|
|
|
Skeletal muscle alterations and exercise performance decrease in erythropoietin-deficient mice: a comparative study
|
| submitted by morc 11 months ago
|
|
Erythropoietin (EPO) is known to improve exercise performance by increasing oxygen blood transport and thus inducing a higher maximum oxygen uptake (VO2max). Furthermore, treatment with (or overexpression of) EPO induces protective effects in several tissues, including the myocardium. However, it is not known whether EPO exerts this protective effect when present at physiological levels. Given that EPO receptors have been identified in skeletal muscle, we hypothesized that EPO may have a direct, protective effect on this tissue. Thus, the objectives of the present study were to confirm a decrease in exercise performance and highlight muscle transcriptome alterations in a murine EPO functional knock-out model (the EPO-d mouse). We determined VO2max peak velocity and critical speed in exhaustive runs in 17 mice (9 EPO-d animals and 8 inbred controls), using treadmill enclosed in a metabolic chamber. Mice were sacrificed 24h after a last exhaustive treadmill exercise at critical speed. The tibialis anterior and soleus muscles were removed and total RNA was extracted for microarray gene expression analysis. The EPO-d mice's hematocrit was about 5% lower than that of controls (p<.5) and their performance level was about 25% lower (p<.1). A total of 1583 genes exhibited significant changes in their expression levels. However, 68 genes were strongly up-regulated (normalized ratio>1.4) and 115 were strongly down-regulated (normalized ratio<.8). The transcriptome data mining analysis showed that the exercise in the EPO-d mice induced muscle hypoxia, oxidative stress and proteolysis associated with energy pathway disruptions in glycolysis and mitochondrial oxidative phosphorylation. Our results showed that the lack of functional EPO induced a decrease in the aerobic exercise capacity. This decrease was correlated with the hematocrit and reflecting poor oxygen supply to the muscles. The observed alterations in the muscle transcriptome suggest that physiological concentrations of EPO exert both direct and indirect muscle-protecting effects during exercise. However, the signaling pathway involved in these protective effects remains to be described in detail.
|
| Topic: Biology |
|
Add your comment
Please Login or Signup to leave a comment
Related stories
|
|
| Interleukin-6 mediates exercise-induced increase in insulin sensitivity in mice |
| submitted by ilinolep 1 year and 1 month ago - Topic: Biology |
|
Interleukin-6 (IL-6) is released from working skeletal muscle during exercise. We investigated the acute and the long-term beneficial effects of IL-6 on exercise-induced glucose uptake in skeletal muscle and insulin sensitivity. The acute effect on exercise-induced glucose uptake was measured in ...
|
|
|
|
| Gene expression of carnosine-related enzymes and transporters in skeletal muscle |
| submitted by ramada12 7 months ago - Topic: Health |
|
Chronic oral beta-alanine supplementation can elevate muscle carnosine (beta-alanyl-l-histidine) content and improve high-intensity exercise performance. However, the regulation of muscle carnosine levels is poorly understood. The uptake of the rate-limiting precursor beta-alanine and the enzyme ...
|
|
|
|
| Effects of recombinant human erythropoietin in normal humans |
| submitted by hononnsaar 2 years and 3 months ago - Topic: Biology |
|
This review describes some of the physiological effects of recombinant human erythropoietin (EPO) in healthy humans. At the blood level EPO increases the arterial O2 content not only by increasing red blood cell volume, but also by an equally important decrease in plasma volume. Well before that,...
|
|
|
|
