Effects of body temperature during exercise training on myocardial adaptations

2001 ◽  
Vol 280 (5) ◽  
pp. H2271-H2280 ◽  
Author(s):  
M. Brennan Harris ◽  
Joseph W. Starnes

This study determined the role of body temperature during chronic exercise on myocardial stress proteins and antioxidant enzymes as well as functional recovery after an ischemic insult. Male Sprague-Dawley rats were exercised for 3, 6, or 9 wk in a 23°C room (3WK, 6WK, and 9WK, respectively) or in a 4–8°C environment with wetted fur (3WKC, 6WKC, and 9WKC, respectively). The colder room prevented elevations in core temperature. During weeks 3–9 the animals ran 5 days/wk up a 6% grade at 20 m/min for 60 min. Myocardial heat shock protein 70 (HSP 70) increased 12.3-fold ( P < 0.05) in 9WK versus sedentary (SED) rats but was unchanged in the cold-room runners. Compared with SED rats, αB-crystallin was 90% higher in 9WKC animals, HSP 90 was 50% higher in 3WKC and 6WKC animals, and catalase was 23% higher in 3WK animals ( P < 0.05 for all). Cytosolic superoxide dismutase increased and mitochondrial SOD decreased ( P < 0.05) in 3WK and 6WK rats compared with 3WKC and 6WKC rats. Antioxidant enzymes returned to SED values in all runners by 9 wk. No differences were observed among any of the groups for glucose-regulated protein 75, heme oxygenase-1, or glutathione peroxidase. Mechanical recovery of isolated working hearts after 22.5 min of global ischemia was enhanced in 9WK ( P < 0.05) but not in 9WKC rats. We conclude that exercise training results in dynamic changes in cardioprotective proteins over time which are influenced by core temperature. In addition, cardioprotection resulting from chronic exercise appears to be due to increased HSP 70.

2009 ◽  
Vol 10 (4) ◽  
pp. 374-380 ◽  
Author(s):  
Pamela Johnson Rowsey ◽  
Bonnie L. Metzger ◽  
John Carlson ◽  
Christopher J. Gordon

Long-term exercise training selectively alters serum cytokines involved in fever. Chronic exercise training has a number of effects on the immune system that may mimic the physiological response to fever. Female rats that voluntarily exercise on running wheels develop an elevated daytime core temperature after several weeks of training. It remains to be seen whether the elevation in daytime temperature involves inflammatory patterns characteristic of an infectious fever. We assessed whether chronic exercise training in the rat would alter levels of cytokines involved in fever. Female Sprague Dawley rats at 45 days of age weighing 90—110 g were divided into two groups (exercise and sedentary) and housed at an ambient temperature of 22°C. Interleukin-1 beta (IL-1β), interleukin-6 (IL-6), interleukin-10 (IL-10), tumor necrosis factor alpha (TNF-α), iron, and zinc levels were analyzed. Rats underwent 8 weeks of exercise on running wheels. Exercise led to altered levels of some key cytokines that are involved in fever. Exercise animals had significantly higher IL-1β levels and lower IL-10 levels compared to sedentary animals. Although IL-6 levels were slightly lower in the exercise animals, these levels were not significantly affected by training. TNF-α activity was similar in the two groups. Training also led to a slight increase in serum zinc and decrease in serum unsaturated iron binding capacity (UIBC). The data suggest that chronic exercise training evokes immune responses that mimic some, but not all, aspects of fever. This may explain why exercise leads to elevated daytime core temperature.


1999 ◽  
Vol 86 (5) ◽  
pp. 1696-1701 ◽  
Author(s):  
Earl G. Noble ◽  
Albert Moraska ◽  
Robert S. Mazzeo ◽  
David A. Roth ◽  
M. Charlotte Olsson ◽  
...  

High-intensity treadmill exercise increases the expression of a cardioprotective, inducible 72-kDa stress protein (SP72) in cardiac muscle. This investigation examined whether voluntary free wheel exercise training would be sufficient to confer a similar response. Male Sprague-Dawley rats were randomly assigned to either treadmill (TM-Tr) or free wheel (FW-Tr) training groups. By the end of the 8-wk training period, TM-Tr animals ran 1 h/day, 5 days/wk up a 10% grade, covering a distance of 8,282 m/wk. FW-Tr rats ran, on average, 5,300 m/wk, with one-third of the animals covering distances similar to those for the TM-Tr group. At the time of death, hearts of trained and caged sedentary control (Sed) animals were divided into left (LV) and right (RV) ventricles. Citrate synthase activity and the relative immunoblot contents of SP72, SP73 (the constitutive isoform of the SP70 family), and a 75-kDa mitochondrial chaperone (SP75) were subsequently determined. LV and RV did not differ on any measure, and SP73, SP75, and citrate synthase were not affected by training. Cardiac SP72 levels were elevated over fourfold in both ventricles of TM-Tr compared with RV of FW-Sed rats. Despite the animals having run a similar total distance, cardiac SP72 content in FW-Tr rats was not different from that in Sed animals. These data indicate that voluntary exercise training is insufficient to elicit an elevation of SP72 in rat heart and suggest that exercise intensity may be a critical factor in evoking the cardioprotective SP72 response.


2006 ◽  
Vol 291 (6) ◽  
pp. R1756-R1763 ◽  
Author(s):  
John M. Lawler ◽  
Hyo-Bum Kwak ◽  
Wook Song ◽  
Janet L. Parker

Oxidative stress is associated with muscle fatigue and weakness in skeletal muscle of ischemic heart disease patients. Recently, it was found that endurance training elevates protective heat shock proteins (HSPs) and antioxidant enzymes in skeletal muscle in healthy subjects and antioxidant enzymes in heart failure patients. However, it is unknown whether coronary ischemia and mild infarct without heart failure contributes to impairment of stress proteins and whether exercise training reverses those effects. We tested the hypothesis that exercise training would reverse alterations in muscle TNF-α, oxidative stress, HSP70, SOD (Mn-SOD, Cu,Zn-SOD), glutathione peroxidase (GPX), and catalase (CAT) due to chronic coronary occlusion of the left circumflex (CCO). Yucatan swine were divided into three groups ( n = 6 each): sedentary with CCO (SCO); 12 wk of treadmill exercise training following CCO (ECO); and sham surgery controls (sham). Forelimb muscle mass-to-body mass ratio decreased by 27% with SCO but recovered with ECO. Exercise training reduced muscle TNF-α and oxidative stress (4-hydroxynonenal adducts) caused by CCO. HSP70 levels decreased with CCO (−45%), but were higher with exercise training (+348%). Mn-SOD activity, Mn-SOD protein expression, and Cu,Zn-SOD activity levels were higher in ECO than SCO by 72, 82, and 112%, respectively. GPX activity was 177% greater in ECO than in SCO. CAT trended higher ( P = 0.059) in ECO compared with SCO. These data indicate that exercise training following onset of coronary artery occlusion results in recovery of critical stress proteins and reduces oxidative stress.


2021 ◽  
Vol 5 (Supplement_2) ◽  
pp. 347-347
Author(s):  
Maureen Meister ◽  
Rami Najjar ◽  
Jessica Danh ◽  
Lena MT Lear ◽  
Justina Kim ◽  
...  

Abstract Objectives To determine whether a diet supplemented with red raspberry (RB) is effective at reducing angiotensin (Ang) II-induced oxidative stress in the lungs of Sprague Dawley (SD) rats. Methods Eight-week-old male SD rats were fed an AIN-93M diet alone (control and Ang II) or supplemented with 10% w/w freeze-dried RB powder for a total of seven weeks. At week 4, SD rats were implanted with subcutaneous osmotic minipumps for delivery of 0.9% saline (control) or Ang II (270 ng/kg body weight/day). Following 3 weeks of infusion, rats were sacrificed, and lungs were collected for analysis. Protein expression of the pro-oxidant enzyme, NADPH oxidase (NOX) 4, and antioxidant enzymes superoxide dismutase 1 (SOD1), catalase, heme oxygenase-1 (HO-1), and NADPH quinone dehydrogenase 1 (NQO1) were assessed by western blot. Results were analyzed by one-way ANOVA followed by Tukey post-hoc test. Results were normalized to control and presented as means ± standard deviation. Results RB supplementation significantly increased the expression of antioxidant enzymes, including, SOD1 (1.34 ± 0.16, n = 5, vs 1.11 ± 0.13-fold, n = 5, P = 0.04) and catalase (1.50 ± 0.28, n = 5, vs 0.79 ± 0.20-fold, n = 5, P = 0.008), when compared to Ang II alone. Compared to control, however, RB significantly increased SOD1 (1.00 ± 0.05-fold, n = 4, P = 0.004) while catalase did not (1.00 ± 0.40, n = 4, P = 0.07). Similarly, HO-1 (1.66 ± 0.82, n = 5, vs 0.75 ± 0.13-fold, n = 4, P = 0.046) and NQO1 (2.13 ± 0.19, n = 4, vs 1.26 ± 0.14-fold, n = 5, P &lt; 0.0001) were greater in the RB supplemented rats in comparison to Ang II alone. Additionally, RB significantly increased NQO1 (1.00 ± 0.16, n = 4, P &lt; 0.0001) but not HO-1 (1.00 ± 0.43-fold, n = 4, P = 0.22) when compared to control. RB supplementation also decreased the expression of NOX4 (0.77 ± 0.38, n = 5, vs 1.41 ± 0.30-fold, n = 5, P = 0.02) in comparison to Ang II alone. Conclusions Our results suggest the potential for red raspberries to decrease oxidative stress within the lung tissue. As investigations into whole food dietary treatments in lung conditions are essentially non-existent, future work will aim to determine the potential for raspberries to serve as a complementary therapy in these conditions. Funding Sources This work was funded by the Agriculture and Food Research Initiative (grant no. 2019–67,017-29,257/project accession no. 1,018,642) from the USDA National Institute of Food and Agriculture.


1990 ◽  
Vol 68 (6) ◽  
pp. 2337-2343 ◽  
Author(s):  
M. H. Laughlin ◽  
T. Simpson ◽  
W. L. Sexton ◽  
O. R. Brown ◽  
J. K. Smith ◽  
...  

The purposes of this study were to determine whether exercise training induces increases in skeletal muscle antioxidant enzymes and to further characterize the relationship between oxidative capacity and antioxidant enzyme levels in skeletal muscle. Male Sprague-Dawley rats were exercise trained (ET) on a treadmill 2 h/day at 32 m/min (8% incline) 5 days/wk or were cage confined (sedentary control, S) for 12 wk. In both S and ET rats, catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPX) activities were directly correlated with the percentages of oxidative fibers in the six skeletal muscle samples studied. Muscles of ET rats had increased oxidative capacity and increased GPX activity compared with the same muscles of S rats. However, SOD activities were not different between ET and S rats, but CAT activities were lower in skeletal muscles of ET rats than in S rats. Exposure to 60 min of ischemia and 60 min of reperfusion (I/R) resulted in decreased GPX and increased CAT activities but had little or no effect on SOD activities in muscles from both S and ET rats. The I/R-induced increase in CAT activity was greater in muscles of ET than in muscles of S rats. Xanthine oxidase (XO), xanthine dehydrogenase (XD), and XO + XD activities after I/R were not related to muscle oxidative capacity and were similar in muscles of ET and S rats. It is concluded that although antioxidant enzyme activities are related to skeletal muscle oxidative capacity, the effects of exercise training on antioxidant enzymes in skeletal muscle cannot be predicted by measured changes in oxidative capacity.


1995 ◽  
Vol 269 (3) ◽  
pp. R557-R564 ◽  
Author(s):  
C. C. Barney ◽  
M. M. Folkerts

Male Sprague-Dawley rats were used to study the possible role of hyperthermia in the thirst associated with thermal dehydration. Rats were exposed to 40 degrees C for 4 h and then allowed access to water at different times after they were transferred to 25 degrees C. Delaying the time prior to allowing the rats to drink did not significantly alter either water intake or percent rehydration even though core temperature decreased during the first 1.5 h after removal from the heat. Exposing thermally dehydrated rats to 5 degrees C for 30 min prior to allowing them access to water also failed to significantly affect water intake or percent rehydration. Thermally dehydrated rats allowed to drink while remaining in the heat did not show a significant increase in water intake during the first hour or percent rehydration over rats drinking at 25 degrees C. Nondehydrated rats did show significant increases in water intake and percent rehydration when allowed to drink in the heat. Hyperthermia does not play a role in drinking in thermally dehydrated rats but can stimulate drinking in water-replete rats.


1995 ◽  
Vol 20 (2) ◽  
pp. 155-167 ◽  
Author(s):  
Marius Locke ◽  
Earl G. Noble

A class of proteins that undergoes preferential synthesis following a variety of stressors has been demonstrated to carry out important cellular functions under both stressed and nonstressed conditions. These so-called heat shock (HSP) or stress (SP) proteins have been termed "molecular chaperones" and play important roles in cellular transportation, assembly/degradation, and cell survival. This review provides a basic introduction to the function and regulation of these proteins. Emphasis is placed on members of the HSP 70 family of proteins (especially HSP 72) and their role in cellular protection, their pattern of distribution in skeletal muscle, and changes in their expression following exercise and exercise training. Key words: exercise, heat shock, HSP 72, skeletal muscle


2001 ◽  
Vol 2 (4) ◽  
pp. 267-276 ◽  
Author(s):  
Pamela J. Rowsey ◽  
Bonnie L. Metzger ◽  
Christopher J. Gordon

Chronic exercise conditioning has been shown to alter basal thermoregulatory processes (change in thermoregulatory set point) as well as the response to infectious fever. Chlorpyrifos (CHP), an organophosphate insecticide, also affects thermoregulation, causing an acute period of hypothermia followed by a delayed fever. This study examined whether chronic exercise training in the rat alters the thermoregulatory response to CHP. Core temperature and motor activity were monitored by radiotelemetry in female Sprague-Dawley rats housed individually at an ambient temperature of 22 °C. The rats were either given continuous access to running wheels or housed in standard cages without wheels. The exercise group ran predominately at night. After 8 weeks, the rats were gavaged with corn oil or 15 mg/kg CHP. CHP induced a transient hypothermic response followed by a delayed fever, beginning 1 day after exposure. Relative to controls, Tc decreases were not significantly different between the exercise (1.6 °C) group and the sedentary (0.5 °C) group given CHP. The sedentary and exercise group administered CHP developed a fever the day after CHP treatment. The fever response was greater in the sedentary group and persisted for approximately 3 days postinjection. Fever of the exercise group persisted for just one-half of 1 day after CHP. It is well known that chronic exercise training improves aerobic capacity; however, trained rats were not protected from the hypothermic effects of CHP. Training did ameliorate the febrile effects of CHP. Thus, exercise training may afford protection to the toxic effects of organophosphate insecticides.


2006 ◽  
Vol 76 (5) ◽  
pp. 324-331 ◽  
Author(s):  
Marsh ◽  
Laursen ◽  
Coombes

Erythrocytes transport oxygen to tissues and exercise-induced oxidative stress increases erythrocyte damage and turnover. Increased use of antioxidant supplements may alter protective erythrocyte antioxidant mechanisms during training. Aim of study: To examine the effects of antioxidant supplementation (α-lipoic acid and α-tocopherol) and/or endurance training on the antioxidant defenses of erythrocytes. Methods: Young male Wistar rats were assigned to (1) sedentary; (2) sedentary and antioxidant-supplemented; (3) endurance-trained; or (4) endurance-trained and antioxidant-supplemented groups for 14 weeks. Erythrocyte superoxide dismutase (SOD), glutathione peroxidase (GPX), and catalase (CAT) activities, and plasma malondialdehyde (MDA) were then measured. Results: Antioxidant supplementation had no significant effect (p > 0.05) on activities of antioxidant enzymes in sedentary animals. Similarly, endurance training alone also had no effect (p > 0.05). GPX (125.9 ± 2.8 vs. 121.5 ± 3.0 U.gHb–1, p < 0.05) and CAT (6.1 ± 0.2 vs. 5.6 ± 0.2 U.mgHb–1, p < 0.05) activities were increased in supplemented trained animals compared to non-supplemented sedentary animals whereas SOD (61.8 ± 4.3 vs. 52.0 ± 5.2 U.mgHb–1, p < 0.05) activity was decreased. Plasma MDA was not different among groups (p > 0.05). Conclusions: In a rat model, the combination of exercise training and antioxidant supplementation increased antioxidant enzyme activities (GPX, CAT) compared with each individual intervention.


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