Muscle Of Exercise-trained Rats Research Articles

Voluntary wheel exercise training affects locomotor muscle, but not the diaphragm in the rat.

Introduction: Functional tests and training regimens intensity-controlled by an individual are used in sport practice, clinical rehabilitation, and space medicine. The model of voluntary wheel running in rats can be used to explore molecular mechanisms of such training regimens in humans. Respiratory and locomotor muscles demonstrate diverse adaptations to treadmill exercise, but the effects of voluntary exercise training on these muscle types have not been compared yet. Therefore, this work aimed at the effects of voluntary ET on rat triceps brachii and diaphragm muscles with special attention to reactive oxygen species, which regulate muscle plasticity during exercise. Methods: Male Wistar rats were distributed into exercise trained (ET) and sedentary (Sed) groups. ET group had free access to running wheels, running activity was continuously recorded and analyzed using the original hardware/software complex. After 8weeks, muscle protein contents were studied using Western blotting. Results: ET rats had increased heart ventricular weights but decreased visceral/epididymal fat weights and blood triglyceride level compared to Sed. The training did not change corticosterone, testosterone, and thyroid hormone levels, but decreased TBARS content in the blood. ET rats demonstrated higher contents of OXPHOS complexes in the triceps brachii muscle, but not in the diaphragm. The content of SOD2 increased, and the contents of NOX2 and SOD3 decreased in the triceps brachii muscle of ET rats, while there were no such changes in the diaphragm. Conclusion: Voluntary wheel running in rats is intensive enough to govern specific adaptations of muscle fibers in locomotor, but not respiratory muscle.

Biotin and chromium histidinate improve glucose metabolism and proteins expression levels of IRS-1, PPAR-\u03b3, and NF-\u03baB in exercise-trained rats

BackgroundChromium histidinate (CrHis) and biotin are micronutrients commonly used to improve health by athletes and control glycaemia by patients with diabetes. This study investigates the effects of 8-week regular exercise training in rats together with dietary CrHis and biotin supplementation on glucose, lipids and transaminases levels, as well as protein expression levels of peroxisome proliferator-activated receptor gamma (PPAR-γ), insulin receptor substrate-1 (IRS-1) and nuclear transcription factor kappa B (NF-κB).MethodsA total of 56 male Wistar rats were randomly divided into 8 groups of 7 animals each and treated as follows: Control, CrHis, Biotin, CrHis+Biotin, Exercise, CrHis+Exercise, Biotin+Exercise, and CrHis+Biotin+Exercise. The doses of CrHis and biotin were 400 μg/kg and 6 mg/kg of diet, respectively. The training program consisted of running at 30 m/min for 30 min/day at 0% grade level, 5 days per week, once a day for 6 weeks. Serum glucose, total cholesterol (TC), high-density lipoprotein cholesterol (HDL), triglycerides (TG), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were measured with an automatic biochemical analyzer. Muscle and liver PPAR-γ, IRS-1 and NF-κB expressions were detected with real-time polymerase chain reaction.ResultsRegular exercise significantly (p < 0.001) decreased glucose, TC and TG levels, but increased HDL cholesterol. Dietary CrHis and biotin supplementation exhibited a significant (p < 0.001) decrease in glucose (effect size = large; ƞ2 = 0.773) and TG (effect size = large; ƞ2 = 0.802) levels, and increase in HDL cholesterol compared with the exercise group. No significant change in AST and ALT (effect size = none) levels was recorded in all groups (p > 0.05). CrHis/biotin improves the proteins expression levels of IRS-1, PPAR-γ, and NF-κB (effect size: large for all) in the liver and muscle of sedentary and regular exercise-trained rats (p < 0.001).ConclusionsCrHis/biotin supplementation improved serum glucose and lipid levels as well as proteins expression levels of PPAR-γ, IRS-1 and NF-κB in the liver and muscle of exercise-trained rats, with the highest efficiency when administered together. CrHis/biotin may represent an effective nutritional therapy to improve health.

Exercise training stimulates heat shock protein expression in the rat placenta

While exercise during pregnancy is generally recommended and thought to be beneficial to mother and fetus, the metabolic adaptations to exercise during pregnancy remain poorly understood. Heat shock proteins (HSPs) are important cytoprotective molecules and could play an important role in adaptations to exercise during pregnancy. Thus, we hypothesized that exercise training during pregnancy results in increased skeletal muscle and placental HSP expression. Female rats were given access to an exercise wheel for 6 weeks prior to and during pregnancy. On day 19 of pregnancy tissues were collected and snap frozen for later analysis. Western blots were performed in skeletal muscle and placenta. HSPs 27 (3.7 ± 0.36 vs. 2.2 ± 0.38; P < 0.05), 60 (2.2 ± 0.73 vs. 0.49 ± 0.08; P<0.05) and 90 (0.33 ± 0.09 vs. 0.11 ± 0.02; P < 0.05) were increased in the placentas of exercise trained rats when compared to sedentary controls. In contrast, HSPs 27, 60 and 90 were unchanged in hind limb skeletal muscle of exercise trained rats when contrasted with sedentary controls. The present data indicates chronic exercise training stimulates HSP expression in the placenta but not in skeletal muscle during late gestation. Increased expression of HSPs as a result of exercise could provide a preconditioning effect that may be protective against cellular damage during pregnancies complicated with conditions such as hypertension and preeclampsia.

Octacosanol Supplementation Increases Running Endurance Time and Improves Biochemical Parameters After Exhaustion in Trained Rats

This study evaluated the effects of octacosanol on running performance and related biochemical parameters in exercise-trained rats run to exhaustion on a treadmill. Male Sprague-Dawley rats were randomly assigned to one of three groups - sedentary control group (SC), exercise-trained control group (EC), and exercise-trained, octacosanol-supplemented group (EO) - and raised on either control or octacosanol (0.75%)-supplemented diet with (or without for SC rats) exercise-training for 4 weeks. EC rats ran 184% longer until exhaustion than SC rats (P <.01), while octacosanol-supplemented trained rats ran 46% longer than EC rats (P <.05). Under the exhausted state immediately following the running performance test, EO rats exhibited significantly higher plasma ammonia and lactate concentrations compared with the values for EC rats (P <.05). Although EO rats ran significantly longer until exhausted, their plasma glucose level and gastronecmius muscle glycogen concentration were not significantly different from those of EC rats. Dietary supplementation of octacosanol resulted in significantly higher creatine phosphokinase activity in plasma (44% increase, P <.01) and citrate synthase activity in muscle (16% increase, P<.01) of exercise-trained rats. These results suggest that the ergogenic properties of octacosanol include the sparing of muscle glycogen stores and increases in the oxidative capacity in the muscle of exercise-trained rats.