Proteomic analysis of rat skeletal muscle submitted to one bout of incremental exercise.

Exercise can alter gene transcriptional and protein translational rates leading to changes in protein abundance toward adaptation to exercise. We investigated the alterations in protein abundance in skeletal muscle after one bout of an exhaustive exercise through proteomic analysis. Gastrocnemius muscles were sampled from non-exercised control rats and from rats exercised on a treadmill with incremental increases in speed until exhaustion (approximately 30 min). Rats were sacrificed 3 and 24 h after exercise cessation. Two-dimensional gel electrophoresis was performed and spots with a significant alteration in relative volume were identified by mass spectrometry. Six spots presented statistically significant altered abundances after exercise. The spots identified as the metabolic related proteins triosephosphate isomerase 1, glyceraldehyde-3-phosphate dehydrogenase, the ß subunit of pyruvate dehydrogenase E(1) and carnitine palmitoyltransferase 2 were all more abundant after exercise. One spot identified as heat shock cognate 70 was also more abundant after exercise. One spot demonstrated a decreased abundance after exercise and was identified as α-actin. These results suggest that a single session of exhaustive incremental exercise in untrained muscle can alter thin filaments synthesis/degradation rate and enhance cytosolic and mitochondrial proteins synthesis. The identified proteins may be important to a general preconditioning of skeletal muscle for subsequent exercise sessions.

High-intensity ultraendurance promotes early release of muscle injury markers.

OBJECTIVE: To evaluate the impact of high-intensity ultraendurance (HIU) cycling, using it as a possible way to understand muscle injury kinetics and blood immune cells' release during high-intensity prolonged exercise DESIGN: Male amateur triathletes enrolled during a cycling race of the International Bike Championship 800 km cycling relay (approximately 23 h). Each athlete alternately cycled 20-25 minutes until exhaustion and performed a total of approximately 200 km. RESULTS: Creatine kinase levels in blood reached a 300% rise in a sigmoidal pattern, while lactate dehydrogenase levels increased by 30-40% following a hyperbolic pattern. Aspartate aminotransferase and alanine aminotransferase levels increased by up to 250% and 140%, respectively. Liver injury markers such as alkaline phosphatase and gamma-glutamyltransferase remained stable. Platelets increased by 20-30% from pre-exercise, and there was no change in haematocrit during the race. White blood cells rose by nearly 200%. Leucocytes rose 210% during the race, with a major component coming from neutrophils, which increased more than 300%. Triacylglycerol levels were decreased at the finish and total cholesterol levels remained unchanged. Urate increased (by up to 35%) during the first half of the race, and urea levels increased with a different pattern, increasing by 45% in the second half. CONCLUSIONS: This study showed the blood appearance kinetics of muscle injury markers and some metabolites. It is suggested that the increase in these enzymes came primarily from muscle damage, rather than liver damage, and that white blood cells are selectively mobilised independently of haemoconcentration. The early appearance of muscle injury markers in this kind of exercise was also shown.

Voluntary wheel running: patterns and physiological effects in mice.

Exercise can prevent and improve the pathophysiology of diseases and promote healthy aging. Thus, understanding the mechanisms that regulate the beneficial effects of exercise may lead to the development of new strategies to enhance quality of life and to counteract chronic diseases. Voluntary wheel running is an interesting model to study the effects of exercise in mice. Compared to forced treadmill exercise, voluntary wheel running presents several advantages such as: 1) running pattern is similar to natural running behavior of mice; 2) it is performed under non-stressed conditions, according to the rhythmicity of the animal; 3) it does not require direct interference from the researcher, and can be easily applied in long-term studies. Mice run spontaneously when given access to running wheels, for a total distance of ∼4 to 20 km per day and a total activity time of ∼3 to 7 hours a day. Hence, voluntary wheel running can result in robust endurance-like adaptation in skeletal and cardiac muscles and protect from sarcopenia. However, due to the lack of control over exercise parameters in voluntary exercise models, it is important for the researcher to understand the patterns and variability of wheel running in mice, as well as the factors that can affect voluntary running activity. Overall, voluntary wheel running in mice is a very interesting approach to study the chronic adaptation to exercise, analyze the effects of exercise, and test exercise capacity in different experimental models.

Voluntary wheel running: patterns and physiological effects in mice

Exercise can prevent and improve the pathophysiology of diseases and promote healthy aging. Thus, understanding the mechanisms that regulate the beneficial effects of exercise may lead to the development of new strategies to enhance quality of life and to counteract chronic diseases. Voluntary wheel running is an interesting model to study the effects of exercise in mice. Compared to forced treadmill exercise, voluntary wheel running presents several advantages such as: 1) running pattern is similar to natural running behavior of mice; 2) it is performed under non-stressed conditions, according to the rhythmicity of the animal; 3) it does not require direct interference from the researcher, and can be easily applied in long-term studies. Mice run spontaneously when given access to running wheels, for a total distance of ∼4 to 20 km per day and a total activity time of ∼3 to 7 hours a day. Hence, voluntary wheel running can result in robust endurance-like adaptation in skeletal and cardiac muscles and protect from sarcopenia. However, due to the lack of control over exercise parameters in voluntary exercise models, it is important for the researcher to understand the patterns and variability of wheel running in mice, as well as the factors that can affect voluntary running activity. Overall, voluntary wheel running in mice is a very interesting approach to study the chronic adaptation to exercise, analyze the effects of exercise, and test exercise capacity in different experimental models.