceffects, however, for the ATPase in fast muscle act synergistically with the neurotrophic effect to change of myosin ATPase. Moreover, it was also suggested that the sensitivity to the testosterone was different in each type of fiber.
ABSTRACT
The effect of swimming training on creatine ki nase (CK) isoenzyme compositions (cytoplasmic CK : CK-MM, -MB, -BB ; mitochondrial CK : m-CK) of coleus (SOL), extensor digitorum longus (EDL) and heart muscles were studied. Wistar strain male rats were trained by swimming at a water temperature of 38±2°C, loaded with a weight equal to 5% of their body weight attached to their tails, and made to swim 4-days per week from the age of 4 weeks old for 4, 6 and 8 weeks. CK isoenzyme compositions of SOL, EDL and heart were different from those of other muscles. The activities of CK-MB and m-CK of SOL, EDL and heart increased following exercise training. CK isoenzyme composition of skeletal muscle (SOL and EDL) tended to qualitatively resemble the heart with training. These results suggest that the training-induced metabolic change in skeletal muscle causes similar CK isoenzyme composition to the heart muscle, and ensure energy production for the continuous muscle contraction during endurance exercise. The possibility that the source of the increased serum CK-MB activity after exercise is from the skeletal muscle should be examined thoroughly when the high serum CK-MB activity is interpreted.
ABSTRACT
The effects of different types of running trainings (sprint or endurance) on the glycolytic (lactate dehydrogenase : LDH, phosphofructokinase : PFK and pyruvate kinase : PK) and oxidative (succinate dehydrogenase : SDH and malate dehydrogenase : MDH) enzymes activities and on the mitochondrial contents in single muscle fiber of different types (slow-twitch oxidative : SO, fast-twitch oxidative glycolytic : FOG and fast-twitch glycolytic : FG) were studied employing biochemical and electron microscopic techniques. Male Wistar strain rats were trained by treadmill 5 days/week beginning the age of 3 weeks old for 16 weeks. Single muscle fibers were dissected from soleus and extensor digitorum longus muscles, and typed histochemically into SO, FOG and FG fibers. The remaining parts of the single muscle fiber were used for biochemical and electron microscopic analyses. Glycolytic enzymes activities were increased in FG and FOG fibers following sprint training. Oxidative enzymes activities were increased in all types of fiber following both trainings. Mitochondrial contents in single muscle fiber were increased in FOG fiber following sprint training and in SO fiber following endurance training. These results suggest that the increase of glycolytic enzymes activity following sprint training were depended on the the fast-type fiber specifically and that of oxidative enzymes activity were depended on all types of fiber in whole muscle. It seems that the increase of oxidative enzymes activity following exercise training alone was not only depended on the increase of mitochondrial contents in skeletal muscle fiber.
ABSTRACT
Fifty-two trained athletes (15 short-distance runners, 20 long-distance runners, and 17 jumpers) and 5 controls were examined for leg length discrepancy, pelvic obliquity, scoliosis, leg strength discrepancy, and leg injury. Forty-seven subjects (90%) in the trained group and 4 subjects (80%) in the control group had leg length discrepancies. Differences of the femur lengths and tibia lengths, not of the joint space or soft tissue, were main factors of leg length discrepancies. There were no significant differences in leg length discrepancy and in pelvic obliquity between the trained and control groups. The trained group had twice as many leg length discrepancies and pelvic obliquities as the control group in average. A positive correlation between leg length discrepancy and pelvic obliquity was noted (p<0.001) . Among the jumpers, those who had suffered from hamstring muscle strain showed significantly more discrepancies in the right and left knee flexion strengths than the jumpers who had never experienced such muscle strain (p<0.41) . The rate of knee flexion strength against extension strength was significantly lower in the jumpers who had experienced knee joint injuries (p<0.01) .<BR>The results indicate that leg length discrepancy affects on the pelvic obliquity and scoliosis. Differences of the femur lengths and tibia lengths were main factors of length discrepancy. It is possible that an inequality of load on the right and left legs may cause leg length discrepancy.
ABSTRACT
Five long-distance runners and five non-athletes were examined on lipoprotein metabolism at rest, during, and after pedaling exercise (60% of the maximal oxygen uptake) . At rest, the concentrations of the cholesterol (Cho.), triglyceride (TG), and phospholipid (PL) of very low density lipoprotein (VLDL) were kept at low level in the longdistance group compared with the non-athletes. The difference is significant (p<0.01) . On the other hand, the levels of the Cho, and PL of high density lipoprotein (HDL) were maintained high (p<0.05) . The concentrations of the TG of VLDL are in negative correlation with those of the Cho. (p<0.01) and PL (p<0.001) of HDL at rest. A positive correlation between Cho. and PL of HDL was also noted (p<0.001) . The TG of the VLDL decreased gradually with pedaling exercise in the long-distance group, reaching about 12 percent below the resting value just after exercise. However, no apparent change was noted in the non-athletes.<BR>The results obtained indicate that the long-distance runners, compared with nonathletes, tends to use lipids in order to produce energy for exercise. There is little possibility of transferring from the Cho. and PL of VLDL to the lipoprotein during exercise for the results of no change in concentrations of the Cho. and PL of low density lipoprotein (LDL) and HDL. We concluded that the Cho, and PL of VLDL could gradually transfer to HDL by a heap of the endurance exercise for long period.
ABSTRACT
In this study, the rats were subjected to a partial denervation of the soleus muscle at the age of three weeks. After this, histochemical investigations were carried out to establish what kind of changes had occurred in the differentiation of the muscle fiber type as a result of this partial drop in muscle activity.<BR>The partial denervation was performed on the sinistral rat's soleus muscle, roughly 20% of the nerve bundles. After this, the dextral soleus muscle was used as the contralateral control muscle and excised after two, four and eight weeks, respectively. Frozen sections of muscle were stained with HE and myosin ATPase. The cross sectioned specimen were used for determining the muscle fiber count and type II fiber count.<BR>The results thus obtained show that, compared with the contralateral control muscle, the partially denervated muscle have an approximately 5% reduced muscle fiber count two and four weeks after the partial denervation, and the type II fiber count, too, decreased to approximately 2/3 and 1/5, respectively. However, at eight weeks post-operatively, the muscle fiber count for the partially denervated muscle become almost the same as that for the contralateral control muscle, while the type II fiber count has, at this stage, recovered to approximately half its contralateral control muscle.<BR>From these observations, it had been concluded that the reduction in muscle activity due to its partial denervation continues to act as a causal factor in the fiber type transformation untill four weeks after the partial denervation. The muscles evaluted eight weeks postoperatively showed an increase in type II fiber over the count determined four weeks after the partial denervation, and the muscle fiber count had also developed at eight weeks to value identical to that of the contralateral control muscles. Therefore, it has been concluded that the fiber type transformation in the muscle eight weeks after partial denervation is attributable to the reinnervation of the denervated muscle fibers due to the remaining intact motoneurons and to the resulting changes in motor unit size.
ABSTRACT
At early stage of rats after birth, each innervation muscle fiber is supplied by two or more motor axones which converge on to a single end-plate and become one single axon in future. And undifferentiated cells frequently observed in the interspace among muscle fibers. About 70% of number of total muscle fibers in soleus developed in 21st day after birth.<BR>Effect of denervation on the process of muscle development is studied in this paper. Left saiatic nerve of the rats was cut at 1st, 7th, 14th, and 21st day after birth. After 2 and 4 weeks, soleus and extensor digitorum longus muscle of both legs were dissected. Right side muscles used as control. Each muscle was cut transversely at the muscle belly and quickly frozen. Frozen sections, about 10 pm thick, were stained with hematoxylin eosin and other histochemical agents. Many optical micrographs of 50 or 100 magnifications were obtained from one cross-sectioned specimen. Number of muscle fibers were calculated on combined micrographs.<BR>The results were as follows : (1) At 2 and 4 weeks after denervation, percentage loss of muscle weight was always higher than the loss of muscle cross-sectional area. At 2 and 4 weeks after denervation, the muscle weights were reduced to 45-80% and 70-90% of the control. And denervation muscle weights highly reduced in order that of let, 7th, , 14th and 21st eray rate after birth (2) At 2 and 4 weeks after denervation, number of soleus muscle fibers were reduced to 20-50% and 50-70% of the control. (3) At 2 weeks after denervation the reduction of number of muscle fibers of 1st day old rats was smaller than that of 7 days old rats.<BR>First and second results suggest that muscle development is certainly influenced by neurotrophic foctors. But from third result it is possible to think that muscle development at 1st day old rats is influenced by inheritfactors of the muscle.
ABSTRACT
It is significant for whole body training of endurance ability or exerise as rehabilitation treatment of various diseases, that a fixed quantity of exercise in response to a defined level of heart rate could be loaded voluntarily.<BR>In the present studies it was determined heart rate, respiration rate, number of steps, treadmill speed, moreover, relationship between treadmill speed and heart rate, sudden change of exercise strength on intentional fixed quantity exercise in response to previously defined level of heart rate could be loaded by treadmill connected with “Heart Rate Controller (Quinton Co., Ltd.) ”.<BR>A series of patterns in treadmill running of the normal adult males were analyzed.<BR>On the other hand, transition of blood chemical substances during above exercise at defined heart rate were determined by use of the SMAC-System autoanalyzed (Technicon Co., Ltd.) .<BR>The obtained results in the follows;<BR>1) The relation between treadmill speed and heart rate defined at 130 beats/min, 150 or 170 each, are as follows.<BR>a) Treadmill speed at heart rate, previously defined as 130 b/min was 80±5-12 meters/min, actual heart rate during above exercise was 130±3-8 b/min in record.<BR>b) Treadmill speed at heart rate, 150 b/min was 100 ±9-18 m/min, actual heart rate 150±6-8 b/min in record.<BR>c) Treadmill speed at heart rate, 170 b/min was 130±10-33 m/min, actual heart rate 170±3-9 b/min in record.<BR>2) In the present studies respiratory rate during exercise at defined heart rate level neither altered nor had relation with treadmill speed. The number of steps did not alter, rather appeared to determine respiratory rate.<BR>3) When sudden change of exercise strength during exercise at defined heart rate level appeared, for instances, treadmill speed got quicker, deviated raise of rate from defined heart rate level varied by the individuals and also load on heart itself did by the individuals.<BR>4) In determination of blood chemical substances during exercise at defined 150 b/min or 170 b/min of heart rate level by SMAC-System, transition of above substances were observed to be within normal range but thier levels before exercise were promptly restored.<BR>From the results mentioned above it is suggested that process of intermediated metabolism during above exercise could be considerably stable and exercise load at a defined heart rate level can be prescribed intentionally.
ABSTRACT
In the present studies it was examined to begin with, whether intentional fixed quantity of exercise in response to previously defined level of heart rate could be loaded by treadmill connected with“Heart Rate Controller” (Quinton Co., Ltd.) i.e. a series of patterns in running exercise of the normal adult males were analysed.<BR>The obtained results in short are in the following ;<BR>1) Running exercise in response to previously defined level of heart rate being carried out by use of the above“Heart Rate Controler”, speed of treadmill needed to be adjusted manually until heart rate reached the defined level and then controlled automatically.<BR>2) The relations between treadmill speed and heart rate defined at 130 Beats/min, 150 or 170 each, are as follows.<BR>a) Treadmill speed at heart rate, previously defined as 130 B/min was 80±5-12 meters/min, actual heart rate during above exercise was 130±3-8 B/min in record.<BR>b) Treadmill speed at heart rate, 150 B/min was 100±9-18 m/min, actual heart rate 150±6-8 B/min in record.<BR>c) Treadmill speed at heart rate, 170 B/min was 130±10-33 m/min, actual heart rate 170±3-9 B/min in record.<BR>As previously defined heart rate level was indreased, actual level in record deviated from the former within some extent and treadmill speed was also raised to maintain the defined heart rate level.<BR>Fluctuation width of treadmill speed varied remarkably by the individuals.<BR>Adjustment of treadmill speed was considered to be well under control by feedback mechanism of“Heart Rate Controller”.