scholarly journals Aging and acute exercise enhance free radical generation in rat skeletal muscle

1999 ◽  
Vol 87 (1) ◽  
pp. 465-470 ◽  
Author(s):  
J. Bejma ◽  
L. L. Ji
Keyword(s):  
Skeletal Muscle ◽  
Lipid Peroxidation ◽  
Acute Exercise ◽  
Muscle Protein ◽  
Vastus Lateralis ◽  
Age Groups ◽  
Protein Carbonyl ◽  
Biological Aging ◽  
Young Rats ◽  
Old Rats

Reactive oxygen species (ROS) are implicated in the mechanism of biological aging and exercise-induced oxidative damage. The present study examined the effect of an acute bout of exercise on intracellular ROS production, lipid and protein peroxidation, and GSH status in the skeletal muscle of young adult (8 mo, n = 24) and old (24 mo, n = 24) female Fischer 344 rats. Young rats ran on a treadmill at 25 m/min and 5% grade until exhaustion (55.4 ± 2.7 min), whereas old rats ran at 15 m/min and 5% grade until exhaustion (58.0 ± 2.7 min). Rate of dichlorofluorescin (DCFH) oxidation, an indication of ROS and other intracellular oxidants production in the homogenate of deep vastus lateralis, was 77% ( P < 0.01) higher in rested old vs. young rats. Exercise increased DCFH oxidation by 38% ( P < 0.09) and 50% ( P < 0.01) in the young and old rats, respectively. DCFH oxidation in isolated deep vastus lateralis mitochondria with site 1 substrates was elevated by 57% ( P < 0.01) in old vs. young rats but was unaltered with exercise. Significantly higher DCFH oxidation rate was also found in aged-muscle mitochondria ( P < 0.01), but not in homogenates, when ADP, NADPH, and Fe3+ were included in the assay medium without substrates. Lipid peroxidation in muscle measured by malondialdehyde content showed no age effect, but was increased by 20% ( P < 0.05) with exercise in both young and old rats. Muscle protein carbonyl formation was unaffected by either age or exercise. Mitochondrial GSH/ GSSG ratio was significantly higher in aged vs. young rats ( P < 0.05), whereas exercise increased GSSG content and decreased GSH/GSSG in both age groups ( P < 0.05). These data provided direct evidence that oxidant production in skeletal muscle is increased in old age and during prolonged exercise, with both mitochondrial respiratory chain and NADPH oxidase as potential sources. The alterations of muscle lipid peroxidation and mitochondrial GSH status were consistent with these conclusions.

Adaptation to prolonged starvation in the rat: curtailment of skeletal muscle proteolysis

1981 ◽  
Vol 241 (4) ◽  
pp. E321-E327 ◽  
Author(s):  
M. N. Goodman ◽  
M. A. McElaney ◽  
N. B. Ruderman
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Early Event ◽  
Body Protein ◽  
Fed State ◽  
Prolonged Starvation ◽  
Obese Rats ◽  
Old Rats

Previous studies have established that 16-wk-old nonobese and obese rats conserve body protein during prolonged starvation. To determine the basis for this, protein synthesis and degradation in skeletal muscle were evaluated in the isolated perfused hindquarters of these rats, in the fed state and when starved for 2, 5, 10, and 11 days. Rats aged 4 and 8 wk were used as a comparison. The results indicate that the response to starvation depends on several factors: the age of the rat, its degree of adiposity, and the duration of the fast. An early event in starvation was a decline in muscle protein synthesis. This occurred in all groups, albeit this reduction occurred more slowly in the older rats. A later response to starvation was an increase in muscle proteolysis. This occurred between 2 and 5 days in the 8-wk-old rats. In 16-wk-old rats it did not occur until between 5 and 10 days, and it was preceded by a period of decreased proteolysis. In 16-wk-old obese rats, a decrease in proteolysis persisted for upwards of 10 days and the secondary increase was not noted during the period of study. The data suggest that the ability of older and more obese rats to conserve body protein during starvation is due, in part, to a curtailment of muscle proteolysis. This adaptation seems to correlate with the availability of lipid fuels.

Exercise training increases branched-chain oxoacid dehydrogenase kinase content in human skeletal muscle

2007 ◽  
Vol 293 (3) ◽  
pp. R1335-R1341 ◽  
Author(s):  
Krista R. Howarth ◽  
Kirsten A. Burgomaster ◽  
Stuart M. Phillips ◽  
Martin J. Gibala
Keyword(s):  
Skeletal Muscle ◽  
Exercise Training ◽  
Protein Content ◽  
Human Skeletal Muscle ◽  
Acute Exercise ◽  
Citrate Synthase ◽  
Muscle Protein ◽  
Moderate Intensity ◽  
Main Effect ◽  
Branched Chain

The branched-chain oxoacid dehydrogenase complex (BCOAD) is rate determining for the oxidation of branched-chain amino acids (BCAAs) in skeletal muscle. Exercise training blunts the acute exercise-induced activation of BCOAD (BCOADa) in human skeletal muscle (McKenzie S, Phillips SM, Carter SL, Lowther S, Gibala MJ, Tarnopolsky MA. Am J Physiol Endocrinol Metab 278: E580–E587, 2000); however, the mechanism is unknown. We hypothesized that training would increase the muscle protein content of BCOAD kinase, the enzyme responsible for inactivation of BCOAD by phosphorylation. Twenty subjects [23 ± 1 yr; peak oxygen uptake (V̇o2peak) = 41 ± 2 ml·kg−1·min−1] performed 6 wk of either high-intensity interval or continuous moderate-intensity training on a cycle ergometer ( n = 10/group). Before and after training, subjects performed 60 min of cycling at 65% of pretraining V̇o2peak, and needle biopsy samples (vastus lateralis) were obtained before and immediately after exercise. The effect of training was demonstrated by an increased V̇o2peak, increased citrate synthase maximal activity, and reduced muscle glycogenolysis during exercise, with no difference between groups (main effects, P < 0.05). BCOADa was lower after training (main effect, P < 0.05), and this was associated with a ∼30% increase in BCOAD kinase protein content (main effect, P < 0.05). We conclude that the increased protein content of BCOAD kinase may be involved in the mechanism for reduced BCOADa after exercise training in human skeletal muscle. These data also highlight differences in models used to study the regulation of skeletal muscle BCAA metabolism, since exercise training was previously reported to increase BCOADa during exercise and decrease BCOAD kinase content in rats (Fujii H, Shimomura Y, Murakami T, Nakai N, Sato T, Suzuki M, Harris RA. Biochem Mol Biol Int 44: 1211–1216, 1998).

Effects of an acute exercise bout in hypoxia on extracellular vesicle release in healthy and prediabetic subjects

2021 ◽  
Author(s):  
Geoffrey Warnier ◽  
Estelle De Groote ◽  
Florian A. Britto ◽  
Ophélie Delcorte ◽  
Joshua P. Nederveen ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Acute Exercise ◽  
Vastus Lateralis ◽  
Venous Blood ◽  
Plasma Concentrations ◽  
Exercise Bout ◽  
Multivesicular Body ◽  
International Standards ◽  
Size Exclusion ◽  
Number Of Particles

Purpose: To investigate exosome-like vesicle (ELV) plasma concentrations and markers of multivesicular body (MVB) biogenesis in skeletal muscle in response to acute exercise. Methods: Seventeen healthy (BMI: 23.5±0.5kg·m-2) and fifteen prediabetic (BMI: 27.3±1.2kg·m-2) men were randomly assigned to two groups performing an acute cycling bout in normoxia or hypoxia (FiO2 14.0%). Venous blood samples were taken before (T0), during (T30) and after (T60) exercise and biopsies from m. vastus lateralis were collected before and after exercise. Plasma ELVs were isolated by size exclusion chromatography, counted by nanoparticle tracking analysis (NTA), and characterized according to international standards, followed by expression analyses of canonical ELV markers in skeletal muscle. Results: In the healthy normoxic group, the total number of particles in the plasma increased during exercise from T0 to T30 (+313%) followed by a decrease from T30 to T60 (-53%). In the same group, an increase in TSG101, CD81 and HSP60 protein expression was measured after exercise in plasma ELVs; however, in the prediabetic group, the total number of particles in the plasma was not affected by exercise. The mRNA content of TSG101, ALIX and CD9 were upregulated in skeletal muscle after exercise in normoxia; whereas, CD9 and CD81 were downregulated in hypoxia. Conclusions: ELV plasma abundance increased in response to acute aerobic exercise in healthy subjects in normoxia, but not in prediabetic subjects, nor in hypoxia. Skeletal muscle analyses suggested that this tissue did not likely play a major role of the exercise-induced increase in circulating ELVs.

scholarly journals Contractile activity-specific transcriptome response to acute endurance exercise and training in human skeletal muscle

2019 ◽  
Vol 316 (4) ◽  
pp. E605-E614 ◽  
Author(s):  
Daniil V. Popov ◽  
Pavel A. Makhnovskii ◽  
Elena I. Shagimardanova ◽  
Guzel R. Gazizova ◽  
Evgeny A. Lysenko ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Transcription Factors ◽  
Human Skeletal Muscle ◽  
Acute Exercise ◽  
Contractile Activity ◽  
Vastus Lateralis ◽  
Aerobic Exercise Training ◽  
Vastus Lateralis Muscle ◽  
Transcriptome Response ◽  
The One

Reduction in daily activity leads to dramatic metabolic disorders, while regular aerobic exercise training is effective for preventing this problem. The purpose of this study was to identify genes that are directly related to contractile activity in human skeletal muscle, regardless of the level of fitness. Transcriptome changes after the one-legged knee extension exercise in exercised and contralateral nonexercised vastus lateralis muscle of seven men were evaluated by RNA-seq. Transcriptome change at baseline after 2 mo of aerobic training (5/wk, 1 h/day) was evaluated as well. Postexercise changes in the transcriptome of exercised muscle were associated with different factors, including circadian oscillations. To reveal transcriptome response specific for endurance-like contractile activity, differentially expressed genes between exercised and nonexercised muscle were evaluated at 1 and 4 h after the one-legged exercise. The contractile activity-specific transcriptome responses were associated only with an increase in gene expression and were regulated mainly by CREB/ATF/AP1-, MYC/MAX-, and E2F-related transcription factors. Endurance training-induced changes (an increase or decrease) in the transcriptome at baseline were more pronounced than transcriptome responses specific for acute contractile activity. Changes after training were associated with widely different biological processes than those after acute exercise and were regulated by different transcription factors (IRF- and STAT-related factors). In conclusion, adaptation to regular exercise is associated not only with a transient (over several hours) increase in expression of many contractile activity-specific genes, but also with a pronounced change (an increase or decrease) in expression of a large number of genes under baseline conditions.

scholarly journals Lower recovery of muscle protein lost during starvation in old rats despite a stimulation of protein synthesis

1999 ◽  
Vol 277 (4) ◽  
pp. E608-E616 ◽  
Author(s):  
L. Mosoni ◽  
T. Malmezat ◽  
M. C. Valluy ◽  
M. L. Houlier ◽  
D. Attaix ◽  
...  
Keyword(s):  
Gene Expression ◽  
Protein Synthesis ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Age Groups ◽  
Liver Protein ◽  
Protein Mass ◽  
Old Rats ◽  
Proteolytic Pathways ◽  
Lower Recovery

Sarcopenia could result from the inability of an older individual to recover muscle lost during catabolic periods. To test this hypothesis, we compared the capacity of 5-day-refed 12- and 24-mo-old rats to recover muscle mass lost after 10 days without food. We measured gastrocnemius and liver protein synthesis with the flooding-dose method and also measured nitrogen balance, 3-methylhistidine excretion, and the gene expression of components of proteolytic pathways in muscle comparing fed, starved, and refed rats at each age. We show that 24-mo-old rats had an altered capacity to recover muscle proteins. Muscle protein synthesis, inhibited during starvation, returned to control values during refeeding in both age groups. The lower recovery in 24-mo-old rats was related to a lack of inhibition of muscle proteolysis during refeeding. The level of gene expression of components of the proteolytic pathways did not account for the variations in muscle proteolysis at both ages. In conclusion, this study highlights the role of muscle proteolysis in the lower recovery of muscle protein mass lost during catabolic periods.

scholarly journals P0529THE DIFFERENCE IN DIETARY RESTRICTION-INDUCED NEPHROPROTECTIVE MECHANISMS IN YOUNG AND OLD ANIMALS

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Nadezda Andrianova ◽  
Ljubava Zorova ◽  
Irina Pevzner ◽  
Vasily Popkov ◽  
Denis Silachev ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Dietary Restriction ◽  
Kidney Tissue ◽  
Kidney Injury ◽  
Male Rats ◽  
Kidney Cells ◽  
Lipid Peroxidation Products ◽  
Kidney Slices ◽  
Young Rats ◽  
Old Rats

Abstract Background and Aims Acute kidney injury (AKI) is a widespread disease affecting mostly old people. Dietary restriction (DR), based on the reduction of food intake, is believed to be one of the most efficient approaches ameliorating damage in different pathological conditions including age-associated diseases. The aim of the study was to investigate the protective mechanisms of DR in the model of AKI in young and old rats. Method All experiments were made on young (3-4 months) and old (22-24 months) male rats. DR was performed by limiting the amount of food for 35% of the ad libitum (AL) daily intake. Since earlier, we showed ineffectiveness of 4-weeks DR in old rats, in this study we applied 35% DR lasting 8 weeks for old rats and 4 weeks for young rats. During DR, we registered the weight loss and measured the level of adiponectin, as this hormone is closely associated with adipose tissue metabolism. Renal ischemia/reperfusion (I/R) was used as a model of ischemic AKI. I/R was performed by clamping the left renal pedicle for 40 minutes followed by reperfusion with simultaneous contralateral nephrectomy. The severity of AKI was evaluated by measuring blood urea nitrogen (BUN), serum creatinine (SCr) and the levels of protein biomarkers of AKI (NGAL and L-FABP) in urine. Proliferation in kidney epithelium in response to I/R was analyzed by PCNA protein level in kidney tissue. We evaluated the function of mitochondria by measuring TMRE/MitoTracker Green ratio in vital kidney slices; in kidney homogenates, we also analyzed levels of Bcl-XL and Bcl-XS proteins. The production of reactive oxygen species (ROS) was evaluated by staining vital kidney slices with DCF. The content of lipid peroxidation products was measured using Image-iT Lipid Peroxidation Kit, and the level of carbonylated proteins was determined by OxyBlot Protein Oxidation Detection Kit. The activation of autophagic-lysosomal system was estimated by western blotting to LC3 II/LC3 I ratio and LAMP1 level, as well as by staining vital kidney slices with LysoTracker Green probe. Results The body weight of rats during DR dropped as far as 20% by the end of 4 weeks in young rats and 30% by the end of 8 weeks in old rats. Nevertheless, adiponectin concentration elevated during DR only in the serum of young rats. DR strongly influenced mitochondria function, in particular, elevated mitochondrial membrane potential both in kidney cells of young and old rats. DR also resulted in increasing the Bcl-XL level. We revealed the decrease of ROS and lipid peroxidation products in vital kidney slices, but only in kidneys of young rats. However, DR reduced the content of carbonyl groups more than 2 times in animals of both ages. We showed that activation of autophagy in response to DR and I/R occurred only in the kidneys of young rats, indicating deterioration of autophagy signaling in old animals. We also found that 48 h after I/R PCNA level increased 19 times in young kidney, although old rats showed only 4-fold elevation of kidney cells proliferation. Estimation of kidney injury markers (NGAL, L-FABP) in urine revealed that 2-month DR led to some protection in old rats. Nonetheless, despite all positive alterations in kidney tissue of old rats, DR was not able to ameliorate impairment of kidney function after I/R, whereas all young rats showed significant improvement of SCr and BUN levels. Conclusion Short-term DR has a significant nephroprotective effect against renal I/R in young rats. Old animals require longer periods of food restriction, after which some protective alterations are observed. We propose, protection of kidney in old and young rats is implemented through slightly different mechanisms and some of them are missing in old animals.

Subcellular localization-dependent decrements in skeletal muscle glycogen and mitochondria content following short-term disuse in young and old men

2010 ◽  
Vol 299 (6) ◽  
pp. E1053-E1060 ◽  
Author(s):  
Joachim Nielsen ◽  
Charlotte Suetta ◽  
Lars G. Hvid ◽  
Henrik D. Schrøder ◽  
Per Aagaard ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Glycogen ◽  
Vastus Lateralis ◽  
Age Groups ◽  
Quadriceps Muscle ◽  
Fiber Types ◽  
Short Term ◽  
Skeletal Muscle Glycogen ◽  
Before And After ◽  
Old Men

Previous studies have shown that skeletal muscle glycogen and mitochondria are distributed in distinct subcellular localizations, but the role and regulation of these subcellular localizations are unclear. In the present study, we used transmission electron microscopy to investigate the effect of disuse and aging on human skeletal muscle glycogen and mitochondria content in subsarcolemmal (SS), intermyofibrillar (IMF), and intramyofibrillar (intra) localizations. Five young (∼23 yr) and five old (∼66 yr) recreationally active men had their quadriceps muscle immobilized for 2 wk by whole leg casting. Biopsies were obtained from m. vastus lateralis before and after the immobilization period. Immobilization induced a decrement of intra glycogen content by 54% ( P < 0.001) in both age groups and in two ultrastructurally distinct fiber types, whereas the content of IMF and SS glycogen remained unchanged. A localization-dependent decrease ( P = 0.03) in mitochondria content following immobilization was found in both age groups, where SS mitochondria decreased by 33% ( P = 0.02), superficial IMF mitochondria decreased by 20% ( P = 0.05), and central IMF mitochondria remained unchanged. In conclusion, our findings demonstrate a localization-dependent adaptation to immobilization in glycogen and mitochondria content of skeletal muscles of both young and old individuals. Specifically, this suggests that short-term disuse preferentially affects glycogen particles located inside the myofibrils and that mitochondria volume plasticity can be dependent on the distance to the fiber border.

scholarly journals Myosin heavy chain expression in rodent skeletal muscle: effects of exposure to zero gravity

1993 ◽  
Vol 75 (6) ◽  
pp. 2471-2477 ◽  
Author(s):  
F. Haddad ◽  
R. E. Herrick ◽  
G. R. Adams ◽  
K. M. Baldwin
Keyword(s):  
Skeletal Muscle ◽  
Muscle Protein ◽  
Vastus Lateralis ◽  
Mrna Level ◽  
Relative Content ◽  
Type I ◽  
Zero Gravity ◽  
Mrna Levels ◽  
Heavy Chains ◽  
Vastus Intermedius

This study ascertained the effects of 9 days of zero gravity on the relative (percentage of total) and calculated absolute (mg/muscle) content of isomyosin expressed in both antigravity and locomotor skeletal muscle of ground control (CON) and flight-exposed (FL) rats. Results showed that although there were no differences in body weight between FL and CON animals, a significant reduction in muscle mass occurred in the vastus intermedius (VI) (P < 0.05) but not in the vastus lateralis (VL) or the tibialis anterior. Both total muscle protein and myofibril protein content were not different between the muscle regions examined in the FL and CON groups. In the VI, there were trends for reductions in the relative content of type I and IIa myosin heavy chains (MHCs) that were offset by increases in the relative content of both type IIb and possibly type IIx MHC protein (P > 0.05). mRNA levels were consistent with this pattern (P < 0.05). The same pattern held true for the red region of the VL as examined at both the protein and mRNA level (P < 0.05). When the atrophy process was examined, there were net reductions in the absolute content of both type I and IIa MHCs that were offset by calculated increases in type IIb MHC in both VI and red VL. Collectively, these findings suggest that there are both absolute and relative changes occurring in MHC expression in the "red" regions of antigravity skeletal muscle during exposure to zero gravity that could affect muscle function.

Dysregulation of hepatic iron with aging: implications for heat stress-induced oxidative liver injury

2008 ◽  
Vol 294 (4) ◽  
pp. R1165-R1174 ◽  
Author(s):  
Steven A. Bloomer ◽  
Kyle E. Brown ◽  
Garry R. Buettner ◽  
Kevin C. Kregel
Keyword(s):  
Lipid Peroxidation ◽  
Heat Stress ◽  
Liver Injury ◽  
Iron Content ◽  
Nonheme Iron ◽  
Hepatic Iron ◽  
Young Rats ◽  
Age Related ◽  
Old Rats ◽  
Labile Iron

Environmental heat stress is associated with an age-related increase in hepatic oxidative damage and an exaggerated state of oxidative stress. The purpose of this investigation was to evaluate the regulation of hepatic iron after heat stress. A secondary aim was to determine a potential role for iron in heat stress-induced liver injury. Hyperthermia-induced alterations in hepatic iron were evaluated in young (6 mo) and old (24 mo) Fischer 344 rats by exposing them to a two-heat stress protocol. Livers were harvested at several time points after the second heating and assayed for labile and nonheme iron. In the control condition, there was no difference in labile iron between age groups. Both labile iron and storage iron were not altered by hyperthermia in young rats, but both were increased immediately after heating in old rats. To evaluate a role for iron in liver injury, hepatic iron content was manipulated in young and old rats, and then both groups were exposed to heat stress. Iron administration to young rats significantly increased hepatic iron content and ferritin but did not affect markers of lipid peroxidation under control conditions or after heat stress. In old rats, iron chelation with deferoxamine prevented the increase in nonheme iron, labile iron, ferritin, and lipid peroxidation after heat stress. These results suggest that iron may play a role in hepatic injury after hyperthermia. Thus, dysregulation of iron may contribute to the gradual decline in cellular and physiological function that occurs with aging.

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